Judith river formation

@inproceedings{leidy1856notices2,
    author = "Leidy, J",
    title = "Notices of remains of extinct reptiles and fishes, discovered by Dr. F.V. Hayden in the badlands of the Judith River, Nebraska Territory",
    year = "1856",
    booktitle = "Proceedings of the National Academy of Science, Philadelphia, v. 8, p. 72- 73",
    note = "talkorigins\_source = {true}; raw\_reference = {Leidy, J., 1856, Notices of remains of extinct reptiles and fishes, discovered by Dr. F.V. Hayden in the badlands of the Judith River, Nebraska Territory: Proceedings of the National Academy of Science, Philadelphia, v. 8, p. 72- 73.}"
}

BSERVANT collectors and students of iO) vertebrate paleontology, who have stuen died the Belly River and Edmonton met faunas fully realize that, in spite of the many fine dinosaurian specimens which have been collected from these beds in recent years, many forms are still imperfectly known.Perhaps the light-limbed theropods are among the least known of these dinosaurs.Three genera of light-limbed theropods have been described from the Belly River formation of Alberta but only one, Struthiomimus, is represented by a considerable part of the skeleton.The scarcity of fossilized remains of these forms may be due partly to the frailness of the bones and in part to a possible upland habitat.As these beds are essentially delta and flood-plain deposits complete skeletons of the animals, which lived back from the streams or far away from the deltas, would seldom be buried intact.In view of the scarcity of such remains it was with great 'satisfaction that, during the field season of 1928, the writer discovered, in the Belly River forma-' tion of Alberta, two distinct, undescribed, forms of light-limbed theropods.CLASSIFICATION AND DISCUSSION Vertebrate paleontologists do not fully agree on the classification of the Theropoda.Gilmore! and Nopcsa?refer the deinodonts to the Megalosauride whereas Matthew and Brown? and Huene! regard them as more nearly related to the Ornithomimid#.Gilmore and Matthew and Brown refer Ornithomimus and Celurus to distinct families, the Ornithomimide and Cceluride while Nopcsa refers both to the family Compsognathidz.For the purpose of this paper the deino-_donts, ornithomimids and ccelurids are regarded as representing distinct families all of which are somewhat closely related.

@article{doi105962p339375,
    author = "Sternberg, C M",
    title = "Two New Theropod Dinosaurs from the Belly River Formation of Alberta",
    year = "1932",
    journal = "The Canadian Field-Naturalist",
    abstract = "BSERVANT collectors and students of iO) vertebrate paleontology, who have stuen died the Belly River and Edmonton met faunas fully realize that, in spite of the many fine dinosaurian specimens which have been collected from these beds in recent years, many forms are still imperfectly known.Perhaps the light-limbed theropods are among the least known of these dinosaurs.Three genera of light-limbed theropods have been described from the Belly River formation of Alberta but only one, Struthiomimus, is represented by a considerable part of the skeleton.The scarcity of fossilized remains of these forms may be due partly to the frailness of the bones and in part to a possible upland habitat.As these beds are essentially delta and flood-plain deposits complete skeletons of the animals, which lived back from the streams or far away from the deltas, would seldom be buried intact.In view of the scarcity of such remains it was with great 'satisfaction that, during the field season of 1928, the writer discovered, in the Belly River forma-' tion of Alberta, two distinct, undescribed, forms of light-limbed theropods.CLASSIFICATION AND DISCUSSION Vertebrate paleontologists do not fully agree on the classification of the Theropoda.Gilmore! and Nopcsa?refer the deinodonts to the Megalosauride whereas Matthew and Brown? and Huene! regard them as more nearly related to the Ornithomimid\#.Gilmore and Matthew and Brown refer Ornithomimus and Celurus to distinct families, the Ornithomimide and Cceluride while Nopcsa refers both to the family Compsognathidz.For the purpose of this paper the deino-\_donts, ornithomimids and ccelurids are regarded as representing distinct families all of which are somewhat closely related.",
    url = "https://doi.org/10.5962/p.339375",
    doi = "10.5962/p.339375",
    openalex = "W2732271194"
}

A fragmentary skeleton of Stenonychosaurus inequalis indicates that this small theropod dinosaur is very closely related to Saurornithoides mongoliensis from the Cretaceous of central Asia. Both forms possessed relatively well developed cerebral hemispheres and large eyes, and were probably fleet bipeds with supple raptorial forelimbs. Their extreme rarity as fossils is attributed to their preference for environments not usually preserved in the stratigraphic record.

@article{russell1969a,
    author = "Russell, Dale A.",
    title = "A new specimen of Stenonychosaurus from the Oldman Formation (Cretaceous) of Alberta",
    year = "1969",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "A fragmentary skeleton of Stenonychosaurus inequalis indicates that this small theropod dinosaur is very closely related to Saurornithoides mongoliensis from the Cretaceous of central Asia. Both forms possessed relatively well developed cerebral hemispheres and large eyes, and were probably fleet bipeds with supple raptorial forelimbs. Their extreme rarity as fossils is attributed to their preference for environments not usually preserved in the stratigraphic record.",
    url = "https://doi.org/10.1139/e69-059",
    doi = "10.1139/e69-059",
    number = "4",
    pages = "595-612",
    volume = "6"
}

@article{doi1010160031018271900447,
    author = "Dodson, Peter",
    title = "Sedimentology and taphonomy of the Oldman Formation (Campanian), Dinosaur Provincial Park, Alberta (Canada)",
    year = "1971",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/0031-0182(71)90044-7",
    doi = "10.1016/0031-0182(71)90044-7",
    openalex = "W1973699641",
    references = "doi1010079783662010204, doi101086626329, doi101111j136530911963tb01204x, doi101111j136530911964tb00459x, doi101111j136530911965tb01561x, doi101111j155856461968tb03995x, doi10113000167606195364381tfsaci20co2, doi101130spe40p1, doi102113gsrocky8specialpaper11, doi1023071934999, doi102475ajs2628975, doi105962bhltitle52089, doi105962p339375, openalexw2591879035, openalexw337536883, openalexw607142922"
}

The family Ornithomimidae is defined on the basis of the skeletal morphology of the three genera Ornithomimus, Struthiomimus, and Dromiceiomimus known in continental strata in Alberta, which are temporally equivalent to the Upper Campanian substage. At least two genera occur in Canadian Lance (Upper Maestrichtian) equivalent strata, but cannot be identified at present. A group of more primitive ornithomimoid theropods is represented else-where by the late Jurassic Elaphrosaurus and early Cretaceous Archaeornithomimus.Ornithomimid attributes include a general body form which parallels that of the ratites; elongate forelimbs, a kinetic skull, enormous eyes, a relatively highly evolved brain, and possibly a secondary palate and supertemporal fenestrae which were nearly encircled by alae of the squamosal. A reconstruction of the myology of the thigh indicates that ornithomimids were extremely fleet, but lacked the agility characteristic of modern large ground birds. They probably subsisted on small, soft-bodied animals.

@article{doi101139e72031,
    author = "Russell, Dale A.",
    title = "Ostrich Dinosaurs from the Late Cretaceous of Western Canada",
    year = "1972",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The family Ornithomimidae is defined on the basis of the skeletal morphology of the three genera Ornithomimus, Struthiomimus, and Dromiceiomimus known in continental strata in Alberta, which are temporally equivalent to the Upper Campanian substage. At least two genera occur in Canadian Lance (Upper Maestrichtian) equivalent strata, but cannot be identified at present. A group of more primitive ornithomimoid theropods is represented else-where by the late Jurassic Elaphrosaurus and early Cretaceous Archaeornithomimus.Ornithomimid attributes include a general body form which parallels that of the ratites; elongate forelimbs, a kinetic skull, enormous eyes, a relatively highly evolved brain, and possibly a secondary palate and supertemporal fenestrae which were nearly encircled by alae of the squamosal. A reconstruction of the myology of the thigh indicates that ornithomimids were extremely fleet, but lacked the agility characteristic of modern large ground birds. They probably subsisted on small, soft-bodied animals.",
    url = "https://doi.org/10.1139/e72-031",
    doi = "10.1139/e72-031",
    openalex = "W2140641637",
    references = "doi101002jmor1051140102, doi1010160031018271900447, doi105962bhltitle14474, openalexw1879660213, openalexw3208547338"
}

Sahni, Ashok (1972): The vertebrate Fauna of the Judith River formation, Montana. Bulletin of the American Museum of Natural History 147 (6): 319-416, DOI: 10.5281/zenodo.3382461, Hdl: http://hdl.handle.net/2246/1099

@article{doi105281zenodo3382461,
    author = "Sahni, Ashok",
    title = "The vertebrate Fauna of the Judith River formation, Montana",
    year = "1972",
    journal = "Zenodo (CERN European Organization for Nuclear Research)",
    abstract = "Sahni, Ashok (1972): The vertebrate Fauna of the Judith River formation, Montana. Bulletin of the American Museum of Natural History 147 (6): 319-416, DOI: 10.5281/zenodo.3382461, Hdl: http://hdl.handle.net/2246/1099",
    url = "https://doi.org/10.5281/zenodo.3382461",
    doi = "10.5281/zenodo.3382461",
    openalex = "W3210764569"
}

Marshosaurus bicentesimus (Reptilia: Saurischia), a new theropod dinosaur from the Late Jurassic Morrison Formation of east central Utah, is distinct from other Morrison theropods, Allosaurus, Ceratosaurus, and Stokesosaurus, of the Cleveland-Lloyd Dinosaur Collection in the unusual character of the type specimen, a left ilium, and in the referred materials, which include the toothbearing elements of the skull and jaw and the complete pelvic girdle. A relatively complete, articulated skeleton of Marshosaurus is unknown at this time.

@article{doi1034191ug3151,
    author = "Madsen, James H.",
    title = "A Second New Theropod Dinosaur from the Late Jurassic of East Central Utah",
    year = "1976",
    journal = "Utah Geology",
    abstract = "Marshosaurus bicentesimus (Reptilia: Saurischia), a new theropod dinosaur from the Late Jurassic Morrison Formation of east central Utah, is distinct from other Morrison theropods, Allosaurus, Ceratosaurus, and Stokesosaurus, of the Cleveland-Lloyd Dinosaur Collection in the unusual character of the type specimen, a left ilium, and in the referred materials, which include the toothbearing elements of the skull and jaw and the complete pelvic girdle. A relatively complete, articulated skeleton of Marshosaurus is unknown at this time.",
    url = "https://doi.org/10.34191/ug-3-1\_51",
    doi = "10.34191/ug-3-1\_51",
    openalex = "W1848094814"
}

Three dentaries of small theropod dinosaurs from the Judith River Formation of Alberta are described and their taxonomy is discussed. Two are referable to the Dromaeosauridae (Dromaeosaurus sp.) and the other to the Saurornithoididae. The structural differences seem to support recognition of two distinct families, Dromaeosauridae and Saurornithoididae, as proposed by some authors on the basis of other structural differences.

@article{doi101139e77061,
    author = "Sues, H.",
    title = "Dentaries of small theropods from the Judith River Formation (Campanian) of Alberta, Canada",
    year = "1977",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Three dentaries of small theropod dinosaurs from the Judith River Formation of Alberta are described and their taxonomy is discussed. Two are referable to the Dromaeosauridae (Dromaeosaurus sp.) and the other to the Saurornithoididae. The structural differences seem to support recognition of two distinct families, Dromaeosauridae and Saurornithoididae, as proposed by some authors on the basis of other structural differences.",
    url = "https://www.semanticscholar.org/paper/5ac5cb2b995bc40b98dae379937569601ab5d7ff",
    doi = "10.1139/E77-061",
    is_oa = "true",
    number = "4",
    pages = "587-592",
    semanticscholar_citation_count = "12",
    semanticscholar_id = "5ac5cb2b995bc40b98dae379937569601ab5d7ff",
    volume = "14"
}

Three dentaries of small theropod dinosaurs from the Judith River Formation of Alberta are described and their taxonomy is discussed. Two are referable to the Dromaeosauridae (Dromaeosaurus sp.) and the other to the Saurornithoididae. The structural differences seem to support recognition of two distinct families, Dromaeosauridae and Saurornithoididae, as proposed by some authors on the basis of other structural differences.

@article{sues1977dentaries,
    author = "Sues, Hans-Dieter",
    title = "Dentaries of small theropods from the Judith River Formation (Campanian) of Alberta, Canada",
    year = "1977",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Three dentaries of small theropod dinosaurs from the Judith River Formation of Alberta are described and their taxonomy is discussed. Two are referable to the Dromaeosauridae (Dromaeosaurus sp.) and the other to the Saurornithoididae. The structural differences seem to support recognition of two distinct families, Dromaeosauridae and Saurornithoididae, as proposed by some authors on the basis of other structural differences.",
    url = "https://doi.org/10.1139/e77-061",
    doi = "10.1139/e77-061",
    number = "4",
    openalex = "W2064327523",
    pages = "587-592",
    volume = "14",
    references = "doi101007bf02986567, doi104095105060, doi105281zenodo1048846, doi105281zenodo18028696, openalexw1879660213, russell1969a, sues1978a"
}

@article{sues1977dentaries4,
    author = "Sues, H.-D",
    title = "Dentaries of small theropods from the Judith River Formation (Campanian) of Alberta, Canada",
    year = "1977",
    journal = "Canadian Journal of Earth Sciences, v. 14, p. 587-592",
    note = "talkorigins\_source = {true}; raw\_reference = {Sues, H.-D., 1977, Dentaries of small theropods from the Judith River Formation (Campanian) of Alberta, Canada: Canadian Journal of Earth Sciences, v. 14, p. 587-592.}"
}

@article{doi101111j109636421978tb01049x,
    author = "Sues, H.",
    title = "A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta Canada.",
    year = "1978",
    journal = "Zoological Journal of the Linnean Society",
    url = "http://doc.rero.ch/record/13897/files/PAL\_E835.pdf",
    doi = "10.1111/J.1096-3642.1978.TB01049.X",
    is_oa = "true",
    number = "4",
    pages = "381-400",
    semanticscholar_citation_count = "105",
    semanticscholar_id = "6f94f06911fad9c23f49e847565be209018f8949",
    volume = "62"
}

ABSTRACT The South Saskatchewan River has a long term average discharge of 275 m 3 /sec, with flood peaks in the range of 1500 to 3800 m 3 /sec. South of Saskatoon, the four major types of geomorphological elements recognised are channels, slipface‐bounded bars, sand flats and vegetated islands and floodplains. Major channels are 3‐5 m deep, up to 200 m wide, and flow around sand flats which are 50‐2000 m long, and around vegetated islands up to 1 km long. At areas of flow expansion, long straight‐crested cross‐channel bars form. During falling stage, a small part of the crest of the cross‐channel bar may become emergent, and act as a nucleus for downstream and lateral growth of a new sand flat. The dominant channel bedforms are dunes, which deposit trough cross bedding. Cross‐channel bars deposit large sets of planar tabular cross bedding. Sand flats that grow from a nucleus on a cross‐channel bar are mostly composed of smaller planar tabular sets, with some parallel lamination, trough cross‐bedding, and ripple cross‐lamination. A typical facies sequence related to sand flat growth would consist of in‐channel trough cross‐bedding, overlain by a large (1‐2 m) planar tabular set (cross‐channel bar), overlain in turn by a complex association mostly of small planar tabular cross‐beds, trough cross‐beds and ripple cross‐lamination. By contrast, a second stratigraphic sequence can be proposed, related only to channel aggradation. It would consist dominantly of trough cross‐beds, decreasing in scale upward, and possible interrupted by isolated sets of planar tabular cross‐bedding if a cross‐channel bar formed, but failed to grow into a sand flat. During final filling of the channel, ripple cross‐lamination and thin clay layers may be deposited. In the S. Saskatchewan, these sequences are a minimum of 5 m thick, and are overlain by 0.5‐1 m of silty and muddy vertical accretion deposits.

@article{doi101111j136530911978tb00323x,
    author = "Cant, Douglas J. and Walker, Roger G.",
    title = "Fluvial processes and facies sequences in the sandy braided South Saskatchewan River, Canada",
    year = "1978",
    journal = "Sedimentology",
    abstract = "ABSTRACT The South Saskatchewan River has a long term average discharge of 275 m 3 /sec, with flood peaks in the range of 1500 to 3800 m 3 /sec. South of Saskatoon, the four major types of geomorphological elements recognised are channels, slipface‐bounded bars, sand flats and vegetated islands and floodplains. Major channels are 3‐5 m deep, up to 200 m wide, and flow around sand flats which are 50‐2000 m long, and around vegetated islands up to 1 km long. At areas of flow expansion, long straight‐crested cross‐channel bars form. During falling stage, a small part of the crest of the cross‐channel bar may become emergent, and act as a nucleus for downstream and lateral growth of a new sand flat. The dominant channel bedforms are dunes, which deposit trough cross bedding. Cross‐channel bars deposit large sets of planar tabular cross bedding. Sand flats that grow from a nucleus on a cross‐channel bar are mostly composed of smaller planar tabular sets, with some parallel lamination, trough cross‐bedding, and ripple cross‐lamination. A typical facies sequence related to sand flat growth would consist of in‐channel trough cross‐bedding, overlain by a large (1‐2 m) planar tabular set (cross‐channel bar), overlain in turn by a complex association mostly of small planar tabular cross‐beds, trough cross‐beds and ripple cross‐lamination. By contrast, a second stratigraphic sequence can be proposed, related only to channel aggradation. It would consist dominantly of trough cross‐beds, decreasing in scale upward, and possible interrupted by isolated sets of planar tabular cross‐bedding if a cross‐channel bar formed, but failed to grow into a sand flat. During final filling of the channel, ripple cross‐lamination and thin clay layers may be deposited. In the S. Saskatchewan, these sequences are a minimum of 5 m thick, and are overlain by 0.5‐1 m of silty and muddy vertical accretion deposits.",
    url = "https://doi.org/10.1111/j.1365-3091.1978.tb00323.x",
    doi = "10.1111/j.1365-3091.1978.tb00323.x",
    openalex = "W2058510863",
    references = "doi1010160012825277900551, doi101016001282527990059x, doi1010160022169465901010, doi1010160037073869900104, doi10108020014422195611880887, doi101086627959, doi101111j136530911965tb01561x, doi101139e77058, doi101306212f6ff52b2411d78648000102c1865d, doi102110scn7502"
}

@article{sues1978a,
    author = "SUES, HANS-DIETER",
    title = "A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta Canada",
    year = "1978",
    journal = "Zoological Journal of the Linnean Society",
    url = "https://doi.org/10.1111/j.1096-3642.1978.tb01049.x",
    doi = "10.1111/j.1096-3642.1978.tb01049.x",
    number = "4",
    openalex = "W1967143228",
    pages = "381-400",
    volume = "62",
    references = "doi102307jctvqc6gzx, doi104095105003, doi105281zenodo1040973, doi105962p339375, openalexw2597671315, russell1969a, sues1977dentaries"
}

@article{sues1978a5,
    author = "Sues, H.-D",
    title = "A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta Canada",
    year = "1978",
    journal = "Zoological Journal of the Linnean Society, v. 62, p. 381-400",
    note = "talkorigins\_source = {true}; raw\_reference = {Sues, H.-D., 1978, A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta Canada: Zoological Journal of the Linnean Society, v. 62, p. 381-400.}"
}

@article{wilson1985stenonychosaurus6,
    author = "Wilson, M. C. and Currie, P. J",
    title = "Stenonychosaurus inequalis (Saurischia",
    year = "1985",
    journal = "Theropoda) from the Judith River (Oldman) Formation of Alberta: new findings on metatarsal structure: Canadian Journal of Earth Sciences, v. 22, p. 1813-1817",
    note = "talkorigins\_source = {true}; raw\_reference = {Wilson, M. C., and Currie, P. J., 1985, Stenonychosaurus inequalis (Saurischia: Theropoda) from the Judith River (Oldman) Formation of Alberta: new findings on metatarsal structure: Canadian Journal of Earth Sciences, v. 22, p. 1813-1817.}"
}

@inproceedings{currie1987theropods1,
    author = "Currie, P. J",
    title = "Theropods of the Judith River Formation of Dinosaur Provincial Park, Alberta, Canada, in Currie, P. J., and Koster, E., eds., Fourth Symposium on Mesozoic Terrestrial Ecosystems",
    year = "1987",
    booktitle = "Drumheller, Canada, Tyrrell Museum, p. 52-59",
    note = "talkorigins\_source = {true}; raw\_reference = {Currie, P. J., 1987, Theropods of the Judith River Formation of Dinosaur Provincial Park, Alberta, Canada, in Currie, P. J., and Koster, E., eds., Fourth Symposium on Mesozoic Terrestrial Ecosystems: Drumheller, Canada, Tyrrell Museum, p. 52-59.}"
}

@misc{paul1988the3,
    author = "Paul, G. S",
    title = "THe horned theropods of the Morrison and Great Oolite, and the sickle-claw theropods of the Cloverly, Djadokhta and Judith River",
    year = "1988",
    howpublished = "Hunteria, v. 2, p. 1-9",
    note = "talkorigins\_source = {true}; raw\_reference = {Paul, G. S., 1988, THe horned theropods of the Morrison and Great Oolite, and the sickle-claw theropods of the Cloverly, Djadokhta and Judith River: Hunteria, v. 2, p. 1-9.}"
}

@article{brinkman1990paleooecology,
    author = "Brinkman, Donald B.",
    title = "Paleooecology of the Judith River Formation (Campanian) of Dinosaur Provincial Park, Alberta, Canada: Evidence from vertebrate microfossil localities",
    year = "1990",
    journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
    url = "https://doi.org/10.1016/0031-0182(90)90203-j",
    doi = "10.1016/0031-0182(90)90203-j",
    number = "1-2",
    openalex = "W2025865290",
    pages = "37-54",
    volume = "78",
    references = "doi1010160031018288900740, doi101016003101828890096x, doi101016030544038590072x, doi1010160305440386900488, doi101016s0037073887800064, doi101017cbo9780511608377011, doi1023071933240, doi1023072260325, doi102307281081, doi1023073514695, openalexw337536883"
}

@article{doi101016003101829090202i,
    author = "Eberth, D.",
    title = "Stratigraphy and sedimentology of vertebrate microfossil sites in the uppermost Judith River Formation (Campanian), Dinosaur Provincial Park, Alberta, Canada",
    year = "1990",
    journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
    url = "https://www.semanticscholar.org/paper/433783638bba857b382a6de8225f5ff015192dc6",
    doi = "10.1016/0031-0182(90)90202-I",
    is_oa = "true",
    number = "1-2",
    pages = "1-36",
    semanticscholar_citation_count = "89",
    semanticscholar_id = "433783638bba857b382a6de8225f5ff015192dc6",
    volume = "78"
}

@article{doi101016003101829090203j,
    author = "Brinkman, D.",
    title = "Paleooecology of the Judith River Formation (Campanian) of Dinosaur Provincial Park, Alberta, Canada: Evidence from vertebrate microfossil localities",
    year = "1990",
    journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
    url = "https://www.semanticscholar.org/paper/28db68b3f1401fdd2af9e3a428ce1fcd4a147eb8",
    doi = "10.1016/0031-0182(90)90203-J",
    is_oa = "true",
    number = "1-2",
    pages = "37-54",
    semanticscholar_citation_count = "143",
    semanticscholar_id = "28db68b3f1401fdd2af9e3a428ce1fcd4a147eb8",
    volume = "78"
}

@article{doi101017cbo9780511608377011,
    author = "Currie, P. and Rigby, J. and Sloan, R. E.",
    title = "Dinosaur Systematics: Theropod teeth from the Judith River Formation of southern Alberta, Canada",
    year = "1990",
    booktitle = "Dinosaur Systematics",
    url = "https://www.semanticscholar.org/paper/fedead3cc1ae0ec35f3954946391d9906ed25ae7",
    doi = "10.1017/CBO9780511608377.011",
    is_oa = "true",
    pages = "107-126",
    semanticscholar_citation_count = "246",
    semanticscholar_id = "fedead3cc1ae0ec35f3954946391d9906ed25ae7"
}

@article{eberth1990stratigraphy,
    author = "Eberth, D.A.",
    title = "Stratigraphy and sedimentology of vertebrate microfossil sites in the uppermost Judith River Formation (Campanian), Dinosaur Provincial Park, Alberta, Canada",
    year = "1990",
    journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
    url = "https://doi.org/10.1016/0031-0182(90)90202-i",
    doi = "10.1016/0031-0182(90)90202-i",
    number = "1-2",
    openalex = "W2016498987",
    pages = "1-36",
    volume = "78",
    references = "brinkman1990paleooecology, doi1010079783642814983, doi1010160012821x77900607, doi101016001282527990059x, doi1010160012825283900223, doi1010160012825285900017, doi1010160012825287900419, doi1010160037073869900104, doi101016s0037073887800064, doi101038142234b0, doi1023073514678, openalexw602333724"
}

Four new genera and five new species of Teiidae (Lacertilia), based on newly discovered specimens from the Upper Cretaceous Oldman Formation (Judithian), Alberta, Canada, are named and described. A brief review of the Cretaceous record of the Teiidae in both North America and central Asia is presented. Recognition of the new teiids and work in progress shows that, contrary to previous authors, the North American Judithian lizard fauna is significantly different taxonomically from that of Lancian age and, hence, represents a previously unrecognized episode in the evolutionary history of teiids. The stratigraphic distribution of teiid fossils in the Cretaceous of North America suggests that the unicuspid tooth form is primitive for the family Teiidae.

@article{doi105962p330465,
    author = "Gao, Ke‐Qin and Fox, Richard C.",
    title = "New teiid lizards from the Upper Cretaceous Oldman Formation (Judithian) of southeastern Alberta, Canada, with a review of the Cretaceous record of teiids",
    year = "1991",
    journal = "Annals of Carnegie Museum",
    abstract = "Four new genera and five new species of Teiidae (Lacertilia), based on newly discovered specimens from the Upper Cretaceous Oldman Formation (Judithian), Alberta, Canada, are named and described. A brief review of the Cretaceous record of the Teiidae in both North America and central Asia is presented. Recognition of the new teiids and work in progress shows that, contrary to previous authors, the North American Judithian lizard fauna is significantly different taxonomically from that of Lancian age and, hence, represents a previously unrecognized episode in the evolutionary history of teiids. The stratigraphic distribution of teiid fossils in the Cretaceous of North America suggests that the unicuspid tooth form is primitive for the family Teiidae.",
    url = "https://doi.org/10.5962/p.330465",
    doi = "10.5962/p.330465",
    openalex = "W4290997236",
    references = "doi104095105060, fassett1977geology"
}

ABSTRACT The Terlingua local fauna is a rich assemblage of predominantly terrestrial micro vertebrates from the Upper Cretaceous Aguja Formation of Trans-Pecos Texas. Marine invertebrates (which include elements of both Cretaceous Western Interior and Gulf Coast zoogeographic provinces) from conformably underlying strata suggest that the fauna is of late Campanian age, probably correlative with Judithian assemblages of the Western Interior. A Judithian “age” for the fauna is further supported by its mammal and theropod assemblages, and by the faunas of overlying deposits. The previously reported diversity of the Aguja Formation, which we summarize, is significantly enriched by this new fauna. The fauna also fills a major gap in the biogeography of Campanian terrestrial vertebrates. Notable occurrences in the Terlingua local fauna include the therian mammal Gallolestes, previously known only from Baja California, and a hitherto unrecorded type of primitive ‘tribothere.’ At least 4 marsupial and 6 multituberculate taxa are present, several of which represent new taxa. Squamates comprise at least 10 taxa, including xenosaurs, necrosaurs, glyptosaurines, scincids, teiids, and a snake, several of which represent new taxa. In addition, the fauna includes at least 7 dinosaurs, 1 pterosaur, 2 crocodylomorphs, 3 turtles, 3 lissamphibians, 3 actinopterygians, and 8 chondrichthyans. Wood, amber, leaves, seeds, pollen, molluscs, and dinoflagellates are also preserved. The fauna is not strictly comparable to others from the Western Interior. It includes taxa that are either endemic or otherwise known only from relatively low latitudes, indicating an appreciable degree of latitudinal differentiation among Campanian terrestrial faunas bordering the Western Interior seaway.

@article{doi10108002724634199210011475,
    author = "Rowe, Timothy B. and Cifelli, Richard L. and Lehman, Thomas M. and Weil, Anne",
    title = "The Campanian Terlingua local fauna, with a summary of other vertebrates from the Aguja Formation, Trans-Pecos Texas",
    year = "1992",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT The Terlingua local fauna is a rich assemblage of predominantly terrestrial micro vertebrates from the Upper Cretaceous Aguja Formation of Trans-Pecos Texas. Marine invertebrates (which include elements of both Cretaceous Western Interior and Gulf Coast zoogeographic provinces) from conformably underlying strata suggest that the fauna is of late Campanian age, probably correlative with Judithian assemblages of the Western Interior. A Judithian “age” for the fauna is further supported by its mammal and theropod assemblages, and by the faunas of overlying deposits. The previously reported diversity of the Aguja Formation, which we summarize, is significantly enriched by this new fauna. The fauna also fills a major gap in the biogeography of Campanian terrestrial vertebrates. Notable occurrences in the Terlingua local fauna include the therian mammal Gallolestes, previously known only from Baja California, and a hitherto unrecorded type of primitive ‘tribothere.’ At least 4 marsupial and 6 multituberculate taxa are present, several of which represent new taxa. Squamates comprise at least 10 taxa, including xenosaurs, necrosaurs, glyptosaurines, scincids, teiids, and a snake, several of which represent new taxa. In addition, the fauna includes at least 7 dinosaurs, 1 pterosaur, 2 crocodylomorphs, 3 turtles, 3 lissamphibians, 3 actinopterygians, and 8 chondrichthyans. Wood, amber, leaves, seeds, pollen, molluscs, and dinoflagellates are also preserved. The fauna is not strictly comparable to others from the Western Interior. It includes taxa that are either endemic or otherwise known only from relatively low latitudes, indicating an appreciable degree of latitudinal differentiation among Campanian terrestrial faunas bordering the Western Interior seaway.",
    url = "https://doi.org/10.1080/02724634.1992.10011475",
    doi = "10.1080/02724634.1992.10011475",
    openalex = "W2085184837",
    references = "doi101016003101828790040x, doi101016003101829090110s, doi101017cbo9780511608377011, doi101126science11282807, doi1023071443203, doi1023071484559, doi103133pp151, doi105281zenodo16226902, openalexw1539913220, openalexw1826760900, openalexw2474977981, openalexw337536883"
}

The lithostratigraphic interval between the Taber and Lethbridge coal zones in the upper portion of the nonmarine Judith River Group of southeastern Alberta is divisible into two lithostratigraphic units separated by a regionally extensive and diachronous discontinuity. The lower unit, referred to here as the Oldman Formation, is characterized by very fine grained to fine-grained sandstones that contain fewer than 2% volcanic rock fragments; sandstone bodies with numerous sets of horizontally stratified sandstone, showing little or no evidence of lateral accretion; siliceous paleosols (ganisters); and a relatively high gamma-ray signal in the upper half of the formation. The Oldman Formation comprises deposits of a low-sinuosity, perhaps ephemeral fluvial system that originated in the southern Cordillera of Canada and northern Montana and flowed northeastward, perpendicular to the axis of the Alberta Basin.The upper unit is assigned to a new formation, the Dinosaur Park Formation, and is characterized by fine- to medium-grained sandstones with up to 10% volcanic rock fragments; sandstone bodies that exhibit lateral-accretion surfaces in the form of inclined heterolithic stratification; numerous articulated dinosaurs and dinosaur bone beds; and a relatively low gamma-ray signal in the lower half of the formation. The Dinosaur Park Formation comprises deposits of a high-sinuosity, fluvial-to-estuarine system that originated in the north and central Cordillera and flowed southeastward, subparallel to the axis of the Alberta Basin. 40 Ar/ 39 Ar and K–Ar dating of Judith River Group bentonites shows that the contact between the Oldman and Dinosaur Park formations becomes younger toward the south and southeast. These data also demonstrate that the Dinosaur Park Formation clastics migrated southeastward at a rate of approximately 130–140 km/Ma, gradually overstepping the Oldman Formation elastics.The widely recognized north-to-south increase in intensity of overthrust loading along the western margin of the Alberta Basin during the Late Cretaceous is thought to be responsible for (i) differences in accommodation space for the proximal portions of the Oldman and Dinosaur Park formations, and (ii) the establishment of a southerly tilt in the Alberta Basin leading to the southeastward migration of the Dinosaur Park Formation elastics. In the northern portion of the basin, relatively lower rates of subsidence, combined with periods of isostatic rebound in the foredeep, resulted in the southeastward migration of Dinosaur Park Formation elastics as sediment input exceeded accommodation space. In the southern portion of the basin, relatively higher rates of subsidence and little isostatic rebound acted to trap coarse-grained Oldman Formation elastics in the foredeep and may have led to periods of sediment starvation in more distal portions of the basin. An inferred lower depositional slope associated with the Dinosaur Park Formation (relative to the Oldman Formation) is thought to have resulted from gradual loading of the basin as Dinosaur Park Formation elastics migrated southeastward or some form of tectonically induced subsidence.

@article{doi101139e93016,
    author = "Eberth, David A. and Hamblin, A P",
    title = "Tectonic, stratigraphic, and sedimentologic significance of a regional discontinuity in the upper Judith River Group (Belly River wedge) of southern Alberta, Saskatchewan, and northern Montana",
    year = "1993",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The lithostratigraphic interval between the Taber and Lethbridge coal zones in the upper portion of the nonmarine Judith River Group of southeastern Alberta is divisible into two lithostratigraphic units separated by a regionally extensive and diachronous discontinuity. The lower unit, referred to here as the Oldman Formation, is characterized by very fine grained to fine-grained sandstones that contain fewer than 2\% volcanic rock fragments; sandstone bodies with numerous sets of horizontally stratified sandstone, showing little or no evidence of lateral accretion; siliceous paleosols (ganisters); and a relatively high gamma-ray signal in the upper half of the formation. The Oldman Formation comprises deposits of a low-sinuosity, perhaps ephemeral fluvial system that originated in the southern Cordillera of Canada and northern Montana and flowed northeastward, perpendicular to the axis of the Alberta Basin.The upper unit is assigned to a new formation, the Dinosaur Park Formation, and is characterized by fine- to medium-grained sandstones with up to 10\% volcanic rock fragments; sandstone bodies that exhibit lateral-accretion surfaces in the form of inclined heterolithic stratification; numerous articulated dinosaurs and dinosaur bone beds; and a relatively low gamma-ray signal in the lower half of the formation. The Dinosaur Park Formation comprises deposits of a high-sinuosity, fluvial-to-estuarine system that originated in the north and central Cordillera and flowed southeastward, subparallel to the axis of the Alberta Basin. 40 Ar/ 39 Ar and K–Ar dating of Judith River Group bentonites shows that the contact between the Oldman and Dinosaur Park formations becomes younger toward the south and southeast. These data also demonstrate that the Dinosaur Park Formation clastics migrated southeastward at a rate of approximately 130–140 km/Ma, gradually overstepping the Oldman Formation elastics.The widely recognized north-to-south increase in intensity of overthrust loading along the western margin of the Alberta Basin during the Late Cretaceous is thought to be responsible for (i) differences in accommodation space for the proximal portions of the Oldman and Dinosaur Park formations, and (ii) the establishment of a southerly tilt in the Alberta Basin leading to the southeastward migration of the Dinosaur Park Formation elastics. In the northern portion of the basin, relatively lower rates of subsidence, combined with periods of isostatic rebound in the foredeep, resulted in the southeastward migration of Dinosaur Park Formation elastics as sediment input exceeded accommodation space. In the southern portion of the basin, relatively higher rates of subsidence and little isostatic rebound acted to trap coarse-grained Oldman Formation elastics in the foredeep and may have led to periods of sediment starvation in more distal portions of the basin. An inferred lower depositional slope associated with the Dinosaur Park Formation (relative to the Oldman Formation) is thought to have resulted from gradual loading of the basin as Dinosaur Park Formation elastics migrated southeastward or some form of tectonically induced subsidence.",
    url = "https://doi.org/10.1139/e93-016",
    doi = "10.1139/e93-016",
    openalex = "W2037483301"
}

An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.

@article{doi101126science2665186779,
    author = "Norell, Mark A. and Clark, James M. and Demberelyin, Dashzeveg and Rhinchen, Barsbold and Chiappe, Luis M. and Davidson, Amy R. and McKenna, Malcolm C. and Altangerel, Perle and Novacek, Michael J.",
    title = "A Theropod Dinosaur Embryo and the Affinities of the Flaming Cliffs Dinosaur Eggs",
    year = "1994",
    journal = "Science",
    abstract = "An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.",
    url = "https://doi.org/10.1126/science.266.5186.779",
    doi = "10.1126/science.266.5186.779",
    openalex = "W2086035298",
    references = "doi101002jmor1051000302, doi1010160195667191900155, doi10108002724634198710011638, doi10108002724634199510011250, doi101111j174966321940tb57047x, doi101139e93196, doi1023073514816, doi105281zenodo16171435, openalexw2131558500, openalexw633579066, sues1977dentaries"
}

Four valid species of trionychine trionychid turtles are recognized from the Upper Cretaceous (mid-Campanian; Judithian) Judith River Group, western North America. Cladistic analysis of extant and Judith River Group trionychines supports referral of three fossil species to Aspideretoides gen. nov. and one fossil species to Apalone, the genus of extant North American trionychines. The taxonomic diversity of Judith River Group trionychids is less than that of younger Maastrichtian and Paleocene assemblages from the Western Interior, largely because of the absence of plastomenine trionychids in the Judith River Group assemblage.

@article{doi101139e95053,
    author = "Gardner, James D. and Russell, Anthony P. and Brinkman, Donald B.",
    title = "Systematics and taxonomy of soft-shelled turtles (Family Trionychidae) from the Judith River Group (mid-Campanian) of North America",
    year = "1995",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Four valid species of trionychine trionychid turtles are recognized from the Upper Cretaceous (mid-Campanian; Judithian) Judith River Group, western North America. Cladistic analysis of extant and Judith River Group trionychines supports referral of three fossil species to Aspideretoides gen. nov. and one fossil species to Apalone, the genus of extant North American trionychines. The taxonomic diversity of Judith River Group trionychids is less than that of younger Maastrichtian and Paleocene assemblages from the Western Interior, largely because of the absence of plastomenine trionychids in the Judith River Group assemblage.",
    url = "https://doi.org/10.1139/e95-053",
    doi = "10.1139/e95-053",
    openalex = "W2079676097",
    references = "doi105281zenodo1048846"
}

New choristoderan fossils from the Late Cretaceous and Palaeocene of Alberta and Saskatchewan, Canada, are described: incomplete maxillae and dentaries from the Upper Cretaceous Oldman Formation, Alberta, extend the range of the primitive Cteniogenys from the Jurassic in the North American Western Interior; an incomplete dentary from the Palaeocene Ravenscrag Formation, Saskatchewan, comprises the first occurrence of the crocodile-like Simoedosaurus in Canada and the earliest record of the genus; well-preserved skulls and mandibles from the Oldman and Horseshoe Canyon formations, Alberta, document a new species of Champsosaurus and clarify the status of previously known species of the genus. New information about Asian choristoderes supports a Tchoiria-(Ikechosaurus + Simoedosaurus) relationship, contrary to previous work. Choristoderes share no convincing synapomorphies with either Lepidosauromorpha or Archosauromorpha, but occupy a more basal position within Diapsida, possibly as a sister-taxon with Neodiapsida (Younginiformes + Sauria).

@article{doi101111j109636421998tb00580x,
    author = "Gao, Ke‐Qin and Fox, Richard C.",
    title = "New choristoderes (Reptilia: Diapsida) from the Upper Cretaceous and Palaeocene, Alberta and Saskatchewan, Canada, and phylogenetic relationships of Choristodera",
    year = "1998",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "New choristoderan fossils from the Late Cretaceous and Palaeocene of Alberta and Saskatchewan, Canada, are described: incomplete maxillae and dentaries from the Upper Cretaceous Oldman Formation, Alberta, extend the range of the primitive Cteniogenys from the Jurassic in the North American Western Interior; an incomplete dentary from the Palaeocene Ravenscrag Formation, Saskatchewan, comprises the first occurrence of the crocodile-like Simoedosaurus in Canada and the earliest record of the genus; well-preserved skulls and mandibles from the Oldman and Horseshoe Canyon formations, Alberta, document a new species of Champsosaurus and clarify the status of previously known species of the genus. New information about Asian choristoderes supports a Tchoiria-(Ikechosaurus + Simoedosaurus) relationship, contrary to previous work. Choristoderes share no convincing synapomorphies with either Lepidosauromorpha or Archosauromorpha, but occupy a more basal position within Diapsida, possibly as a sister-taxon with Neodiapsida (Younginiformes + Sauria).",
    url = "https://doi.org/10.1111/j.1096-3642.1998.tb00580.x",
    doi = "10.1111/j.1096-3642.1998.tb00580.x",
    openalex = "W2087896569",
    references = "doi105281zenodo1048846"
}

@article{doi1016690883135120010160482ttoaco20co2,
    author = "Ryan, Michael J. and Russell, Anthony P. and Eberth, David A. and Currie, Philip J.",
    title = "The Taphonomy of a Centrosaurus (Ornithischia: Certopsidae) Bone Bed from the Dinosaur Park Formation (Upper Campanian), Alberta, Canada, with Comments on Cranial Ontogeny",
    year = "2001",
    journal = "Palaios",
    url = "https://doi.org/10.1669/0883-1351(2001)016<0482:ttoaco>2.0.co;2",
    doi = "10.1669/0883-1351(2001)016<0482:ttoaco>2.0.co;2",
    openalex = "W2179225693",
    references = "brinkman1990paleooecology, doi1010160031018288900855, doi101016003101829090202i, doi101017s0094837300005820, doi101038114085a0, doi101038282296a0, doi101093nqs5vi146318i, doi101111j109636421997tb00340x, doi101126science11282807, doi101139e93016, doi101306c1ea47bb16c911d78645000102c1865d, doi102113gsrocky8specialpaper11, doi1023071296618, doi1023072531613, doi1023075209, doi105962bhlpart22969, eberth1990stratigraphy, openalexw2259418280, openalexw2591879035, openalexw568618627, parrish1987late"
}

ABSTRACT Theropod teeth are taxonomically diagnostic components of dinosaur assemblages. Seventy teeth have been recovered from six different localities in the Kogosukruk Tongue of the Prince Creek Formation (Upper Cretaceous) of the North Slope of Alaska. This assemblage of teeth shows slightly less diversity compared to well documented assemblages of teeth from the slightly older Judith River Formation of south-central Montana, the Aguja Formation of west Texas, and the Hell Creek Formation of eastern Montana. In addition, in contrast to the Judith River Formation assemblage of teeth in south-central Montana, the teeth assigned to Troodon dominated the Alaskan assemblage. The dominance of Troodon is attributed to adaptation by this theropod to low light conditions while overwintering at a high paleolatitude.

@article{doi1016710272463420000200675ttftpc20co2,
    author = "Fiorillo, Anthony R. and Gangloff, Roland A.",
    title = "Theropod teeth from the Prince Creek Formation (Cretaceous) of northern Alaska, with speculations on Arctic Dinosaur paleoecology",
    year = "2001",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Theropod teeth are taxonomically diagnostic components of dinosaur assemblages. Seventy teeth have been recovered from six different localities in the Kogosukruk Tongue of the Prince Creek Formation (Upper Cretaceous) of the North Slope of Alaska. This assemblage of teeth shows slightly less diversity compared to well documented assemblages of teeth from the slightly older Judith River Formation of south-central Montana, the Aguja Formation of west Texas, and the Hell Creek Formation of eastern Montana. In addition, in contrast to the Judith River Formation assemblage of teeth in south-central Montana, the teeth assigned to Troodon dominated the Alaskan assemblage. The dominance of Troodon is attributed to adaptation by this theropod to low light conditions while overwintering at a high paleolatitude.",
    url = "https://doi.org/10.1671/0272-4634(2000)020[0675:ttftpc]2.0.co;2",
    doi = "10.1671/0272-4634(2000)020[0675:ttftpc]2.0.co;2",
    openalex = "W2142364154",
    references = "doi101017s0022336000018862, doi10108002724634199210011475"
}

@article{brinkman2002teleost,
    author = "BRINKMAN, DONALD B. and NEUMAN, A. G.",
    title = "TELEOST CENTRA FROM UPPERMOST JUDITH RIVER GROUP (DINOSAUR PARK FORMATION, CAMPANIAN) OF ALBERTA, CANADA",
    year = "2002",
    journal = "Journal of Paleontology",
    url = "https://doi.org/10.1666/0022-3360(2002)076<0138:tcfujr>2.0.co;2",
    doi = "10.1666/0022-3360(2002)076<0138:tcfujr>2.0.co;2",
    number = "1",
    openalex = "W2174405334",
    pages = "138-155",
    volume = "76",
    references = "brinkman1990paleooecology, doi101016b9780126709506500138, doi10108002724634199210011475, doi1010970000505319311100000026, doi101139e93016, doi1043249781315150932, eberth1990stratigraphy, openalexw193970361, openalexw337536883, openalexw568207017"
}

@article{doi1016660022336020020760138tcfujr20co2,
    author = "Brinkman, D. and Neuman, A.",
    title = "TELEOST CENTRA FROM UPPERMOST JUDITH RIVER GROUP (DINOSAUR PARK FORMATION, CAMPANIAN) OF ALBERTA, CANADA",
    year = "2002",
    journal = "Journal of Paleontology",
    url = "http://doc.rero.ch/record/14754/files/PAL\_E1882.pdf",
    doi = "10.1666/0022-3360(2002)076<0138:TCFUJR>2.0.CO;2",
    is_oa = "true",
    number = "1",
    pages = "138-155",
    semanticscholar_citation_count = "53",
    semanticscholar_id = "65ac7219226a269358386180a5507e5bb2c8bd2b",
    volume = "76"
}

A collection of over 1,700 small theropod teeth from the Judith River Group (Campanian;˜79.5–74 Ma) allows our understanding of the diversity and variation of small theropods in this assemblage to be refined. In addition to the previously recognized taxa, a series of morphologically distinct groups are recognized that may represent distinct taxa in some cases. Teeth with the Paronychodon-like features of a flat surface with longitudinal ridges on one side are resolved into a few discrete morphotypes. Two of these are included in Paronychodon lacustris and two additional morphotypes are hypothesized to represent distinct taxa, here referred to as?Dromaeosaurus morphotype A and Genus and species indet. A. The teeth of Paronychodon lacustris and?Dromaeosaurus morphotype A share a distinctive wear pattern that suggests tooth functioning involved contact between the flat surfaces of opposing teeth. Two species of Richardoestesia, R. gilmorei and R. isosceles, are present in the assemblage. Additionally, bird teeth are identified in the assemblage and are described in this review.Bivariate plots were used to document the variation in the theropod teeth, especially in the features that distinguish between Richardoestesia gilmorei, R. isosceles, Saurornitholestes, and Dromaeosaurus. Considerable overlap is present in all plots, so although the teeth are morphologically distinct, they are not easily distinguished by quantitative means.

@article{doi1016660022336020020760751stabtf20co2,
    author = "Sankey, Julia and Brinkman, Donald B. and Guenther, Merrilee F. and Currie, Philip J.",
    title = "SMALL THEROPOD AND BIRD TEETH FROM THE LATE CRETACEOUS (LATE CAMPANIAN) JUDITH RIVER GROUP, ALBERTA",
    year = "2002",
    journal = "Journal of Paleontology",
    abstract = "A collection of over 1,700 small theropod teeth from the Judith River Group (Campanian;˜79.5–74 Ma) allows our understanding of the diversity and variation of small theropods in this assemblage to be refined. In addition to the previously recognized taxa, a series of morphologically distinct groups are recognized that may represent distinct taxa in some cases. Teeth with the Paronychodon-like features of a flat surface with longitudinal ridges on one side are resolved into a few discrete morphotypes. Two of these are included in Paronychodon lacustris and two additional morphotypes are hypothesized to represent distinct taxa, here referred to as?Dromaeosaurus morphotype A and Genus and species indet. A. The teeth of Paronychodon lacustris and?Dromaeosaurus morphotype A share a distinctive wear pattern that suggests tooth functioning involved contact between the flat surfaces of opposing teeth. Two species of Richardoestesia, R. gilmorei and R. isosceles, are present in the assemblage. Additionally, bird teeth are identified in the assemblage and are described in this review.Bivariate plots were used to document the variation in the theropod teeth, especially in the features that distinguish between Richardoestesia gilmorei, R. isosceles, Saurornitholestes, and Dromaeosaurus. Considerable overlap is present in all plots, so although the teeth are morphologically distinct, they are not easily distinguished by quantitative means.",
    url = "https://doi.org/10.1666/0022-3360(2002)076<0751:stabtf>2.0.co;2",
    doi = "10.1666/0022-3360(2002)076<0751:stabtf>2.0.co;2",
    openalex = "W2180979585",
    references = "crossref1998encyclopedia, doi101017cbo9780511608377011, doi101017s247526300000091x, doi10103835047056, doi10108002724634199210011475, doi101126science11282807, doi101126science13234331023, doi102475ajss319111253, doi102475ajss321125417, doi105281zenodo16171435, doi105962bhltitle115853, openalexw337536883"
}

Currie, Philip J. (2003): Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Palaeontologica Polonica 48 (2): 191-226, DOI: 10.5281/zenodo.3725717, URL: https://www.app.pan.pl/archive/published/app48/app48-191.pdf

@article{doi105281zenodo3725717,
    author = "Currie, Philip J.",
    title = "Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada",
    year = "2003",
    journal = "reroDoc Digital Library",
    abstract = "Currie, Philip J. (2003): Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Palaeontologica Polonica 48 (2): 191-226, DOI: 10.5281/zenodo.3725717, URL: https://www.app.pan.pl/archive/published/app48/app48-191.pdf",
    url = "https://doi.org/10.5281/zenodo.3725717",
    doi = "10.5281/zenodo.3725717",
    openalex = "W2107092189",
    references = "carr1999craniofacial, crossref1976allosaurus, currie1985cranial, doi101017cbo9780511608377011, doi101038358059a0, doi10108002724634199510011574, doi10108002724634199710011027, doi10108002724634199910011161, doi101139e02083, doi1015468lnfamn, doi1015468yhxmzl, doi1023071292217, doi1023073514548, doi1034191b109, doi104095101672, doi105281zenodo1037529, doi105281zenodo1040973, doi105281zenodo1048848, doi105281zenodo814935, vonhuene1923carnivorous"
}

@article{doi101016jcretres200806007,
    author = "Longrich, Nick",
    title = "An ornithurine-dominated avifauna from the Belly River Group (Campanian, Upper Cretaceous) of Alberta, Canada",
    year = "2008",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2008.06.007",
    doi = "10.1016/j.cretres.2008.06.007",
    openalex = "W2060493575",
    references = "brinkman2002teleost, doi101038381226a0, doi101038nature03150, doi101073pnas0401892101, doi101086419764, doi101098rspb20011877, doi101126science27553031109, doi101126science27553031113, doi1012019781420064452, doi105860choice393984, doi105860choice435902, longrich2008a"
}

Fossils of a predatory dinosaur provide novel information about the evolution of unenlagiines, a poorly known group of dromaeosaurid theropods from Gondwana. The new dinosaur is the largest dromaeosaurid yet discovered in the Southern Hemisphere and depicts bizarre cranial and postcranial features. Its long and low snout bears numerous, small-sized conical teeth, a condition resembling spinosaurid theropods. Its short forearms depart from the characteristically long-armed condition of all dromaeosaurids and their close avian relatives. The new discovery amplifies the range of morphological disparity among unenlagiines, demonstrating that by the end of the Cretaceous this clade included large, short-armed forms alongside crow-sized, long-armed, possibly flying representatives. The new dinosaur is the youngest record of dromaeosaurids from Gondwana and represents a previously unrecognized lineage of large predators in Late Cretaceous dinosaur faunas mainly dominated by abelisaurid theropods.

@article{doi101098rspb20081554,
    author = "Novas, Fernando E. and Pol, Diego and Canale, Juan I. and Porfiri, Juan D. and Calvo, Jorge O.",
    title = "A bizarre Cretaceous theropod dinosaur from Patagonia and the evolution of Gondwanan dromaeosaurids",
    year = "2008",
    journal = "Proceedings of the Royal Society B Biological Sciences",
    abstract = "Fossils of a predatory dinosaur provide novel information about the evolution of unenlagiines, a poorly known group of dromaeosaurid theropods from Gondwana. The new dinosaur is the largest dromaeosaurid yet discovered in the Southern Hemisphere and depicts bizarre cranial and postcranial features. Its long and low snout bears numerous, small-sized conical teeth, a condition resembling spinosaurid theropods. Its short forearms depart from the characteristically long-armed condition of all dromaeosaurids and their close avian relatives. The new discovery amplifies the range of morphological disparity among unenlagiines, demonstrating that by the end of the Cretaceous this clade included large, short-armed forms alongside crow-sized, long-armed, possibly flying representatives. The new dinosaur is the youngest record of dromaeosaurids from Gondwana and represents a previously unrecognized lineage of large predators in Late Cretaceous dinosaur faunas mainly dominated by abelisaurid theropods.",
    url = "https://doi.org/10.1098/rspb.2008.1554",
    doi = "10.1098/rspb.2008.1554",
    openalex = "W2065351263",
    references = "doi101038nature03285, doi1022179revmacn688, doi102307jctvqc6gzx, doi105860choice434677, openalexw834136096"
}

The lithostratigraphic interval between the marine Puskwaskau Formation (Smoky Group, Santonian–Campanian) and the fluvial Scollard Formation (early Maastrichtian) in west-central Alberta and easternmost British Columbia (Canada) is represented by the nonmarine deposits of the Wapiti Formation. Its subdivision into regionally mappable stratigraphic units and the correlation of such units with the better known successions of central and southern Alberta are the main goals of this study. We present a detailed stratigraphic revision of the Wapiti Formation in the Grande Prairie region, where the entire succession crops out extensively and intensive oil and gas exploration activity provides excellent subsurface control. This study indicates that the Wapiti Formation consists in five stratigraphic units: their description has been based in particular on facies analysis and well-log signatures. In ascending order, units 1 to 5 record major differences in depositional architecture related to variation in accommodation and climatic conditions. Upper and lower contacts of these units are represented by regionally mappable subaerial unconformities or conformable facies contacts. Three major coal zones are identified within the Wapiti Formation, the Basal, Red Willow, and Cutbank: coals referred to these intervals have been documented in both outcrop and subsurface in the entire study area, thus representing a reliable tool for regional correlations. Furthermore, results presented here indicate that the maximum flooding surfaces of the Bearpaw seaway and the Drumheller Marine Tongue, both marine reference units in central and southern Alberta, lie, respectively, within coals of unit 3 and the Red Willow coal zone.

@article{doi101139e09020,
    author = "Fanti, Federico and Catuneanu, Octavian",
    title = "Stratigraphy of the Upper Cretaceous Wapiti Formation, west-central Alberta, Canada",
    year = "2009",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The lithostratigraphic interval between the marine Puskwaskau Formation (Smoky Group, Santonian–Campanian) and the fluvial Scollard Formation (early Maastrichtian) in west-central Alberta and easternmost British Columbia (Canada) is represented by the nonmarine deposits of the Wapiti Formation. Its subdivision into regionally mappable stratigraphic units and the correlation of such units with the better known successions of central and southern Alberta are the main goals of this study. We present a detailed stratigraphic revision of the Wapiti Formation in the Grande Prairie region, where the entire succession crops out extensively and intensive oil and gas exploration activity provides excellent subsurface control. This study indicates that the Wapiti Formation consists in five stratigraphic units: their description has been based in particular on facies analysis and well-log signatures. In ascending order, units 1 to 5 record major differences in depositional architecture related to variation in accommodation and climatic conditions. Upper and lower contacts of these units are represented by regionally mappable subaerial unconformities or conformable facies contacts. Three major coal zones are identified within the Wapiti Formation, the Basal, Red Willow, and Cutbank: coals referred to these intervals have been documented in both outcrop and subsurface in the entire study area, thus representing a reliable tool for regional correlations. Furthermore, results presented here indicate that the maximum flooding surfaces of the Bearpaw seaway and the Drumheller Marine Tongue, both marine reference units in central and southern Alberta, lie, respectively, within coals of unit 3 and the Red Willow coal zone.",
    url = "https://doi.org/10.1139/e09-020",
    doi = "10.1139/e09-020",
    openalex = "W2134474332",
    references = "doi101006cres19941022, doi101016jpalaeo200902007, doi1035767gscpgbull444654, doi1035767gscpgbull452155"
}

New material of borioteiioidean lizards (Squamata: Scincomorpha) from west-central Alberta, Canada, represent\nthe first and northernmost record of multiple articulated skull elements from the Cretaceous of North America. Specimens\nwere recovered from the fluvial beds of the Wapiti Formation (Campanian) within a bentonitic paleosol exposed at\nthe Kleskun Hill Park, east of the city of Grande Prairie. Such beds accumulated during the maximum transgression of the\nBearpaw Seaway (73–74 Ma), thus providing crucial information on lizard faunas during a time interval represented in most\nof coeval North American deposits by marine strata. Cranial material ascribed to Socognathus unicuspis give the occasion for\na revision of the taxon with respect to osteologically better-known Polyglyphanodon sternbergi from the Late Cretaceous of\nUtah as well as a comparison with several lizards reported from coeval strata of Mongolia. Furthermore, a new scincomorphan\nlizard, Kleskunsaurus grandeprairiensis, gen. et sp. nov., is described. Socognathus unicuspis is assigned to Chamopsiidae,\ntaxon nov., which also includes Chamops, Leptochamops, and several other morphologically similar taxa from the Cretaceous\nof North America.

@article{doi101080027246342010483539,
    author = "Nydam, Randall L. and Caldwell, Michael W. and Fanti, Federico",
    title = "Borioteiioidean lizard skulls from Kleskun Hill (Wapiti Formation; upper Campanian), west-central Alberta, Canada",
    year = "2010",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "New material of borioteiioidean lizards (Squamata: Scincomorpha) from west-central Alberta, Canada, represent\nthe first and northernmost record of multiple articulated skull elements from the Cretaceous of North America. Specimens\nwere recovered from the fluvial beds of the Wapiti Formation (Campanian) within a bentonitic paleosol exposed at\nthe Kleskun Hill Park, east of the city of Grande Prairie. Such beds accumulated during the maximum transgression of the\nBearpaw Seaway (73–74 Ma), thus providing crucial information on lizard faunas during a time interval represented in most\nof coeval North American deposits by marine strata. Cranial material ascribed to Socognathus unicuspis give the occasion for\na revision of the taxon with respect to osteologically better-known Polyglyphanodon sternbergi from the Late Cretaceous of\nUtah as well as a comparison with several lizards reported from coeval strata of Mongolia. Furthermore, a new scincomorphan\nlizard, Kleskunsaurus grandeprairiensis, gen. et sp. nov., is described. Socognathus unicuspis is assigned to Chamopsiidae,\ntaxon nov., which also includes Chamops, Leptochamops, and several other morphologically similar taxa from the Cretaceous\nof North America.",
    url = "https://doi.org/10.1080/02724634.2010.483539",
    doi = "10.1080/02724634.2010.483539",
    openalex = "W1997084876",
    references = "doi104095105060"
}

Microfossil bonebeds are multi-individual accumulations of disarticulated and dissociated vertebrate hardparts dominated by elements in the millimeter to centimeter size range (≤75% of bioclasts ≤5 cm maximum dimension). Modes of accumulation are often difficult to decipher from reports in the literature, although predatory (scatological) and fluvial/hydraulic origins are typically proposed. We studied the sedimentology and taphonomy of 27 microfossil bonebeds in the Campanian Judith River Formation of Montana in order to reconstruct formative histories. Sixteen of the bonebeds examined are hosted by fine-grained facies that accumulated in low-energy aquatic settings (pond/lake microfossil bonebeds). Eleven of the bonebeds are embedded in sandstones that accumulated in ancient fluvial settings (channel-hosted microfossil bonebeds). In lieu of invoking separate pathways to accumulation based on facies distinctions, we present a model that links the accumulation of bioclasts in the two facies. We propose that vertebrate material initially accumulates to fossiliferous levels in ponds/lakes and is later reworked and redeposited as channel-hosted assemblages. This interpretation is grounded in reasonable expectations of lacustrine and fluvial depositional systems and supported by taphonomic data. Moreover, it is consistent with faunal data that indicate that channel-hosted assemblages and pond/lake assemblages are similar with regard to presence/absence and rank-order abundance of taxa. This revised model of bonebed formation has significant implications for studies of vertebrate paleoecology that hinge on analyses of faunal data recovered from vertebrate microfossil assemblages. Pond/lake microfossil bonebeds in the Judith River record are preserved in situ at the scale of the local paleoenvironment, with no indication of postmortem transport into or out of the life habitat. Moreover, they are time-averaged samples of their source communities, which increases the likelihood of capturing both ecologically abundant species and more rare or transient members of the paleocommunity. These attributes make pond/lake microfossil bonebeds excellent targets for paleoecological studies that seek to reconstruct overall community membership and structure. In contrast, channel-hosted microfossil bonebeds in the Judith River record are out of place from a paleoenvironmental perspective because they are reworked from preexisting pond/lake assemblages and redeposited in younger channel facies. However, despite a history of exhumation and redeposition, channel-hosted microfossil bonebeds are preserved in relatively close spatial proximity to original source beds. This taphonomic reconstruction is counter to the commonly held view that microfossil bonebeds are biased samples that have experienced long-distance transport and significant hydrodynamic sorting.

@article{doi1016660094837336180,
    author = "Rogers, Raymond R. and Brady, Mara",
    title = "Origins of microfossil bonebeds: insights from the Upper Cretaceous Judith River Formation of north-central Montana",
    year = "2010",
    journal = "Paleobiology",
    abstract = "Microfossil bonebeds are multi-individual accumulations of disarticulated and dissociated vertebrate hardparts dominated by elements in the millimeter to centimeter size range (≤75\% of bioclasts ≤5 cm maximum dimension). Modes of accumulation are often difficult to decipher from reports in the literature, although predatory (scatological) and fluvial/hydraulic origins are typically proposed. We studied the sedimentology and taphonomy of 27 microfossil bonebeds in the Campanian Judith River Formation of Montana in order to reconstruct formative histories. Sixteen of the bonebeds examined are hosted by fine-grained facies that accumulated in low-energy aquatic settings (pond/lake microfossil bonebeds). Eleven of the bonebeds are embedded in sandstones that accumulated in ancient fluvial settings (channel-hosted microfossil bonebeds). In lieu of invoking separate pathways to accumulation based on facies distinctions, we present a model that links the accumulation of bioclasts in the two facies. We propose that vertebrate material initially accumulates to fossiliferous levels in ponds/lakes and is later reworked and redeposited as channel-hosted assemblages. This interpretation is grounded in reasonable expectations of lacustrine and fluvial depositional systems and supported by taphonomic data. Moreover, it is consistent with faunal data that indicate that channel-hosted assemblages and pond/lake assemblages are similar with regard to presence/absence and rank-order abundance of taxa. This revised model of bonebed formation has significant implications for studies of vertebrate paleoecology that hinge on analyses of faunal data recovered from vertebrate microfossil assemblages. Pond/lake microfossil bonebeds in the Judith River record are preserved in situ at the scale of the local paleoenvironment, with no indication of postmortem transport into or out of the life habitat. Moreover, they are time-averaged samples of their source communities, which increases the likelihood of capturing both ecologically abundant species and more rare or transient members of the paleocommunity. These attributes make pond/lake microfossil bonebeds excellent targets for paleoecological studies that seek to reconstruct overall community membership and structure. In contrast, channel-hosted microfossil bonebeds in the Judith River record are out of place from a paleoenvironmental perspective because they are reworked from preexisting pond/lake assemblages and redeposited in younger channel facies. However, despite a history of exhumation and redeposition, channel-hosted microfossil bonebeds are preserved in relatively close spatial proximity to original source beds. This taphonomic reconstruction is counter to the commonly held view that microfossil bonebeds are biased samples that have experienced long-distance transport and significant hydrodynamic sorting.",
    url = "https://doi.org/10.1666/0094-8373-36.1.80",
    doi = "10.1666/0094-8373-36.1.80",
    openalex = "W1991303628",
    references = "doi101016003101829190016k, doi1010160169555x91900278, doi101016c20090021126, doi101016s0037073887800064, doi101017s0094837300005820, doi101038142234b0, doi101046j15298817200137602x, doi101146annurevearth32101802120201, doi102113gsrocky8specialpaper11, doi1023073514687, doi105281zenodo1048846, fiorillo2000taphonomy, lofgren1990reworking, openalexw2912219260"
}

Outcrop exposures and high-resolution subcrop data allow the description and mapping of four stratigraphic discontinuities in the fully nonmarine strata of the Campanian–Maastrichtian Wapiti Formation (Western Interior foreland basin, Alberta, Canada). This framework defines four unconformity-bounded depositional sequences (A–D), based on sequence stratigraphic methodology, well-log patterns, and facies analysis. In ascending order, sequence A records the transition from the underlying marine facies of the Puskwaskau Formation into the Wapiti fluvial facies, and consists of strongly progradational and aggradational stacking patterns. Sequences B and C show a similar pattern of basal amalgamated channelfill deposits that grade upwards into floodplain-dominated strata. Finally, sequence D is dominated by channelized sediments and extensive overbank facies. An aggradational stacking pattern suggests deposition under high-accommodation conditions. Maximum flooding surfaces are interpreted within fine-grained deposits in the upper portions of sequences C and D. They are tied to regionally extensive coals that accumulated more than 250 km away from the coeval shoreline. This study provides new evidence that major coal seams may represent the extension of marine maximum flooding surfaces into the downstream-controlled fluvial realm. Furthermore, the new stratigraphic framework of subaerial unconformities and maximum flooding surfaces provides the means of subdividing the previously undifferentiated fully nonmarine Wapiti Formation into depositional sequences and component systems tracts.

@article{doi102110jsr2010033,
    author = "Fanti, Federico and Catuneanu, Octavian",
    title = "Fluvial Sequence Stratigraphy: The Wapiti Formation, West-Central Alberta, Canada",
    year = "2010",
    journal = "Journal of Sedimentary Research",
    abstract = "Outcrop exposures and high-resolution subcrop data allow the description and mapping of four stratigraphic discontinuities in the fully nonmarine strata of the Campanian–Maastrichtian Wapiti Formation (Western Interior foreland basin, Alberta, Canada). This framework defines four unconformity-bounded depositional sequences (A–D), based on sequence stratigraphic methodology, well-log patterns, and facies analysis. In ascending order, sequence A records the transition from the underlying marine facies of the Puskwaskau Formation into the Wapiti fluvial facies, and consists of strongly progradational and aggradational stacking patterns. Sequences B and C show a similar pattern of basal amalgamated channelfill deposits that grade upwards into floodplain-dominated strata. Finally, sequence D is dominated by channelized sediments and extensive overbank facies. An aggradational stacking pattern suggests deposition under high-accommodation conditions. Maximum flooding surfaces are interpreted within fine-grained deposits in the upper portions of sequences C and D. They are tied to regionally extensive coals that accumulated more than 250 km away from the coeval shoreline. This study provides new evidence that major coal seams may represent the extension of marine maximum flooding surfaces into the downstream-controlled fluvial realm. Furthermore, the new stratigraphic framework of subaerial unconformities and maximum flooding surfaces provides the means of subdividing the previously undifferentiated fully nonmarine Wapiti Formation into depositional sequences and component systems tracts.",
    url = "https://doi.org/10.2110/jsr.2010.033",
    doi = "10.2110/jsr.2010.033",
    openalex = "W2124677724",
    references = "doi1010160031018270900945, doi101016jpalaeo200902007, doi1035767gscpgbull444654, doi1035767gscpgbull452155"
}

ABSTRACT Currently known from the early Campanian to late Maastrichtian, Prognathodon constitutes a group of mosasaurine mosasaurs that typically possessed massive jaws. Only four articulated skulls are known to date and the information concerning their postcrania remains minimal. Moreover, the early to middle Campanian specimens of the taxon are extremely rare and fragmentary. Two new specimens of Prognathodon overtoni from the early late Campanian (ca. 74.5 Ma) Bearpaw Formation exposed near Welling, southern Alberta, Canada, provide the first fully articulated skeletons of the genus. Detailed morphological assessment of these and pre-existing specimens indicates that many cranial characters are shared between P. overtoni and the generic type P. solvayi from the early Maastrichtian, including (1) short premaxillary-maxillary suture; (2) short triangular frontal with marked anterior constriction; and (3) distinct, blind-ended median opening on medullary floor of basioccipital. These are interpreted as generically diagnostic characters, and the first character in particular distinguishes Prognathodon from Liodon and other long-snouted mosasaurines. The postcranium of P. overtoni is lightly built, and differs very little from that of Clidastes, a basal mosasaurine. Marginal teeth are carinate with fine crenulations, indicating their proposed opportunistic predatory behavior. Additionally, most of the fully erupted teeth exhibit a similar degree of apical wear, which is interpreted as indicating that the taxon regularly handled prey items that involved crunching. To augment these dietary inferences, gut contents from one of the new specimens include fragments of a large and a small fish, a sea turtle, and possibly a cephalopod.

@article{doi101080027246342011601714,
    author = "Konishi, Takuya and Brinkman, Donald B. and Massare, Judy A. and Caldwell, Michael W.",
    title = "New exceptional specimens of Prognathodon overtoni (Squamata, Mosasauridae) from the upper Campanian of Alberta, Canada, and the systematics and ecology of the genus",
    year = "2011",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Currently known from the early Campanian to late Maastrichtian, Prognathodon constitutes a group of mosasaurine mosasaurs that typically possessed massive jaws. Only four articulated skulls are known to date and the information concerning their postcrania remains minimal. Moreover, the early to middle Campanian specimens of the taxon are extremely rare and fragmentary. Two new specimens of Prognathodon overtoni from the early late Campanian (ca. 74.5 Ma) Bearpaw Formation exposed near Welling, southern Alberta, Canada, provide the first fully articulated skeletons of the genus. Detailed morphological assessment of these and pre-existing specimens indicates that many cranial characters are shared between P. overtoni and the generic type P. solvayi from the early Maastrichtian, including (1) short premaxillary-maxillary suture; (2) short triangular frontal with marked anterior constriction; and (3) distinct, blind-ended median opening on medullary floor of basioccipital. These are interpreted as generically diagnostic characters, and the first character in particular distinguishes Prognathodon from Liodon and other long-snouted mosasaurines. The postcranium of P. overtoni is lightly built, and differs very little from that of Clidastes, a basal mosasaurine. Marginal teeth are carinate with fine crenulations, indicating their proposed opportunistic predatory behavior. Additionally, most of the fully erupted teeth exhibit a similar degree of apical wear, which is interpreted as indicating that the taxon regularly handled prey items that involved crunching. To augment these dietary inferences, gut contents from one of the new specimens include fragments of a large and a small fish, a sea turtle, and possibly a cephalopod.",
    url = "https://doi.org/10.1080/02724634.2011.601714",
    doi = "10.1080/02724634.2011.601714",
    openalex = "W2095699852",
    references = "brinkman2002teleost, doi101016b978012155210750017x, doi101017cbo9780511536045020, doi101017s0016774600020965, doi10108002724634198710011647, doi101093nqs5vi146318i, doi1012063101, doi1023071292217, doi1023073514548, doi105860choice435902, doi105962bhltitle4911, doi105962bhltitle52081"
}

Brown, Caleb Marshall, Boyd, Clint A., Russell, Anthony P. (2011): A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America. Zoological Journal of the Linnean Society 163 (4): 1157-1198, DOI: 10.1111/j.1096-3642.2011.00735.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2011.00735.x

@article{doi101111j10963642201100735x,
    author = "Brown, Caleb M. and Boyd, Clint and Russell, Anthony P.",
    title = "A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America",
    year = "2011",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Brown, Caleb Marshall, Boyd, Clint A., Russell, Anthony P. (2011): A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America. Zoological Journal of the Linnean Society 163 (4): 1157-1198, DOI: 10.1111/j.1096-3642.2011.00735.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2011.00735.x",
    url = "https://doi.org/10.1111/j.1096-3642.2011.00735.x",
    doi = "10.1111/j.1096-3642.2011.00735.x",
    openalex = "W1502988646",
    references = "doi101038307360a0, doi101139e10005, doi1035767gscpgbull444654"
}

Abstract The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13–20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280–2100 ft) wide and 28 to 36 m (92–118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels.

@article{doi10130612131010111,
    author = "Hubbard, Stephen M. and Smith, Derald G. and Nielsen, Haley and Leckie, Dale A. and Fustic, Milovan and Spencer, Ronald J. and Bloom, Lorraine",
    title = "Seismic geomorphology and sedimentology of a tidally influenced river deposit, Lower Cretaceous Athabasca oil sands, Alberta, Canada",
    year = "2011",
    journal = "AAPG Bulletin",
    abstract = "Abstract The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13–20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280–2100 ft) wide and 28 to 36 m (92–118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels.",
    url = "https://doi.org/10.1306/12131010111",
    doi = "10.1306/12131010111",
    openalex = "W2160469173",
    references = "doi1010079783662010204, doi1010160037073880900524, doi101016jmarpetgeo200308003, doi101016s0037073887800064, doi101306212f7e4b2b2411d78648000102c1865d"
}

BACKGROUND: Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes. CONCLUSION/SIGNIFICANCE: Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.

@article{doi101371journalpone0024487,
    author = "Zanno, Lindsay E. and Varricchio, David J. and O’Connor, Patrick M. and Titus, Alan L. and Knell, Michael J.",
    title = "A New Troodontid Theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America",
    year = "2011",
    journal = "PLoS ONE",
    abstract = "BACKGROUND: Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes. CONCLUSION/SIGNIFICANCE: Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.",
    url = "https://doi.org/10.1371/journal.pone.0024487",
    doi = "10.1371/journal.pone.0024487",
    openalex = "W2075731101",
    references = "doi101002ar20986, doi101002sici109686441999081094563aidajpa1130co2x, doi101016jsedgeo200610001, doi101016s0006320796900622, doi101016s0748300703000604, doi101111j155856461985tb00420x, doi1012066481, doi101371journalpone0012292, doi101371journalpone0014329, doi1015468gcrned, doi1016710272463420050250897anotmf20co2, doi1023072408678, doi102307jctvqc6gzx, doi102475ajss319111253, doi105860choice362492, doi105962bhltitle115853, doi105962p339375, openalexw2611511275, openalexw3206657856, openalexw3215057009, wilson1985stenonychosaurus"
}

@article{doi101016jpalaeo201206024,
    author = "Mallon, Jordan C. and Evans, David C. and Ryan, Michael J. and Anderson, Jason S.",
    title = "Megaherbivorous dinosaur turnover in the Dinosaur Park Formation (upper Campanian) of Alberta, Canada",
    year = "2012",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2012.06.024",
    doi = "10.1016/j.palaeo.2012.06.024",
    openalex = "W2023998490",
    references = "brinkman1990paleooecology, doi1010160031018288900855, doi1010160098300487900227, doi101016jcretres200501002, doi10108001621459196310500845, doi101111j144299931993tb00438x, doi101111j146981371912tb05611x, doi101139e05029, doi101139e09050, doi101139e78109, doi101139e93016, doi101146annureves26110195002305, doi101371journalpone0012292, doi1016690883135120010160482ttoaco20co2, doi10167102724634200727373aarolm20co2, doi1023071412159, doi1023071932409, doi105281zenodo16435756, lehman1987late, openalexw2032279931, openalexw2183707334"
}

@article{doi101016jpalaeo201206027,
    author = "Brown, Caleb M. and Evans, David C. and Campione, Nicolás E. and O’Brien, Lorna J. and Eberth, David A.",
    title = "Evidence for taphonomic size bias in the Dinosaur Park Formation (Campanian, Alberta), a model Mesozoic terrestrial alluvial‐paralic system",
    year = "2012",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2012.06.027",
    doi = "10.1016/j.palaeo.2012.06.027",
    openalex = "W2079386558",
    references = "doi101007s1143001040949, doi1010160031018288900855, doi101016003101828890096x, doi101016jcretres200806007, doi101016jtree200504005, doi101017cbo9780511608551, doi101073pnas0606028103, doi10108002724634199510011575, doi101080027246342013746229, doi101093bioinformaticsbtg287, doi101093sysbio24137, doi101098rspb20091845, doi101111j109636421997tb00340x, doi101126science1116412, doi101126science1156963, doi101126science24148721441, doi101126science28454232137, doi101126science7701342, doi101144sp35813, doi101146annureves26110195002305, doi101186174170071060, doi101371journalpone0016574, doi101371journalpone0037122, doi1015468gcrned, doi1016690883135120010160482ttoaco20co2, doi1016710390290119, doi101890070037, doi105281zenodo1040973, doi105860choice331556, doi105860choice435902, doi107208chicago97802267237300010001, horner2011dinosaur, longrich2008a"
}

The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian-Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to ~8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (~3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate-polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm-temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the hallmark 'Gondwanan' fauna of South America and Africa may therefore reflect climate-driven provinciality, not vicariant evolution driven by continental fragmentation. However, vicariance may still be detected at lower phylogenetic levels.

@article{doi101371journalpone0037122,
    author = "Benson, Roger and Rich, Thomas H. and Vickers-Rich, Patricia and Hall, Mike",
    title = "Theropod Fauna from Southern Australia Indicates High Polar Diversity and Climate-Driven Dinosaur Provinciality",
    year = "2012",
    journal = "PLoS ONE",
    abstract = "The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian-Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to \textasciitilde 8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (\textasciitilde 3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate-polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm-temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the hallmark 'Gondwanan' fauna of South America and Africa may therefore reflect climate-driven provinciality, not vicariant evolution driven by continental fragmentation. However, vicariance may still be detected at lower phylogenetic levels.",
    url = "https://doi.org/10.1371/journal.pone.0037122",
    doi = "10.1371/journal.pone.0037122",
    openalex = "W2083980191",
    references = "carpenter2005the, crossref1976allosaurus, doi1010160012821x89900186, doi101016jtoxlet200611011, doi10103831635, doi101038416816a, doi10108002724634199910011178, doi101080147720192010488045, doi101126science13334591105, doi101126science28454232137, doi101139e05044, doi101590s000137652011000100008, doi105281zenodo13315375, doi105281zenodo16171435, doi105860choice331556, doi105860choice393984"
}

ABSTRACT Relative to large-bodied dinosaurs, the diversity of small-bodied dinosaurs from the Campanian of North America is poorly understood due to a lack of well-preserved skeletons. We document the first articulated remains, as well as the first cranial bones, of non-iguanodontian ornithopods from the Belly River Group of Alberta. The geologically oldest specimen consists of the posterior half of an articulated skeleton from the middle unit of the Oldman Formation and shares many anatomical features with the contemporaneous Orodromeus makelai and the older Oryctodromeus cubicularis. A second, younger specimen from the upper Oldman Formation is distinct from other ornithopods in having a reduced distal portion of the fibula that is fused to the anterior surface of the tibia; it is designated as the type of a new taxon, Albertadromeus syntarsus, gen. et sp. nov. Numerous isolated elements from small ornithopods from the Dinosaur Park Formation are also identified, but cannot be assigned to the generic level with confidence. Although small-bodied ornithopod material is rare, their known postcranial material outnumbers those of taphonomically equivalent and contemporaneous pachycephalosaurs, which are known to be abundant and diverse due to their robust and frequently recovered cranial domes. These findings suggest considerable undiscovered diversity of small-bodied ornithopods, and highlight biases against the preservation of small taxa in this system. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

@article{doi101080027246342013746229,
    author = "Brown, Caleb M. and Evans, David C. and Ryan, Michael J. and Russell, Anthony P.",
    title = "New data on the diversity and abundance of small-bodied ornithopods (Dinosauria, Ornithischia) from the Belly River Group (Campanian) of Alberta",
    year = "2013",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Relative to large-bodied dinosaurs, the diversity of small-bodied dinosaurs from the Campanian of North America is poorly understood due to a lack of well-preserved skeletons. We document the first articulated remains, as well as the first cranial bones, of non-iguanodontian ornithopods from the Belly River Group of Alberta. The geologically oldest specimen consists of the posterior half of an articulated skeleton from the middle unit of the Oldman Formation and shares many anatomical features with the contemporaneous Orodromeus makelai and the older Oryctodromeus cubicularis. A second, younger specimen from the upper Oldman Formation is distinct from other ornithopods in having a reduced distal portion of the fibula that is fused to the anterior surface of the tibia; it is designated as the type of a new taxon, Albertadromeus syntarsus, gen. et sp. nov. Numerous isolated elements from small ornithopods from the Dinosaur Park Formation are also identified, but cannot be assigned to the generic level with confidence. Although small-bodied ornithopod material is rare, their known postcranial material outnumbers those of taphonomically equivalent and contemporaneous pachycephalosaurs, which are known to be abundant and diverse due to their robust and frequently recovered cranial domes. These findings suggest considerable undiscovered diversity of small-bodied ornithopods, and highlight biases against the preservation of small taxa in this system. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP",
    url = "https://doi.org/10.1080/02724634.2013.746229",
    doi = "10.1080/02724634.2013.746229",
    openalex = "W2110252286",
    references = "doi101016003101829090202i, doi101016jtree200504005, doi101038114085a0, doi10108002724634199610011283, doi101086273307, doi101098rspl18870117, doi101111j10960031200800217x, doi101126science28454232137, doi101139e05029, doi101139e11017, doi1035767gscpgbull444654, doi105281zenodo3382461, eberth1990stratigraphy, openalexw1535663436, openalexw225597919, openalexw3215057009, openalexw616953834"
}

ABSTRACT The late Campanian–aged (= Judithian) squamates from the Terlingua Local Fauna of the Aguja Formation, southern Texas, includes four scincomorphans: a new taxon (Catactegenys solaster, gen. et sp. nov.), referable to Xantusiidae, that has massive teeth and tooth crown morphology similar to that of contogeniid lizards; an indeterminate scincomorphan (Apsgnathus triptodon, gen et sp. nov.) with robust teeth; and two unnamed scincomorphan morphotypes. Anguimorphans in the fauna include Odaxosaurus piger, cf. Parasaniwa wyomingensis, and a likely xenosaur. Ophidian jaw fragments confirm the presence of a snake in the fauna. The Aguja squamate assemblage is one of the most southerly of a series of paracontemporaneous squamate faunas extending from central Alberta to northern Mexico. Comparison of these faunas reveals that, although two taxa are endemic to the Aguja Formation, others show some latitudinal trends. Odaxosaurus and Parasaniwa are present in all well-sampled faunas from Alberta to Texas. The mammal-like Peneteius and snakes are found only in faunas from southern Utah to Mexico. Chamopsiids are only present from Alberta to New Mexico. The sole representatives of Contogeniidae and Xantusiidae are restricted to southern Utah and southern Texas, respectively. These hypotheses of distributional patterns must continue to be tested through ongoing investigations of all of the relevant faunas from the late Campanian of the Western Interior. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

@article{doi101080027246342013760467,
    author = "Nydam, Randall L. and Rowe, Timothy B. and Cifelli, Richard L.",
    title = "Lizards and snakes of the Terlingua Local Fauna (late Campanian), Aguja Formation, Texas, with comments on the distribution of paracontemporaneous squamates throughout the Western Interior of North America",
    year = "2013",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT The late Campanian–aged (= Judithian) squamates from the Terlingua Local Fauna of the Aguja Formation, southern Texas, includes four scincomorphans: a new taxon (Catactegenys solaster, gen. et sp. nov.), referable to Xantusiidae, that has massive teeth and tooth crown morphology similar to that of contogeniid lizards; an indeterminate scincomorphan (Apsgnathus triptodon, gen et sp. nov.) with robust teeth; and two unnamed scincomorphan morphotypes. Anguimorphans in the fauna include Odaxosaurus piger, cf. Parasaniwa wyomingensis, and a likely xenosaur. Ophidian jaw fragments confirm the presence of a snake in the fauna. The Aguja squamate assemblage is one of the most southerly of a series of paracontemporaneous squamate faunas extending from central Alberta to northern Mexico. Comparison of these faunas reveals that, although two taxa are endemic to the Aguja Formation, others show some latitudinal trends. Odaxosaurus and Parasaniwa are present in all well-sampled faunas from Alberta to Texas. The mammal-like Peneteius and snakes are found only in faunas from southern Utah to Mexico. Chamopsiids are only present from Alberta to New Mexico. The sole representatives of Contogeniidae and Xantusiidae are restricted to southern Utah and southern Texas, respectively. These hypotheses of distributional patterns must continue to be tested through ongoing investigations of all of the relevant faunas from the late Campanian of the Western Interior. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP",
    url = "https://doi.org/10.1080/02724634.2013.760467",
    doi = "10.1080/02724634.2013.760467",
    openalex = "W2091720836",
    references = "doi10108002724634199210011475, doi101086653688, doi103732ajb0900234, doi105962bhltitle115853, openalexw2246336267"
}

A high-resolution biostratigraphic analysis of 287 dinosaurian macrofossils and 138 bonebeds in the Edmonton Group (Upper Cretaceous) of southern Alberta provides evidence for at least three dinosaurian assemblage zones in the Horseshoe Canyon Formation (HCFm). From bottom to top the zones comprise unique assemblages of ornithischians and are named as follows: (1) Edmontosaurus regalis – Pachyrhinosaurus canadensis (lower zone); (2) Hypacrosaurus altispinus – Saurolophus osborni (middle zone); and (3) Eotriceratops xerinsularis (upper zone). Whereas the lower and middle zones are well defined and based on abundant specimens, the validity of the uppermost zone (E. xerinsularis) is tentative because it is based on a single specimen and the absence of dinosaur taxa from lower in section. The transition from the lower to the middle zone coincides with the replacement of a warm-and-wet saturated deltaic setting by a cooler, coastal-plain landscape, characterized by seasonal rainfall and better-drained substrates. Whereas changes in rainfall and substrate drainage appear to have influenced the faunal change, changes in mean annual temperature and proximity to shoreline appear to have had little influence on faunal change. We speculate that the faunal change between the middle and upper zones also resulted from a change in climate, with ornithischian dinosaurs responding to the re-establishment of wetter-and-warmer climates and poorly-drained substrates. Compared with the shorter-duration and climatically-consistent dinosaurian assemblage zones in the older Dinosaur Park Formation of southern Alberta, HCFm assemblage zones record long-term morphological stasis in dinosaurs. Furthermore, the coincidence of faunal and paleoenvironmental changes in the HCFm suggest climate-change-driven dinosaur migrations into and out of the region.

@article{doi101139cjes20120185,
    author = "Eberth, David A. and Evans, David C. and Brinkman, Donald B. and Therrien, François and Tanke, Darren H. and Russell, Loris S.",
    title = "Dinosaur biostratigraphy of the Edmonton Group (Upper Cretaceous), Alberta, Canada: evidence for climate influence",
    year = "2013",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "A high-resolution biostratigraphic analysis of 287 dinosaurian macrofossils and 138 bonebeds in the Edmonton Group (Upper Cretaceous) of southern Alberta provides evidence for at least three dinosaurian assemblage zones in the Horseshoe Canyon Formation (HCFm). From bottom to top the zones comprise unique assemblages of ornithischians and are named as follows: (1) Edmontosaurus regalis – Pachyrhinosaurus canadensis (lower zone); (2) Hypacrosaurus altispinus – Saurolophus osborni (middle zone); and (3) Eotriceratops xerinsularis (upper zone). Whereas the lower and middle zones are well defined and based on abundant specimens, the validity of the uppermost zone (E. xerinsularis) is tentative because it is based on a single specimen and the absence of dinosaur taxa from lower in section. The transition from the lower to the middle zone coincides with the replacement of a warm-and-wet saturated deltaic setting by a cooler, coastal-plain landscape, characterized by seasonal rainfall and better-drained substrates. Whereas changes in rainfall and substrate drainage appear to have influenced the faunal change, changes in mean annual temperature and proximity to shoreline appear to have had little influence on faunal change. We speculate that the faunal change between the middle and upper zones also resulted from a change in climate, with ornithischian dinosaurs responding to the re-establishment of wetter-and-warmer climates and poorly-drained substrates. Compared with the shorter-duration and climatically-consistent dinosaurian assemblage zones in the older Dinosaur Park Formation of southern Alberta, HCFm assemblage zones record long-term morphological stasis in dinosaurs. Furthermore, the coincidence of faunal and paleoenvironmental changes in the HCFm suggest climate-change-driven dinosaur migrations into and out of the region.",
    url = "https://doi.org/10.1139/cjes-2012-0185",
    doi = "10.1139/cjes-2012-0185",
    openalex = "W2157353435",
    references = "doi101016jpalaeo201206024, doi101016jpalaeo201206027, doi101017cbo9780511536045020, doi101098rspb20090352, doi101126science1177265, doi1011270078042120120020, doi101139e10005, doi101139e11017, doi101139e72031, doi101139e93016, doi10130683d923ed16c711d78645000102c1865d, doi101371journalpone0016574, doi101371journalpone0025186, doi104202app20110033, doi105281zenodo3725717, horner2011dinosaur, openalexw2989049194, sternberg1926notes"
}

Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate patterns of evolution and extinction in these groups and potentially others in greater detail than has previously been thought possible without more complete skeletal material.

@article{doi101371journalpone0054329,
    author = "Larson, Derek W. and Currie, Philip J.",
    title = "Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time",
    year = "2013",
    journal = "PLoS ONE",
    abstract = "Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate patterns of evolution and extinction in these groups and potentially others in greater detail than has previously been thought possible without more complete skeletal material.",
    url = "https://doi.org/10.1371/journal.pone.0054329",
    doi = "10.1371/journal.pone.0054329",
    openalex = "W2073560226",
    references = "carpenter2005the, crossref1998encyclopedia, doi1010029780470750711, doi101002ara20206, doi1010079780387217062, doi101016jpalaeo200902007, doi101017cbo9780511608377011, doi101098rspb20090352, doi101139e10005, doi101371journalpone0016574, doi101371journalpone0025186, doi1015468gcrned, doi1016660022336020010750208lcsdaf20co2, doi1016660022336020020760751stabtf20co2, doi105281zenodo3725717, doi105860choice393984, doi105860choice435902, horner2011dinosaur, openalexw2289748525, russell2002synopsis"
}

Few ankylosaurs are known from more than a single specimen, but the ankylosaurid Euoplocephalus tutus (from the Late Cretaceous of Alberta, Canada and Montana, USA) is represented by dozens of skulls and partial skeletons, and is therefore an important taxon for understanding intraspecific variation in ankylosaurs. Euoplocephalus is unusual compared to other dinosaurs from the Late Cretaceous of Alberta because it is recognized from the Dinosaur Park, Horseshoe Canyon, and Two Medicine formations. A comprehensive review of material attributed to Euoplocephalus finds support for the resurrection of its purported synonyms Anodontosaurus lambei and Scolosaurus cutleri, and the previously resurrected Dyoplosaurus acutosquameus. Anodontosaurus is found primarily in the Horseshoe Canyon Formation of Alberta and is characterized by ornamentation posterior to the orbits and on the first cervical half ring, and wide, triangular knob osteoderms. Euoplocephalus is primarily found in Megaherbivore Assemblage Zone 1 in the Dinosaur Park Formation of Alberta and is characterized by the absence of ornamentation posterior to the orbits and on the first cervical half ring, and keeled medial osteoderms on the first cervical half ring. Scolosaurus is found primarily in the Two Medicine Formation of Montana (although the holotype is from Dinosaur Provincial Park), and is characterized by long, back-swept squamosal horns, ornamentation posterior to the orbit, and low medial osteoderms on the first cervical half ring; Oohkotokia horneri is morphologically indistinguishable from Scolosaurus cutleri. Dyoplosaurus was previously differentiated from Euoplocephalus sensu lato by the morphology of the pelvis and pes, and these features also differentiate Dyoplosaurus from Anodontosaurus and Scolosaurus; a narrow tail club knob is probably also characteristic for Dyoplosaurus.

@article{doi101371journalpone0062421,
    author = "Arbour, Victoria M. and Currie, Philip J.",
    title = "Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA",
    year = "2013",
    journal = "PLoS ONE",
    abstract = "Few ankylosaurs are known from more than a single specimen, but the ankylosaurid Euoplocephalus tutus (from the Late Cretaceous of Alberta, Canada and Montana, USA) is represented by dozens of skulls and partial skeletons, and is therefore an important taxon for understanding intraspecific variation in ankylosaurs. Euoplocephalus is unusual compared to other dinosaurs from the Late Cretaceous of Alberta because it is recognized from the Dinosaur Park, Horseshoe Canyon, and Two Medicine formations. A comprehensive review of material attributed to Euoplocephalus finds support for the resurrection of its purported synonyms Anodontosaurus lambei and Scolosaurus cutleri, and the previously resurrected Dyoplosaurus acutosquameus. Anodontosaurus is found primarily in the Horseshoe Canyon Formation of Alberta and is characterized by ornamentation posterior to the orbits and on the first cervical half ring, and wide, triangular knob osteoderms. Euoplocephalus is primarily found in Megaherbivore Assemblage Zone 1 in the Dinosaur Park Formation of Alberta and is characterized by the absence of ornamentation posterior to the orbits and on the first cervical half ring, and keeled medial osteoderms on the first cervical half ring. Scolosaurus is found primarily in the Two Medicine Formation of Montana (although the holotype is from Dinosaur Provincial Park), and is characterized by long, back-swept squamosal horns, ornamentation posterior to the orbit, and low medial osteoderms on the first cervical half ring; Oohkotokia horneri is morphologically indistinguishable from Scolosaurus cutleri. Dyoplosaurus was previously differentiated from Euoplocephalus sensu lato by the morphology of the pelvis and pes, and these features also differentiate Dyoplosaurus from Anodontosaurus and Scolosaurus; a narrow tail club knob is probably also characteristic for Dyoplosaurus.",
    url = "https://doi.org/10.1371/journal.pone.0062421",
    doi = "10.1371/journal.pone.0062421",
    openalex = "W1975988440",
    references = "doi101016jpalaeo200902007, doi101016jpalaeo201206024, doi101080089129632012688589"
}

Caenagnathid theropods are a relatively common part of the theropod fauna in the Late Cretaceous of Asia and North America, but have not previously been described from the southernmost United States. Here, we describe caenagnathid fossils from the late Campanian Aguja Formation of West Texas, and revise the systematics of caenagnathids from the Campanian of North America. Caenagnathids from the late Campanian of Canada represent three species in three genera: Caenagnathus collinsi, Chirostenotes pergracilis and Leptorhynchos elegans gen. nov. Leptorhynchos is diagnosed by its small size, its short, deep mandible, and the upturned tip of the beak. A single caenagnathid is known from the late Campanian of Utah, Hagryphus giganteus. Two caenagnathid species occur in the Aguja Formation,?Chirostenotes sp. and Leptorhynchos gaddisi sp. nov. L. gaddisi differs from L. elegans in that the tip of the beak is narrower and less upturned. Phylogenetic analysis recovers Caenagnathidae and Oviraptoridae as monophyletic sister taxa. Within Caenagnathidae, the North American species seem to form a monophyletic assemblage, the Caenagnathinae, within which Chirostenotes and Caenagnathus form a clade to the exclusion of Leptorhynchos. The discovery of Chirostenotes gaddisi provides more evidence for the existence of a distinct dinosaurian fauna in southern North America during the Campanian. Furthermore, the Aguja fossils show that caenagnathids were widespread and highly diverse in the Late Cretaceous of North America. This diversity was maintained in two ways. First, variation in body size and beak shape suggests that diversity within formations is maintained by niche partitioning, in a way analogous to Darwin's finches. Second, diversity is maintained by high degree of endemism, with different species of caenagnathids occurring in different habitats.

@article{doi1033740140540102,
    author = "Longrich, Nicholas R. and Barnes, Ken and Clark, Scott and Millar, Larry",
    title = "Caenagnathidae from the Upper Campanian Aguja Formation of West Texas, and a Revision of the Caenagnathinae",
    year = "2013",
    journal = "Bulletin of the Peabody Museum of Natural History",
    abstract = "Caenagnathid theropods are a relatively common part of the theropod fauna in the Late Cretaceous of Asia and North America, but have not previously been described from the southernmost United States. Here, we describe caenagnathid fossils from the late Campanian Aguja Formation of West Texas, and revise the systematics of caenagnathids from the Campanian of North America. Caenagnathids from the late Campanian of Canada represent three species in three genera: Caenagnathus collinsi, Chirostenotes pergracilis and Leptorhynchos elegans gen. nov. Leptorhynchos is diagnosed by its small size, its short, deep mandible, and the upturned tip of the beak. A single caenagnathid is known from the late Campanian of Utah, Hagryphus giganteus. Two caenagnathid species occur in the Aguja Formation,?Chirostenotes sp. and Leptorhynchos gaddisi sp. nov. L. gaddisi differs from L. elegans in that the tip of the beak is narrower and less upturned. Phylogenetic analysis recovers Caenagnathidae and Oviraptoridae as monophyletic sister taxa. Within Caenagnathidae, the North American species seem to form a monophyletic assemblage, the Caenagnathinae, within which Chirostenotes and Caenagnathus form a clade to the exclusion of Leptorhynchos. The discovery of Chirostenotes gaddisi provides more evidence for the existence of a distinct dinosaurian fauna in southern North America during the Campanian. Furthermore, the Aguja fossils show that caenagnathids were widespread and highly diverse in the Late Cretaceous of North America. This diversity was maintained in two ways. First, variation in body size and beak shape suggests that diversity within formations is maintained by niche partitioning, in a way analogous to Darwin's finches. Second, diversity is maintained by high degree of endemism, with different species of caenagnathids occurring in different habitats.",
    url = "https://doi.org/10.3374/014.054.0102",
    doi = "10.3374/014.054.0102",
    openalex = "W2119575607",
    references = "doi1010160169534787900280, doi10103831635, doi101086273307, doi101098rspl18870117, doi1012067481, doi1016660022336020030770822mbatho20co2, doi1023074785, doi104095105003, doi105281zenodo16171435, doi107312kiel11918, gilmore1924a, openalexw3215057009"
}

ABSTRACTA new, exquisitely preserved specimen of a small mosasaur, referable to Mosasaurus missouriensis, is reported from the Bearpaw Formation (ca. 75 Ma, upper Campanian) of southern Alberta, Canada. Many calcified cartilaginous elements, including tracheal rings and the sternum, are preserved. The sternum most closely resembles that of Clidastes propython, bearing five shallow sternal rib facets on each side. Our comparative study of the new material with the holotype, referred material, and the genotype M. hoffmannii is congruent with the preexisting hypothesis that M. missouriensis and M. hoffmannii are phylogenetically more closely related to each other than to the other congeners, in spite of a temporal gap of nearly 10 million years between them. Also preserved with the mosasaur, inside its ribcage and around the specimen, are well-preserved aulopiform fish bones, including a skull. The fish skull is punctured and its centra truncated, suggesting macrophagy was employed by M. missouriensis despite the apparent lack of tooth wear. A sympatric specimen of Prognathodon overtoni is known to have consumed a sea turtle as well as fishes, and consistently exhibits apical wear across marginal teeth. We hypothesize that coexistence of these apex predators in the Bearpaw Sea was possible because of niche partitioning. Finally, the mosasaur carcass was likely scavenged by at least three lamniform sharks, based on their shed teeth and a series of truncated transverse processes on the mosasaur tail. ACKNOWLEDGMENTSThe authors thank the mining company, Korite International, for their initial discovery of the mosasaur specimen and promptly accommodating the field work by the Royal Tyrrell Museum to allow for its immediate collection. Additional field assistance was also provided by Korite International during the excavation, which was greatly appreciated. Study of TMP 2003.400.0001 was possible because of the recognition of its scientific importance by the Blood Tribe (Kainai), Chief, and Council, which provides the specimens on long-term loan to the Royal Tyrrell Museum. We are grateful for the assistance of R. Tailfeathers, who was instrumental in acquiring the specimen. We also thank M. Mitchell (TMP) for the careful and skillful preparation of TMP 2008.036.0001, including discovery and careful preparation of delicate calcified cartilaginous structures and of the fish material. A. Fotheringham (TMP) was responsible for the highly detailed preparation of all fish material, and B. Sanchez for the additional preparation of TMP 2003.400.0001. D. Sloan was instrumental in preparing the scientific illustrations for TMP 2008.036.0001 shown in Figures 2, 3, and 7. The careful and constructive comments provided by J. Lindgren, A. LeBlanc, and an anonymous reviewer improved the manuscript. T. Cook kindly provided comments on the shark portion of the manuscript, and H. Street generously provided T.K. with photographic images of KU 1034 and USNM 4910. Funding for this project was provided to T.K. by Government of Alberta Japanese-Canadian Initiative Postdoctoral Fellowship, to M.G.N. by Royal Tyrrell Museum Cooperating Society to support postdoctoral research as well as three travels in support of this research, and to M.W.C. by NSERC Discovery Grant no. 238458, NSERC Accelerator Grant, and Chairs Research Allowance.Handling editor: Jack Conrad

@article{doi101080027246342014838573,
    author = "Konishi, Takuya and Newbrey, Michael G. and Caldwell, Michael W.",
    title = "A small, exquisitely preserved specimen of Mosasaurus missouriensis (Squamata, Mosasauridae) from the upper Campanian of the Bearpaw Formation, western Canada, and the first stomach contents for the genus",
    year = "2014",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACTA new, exquisitely preserved specimen of a small mosasaur, referable to Mosasaurus missouriensis, is reported from the Bearpaw Formation (ca. 75 Ma, upper Campanian) of southern Alberta, Canada. Many calcified cartilaginous elements, including tracheal rings and the sternum, are preserved. The sternum most closely resembles that of Clidastes propython, bearing five shallow sternal rib facets on each side. Our comparative study of the new material with the holotype, referred material, and the genotype M. hoffmannii is congruent with the preexisting hypothesis that M. missouriensis and M. hoffmannii are phylogenetically more closely related to each other than to the other congeners, in spite of a temporal gap of nearly 10 million years between them. Also preserved with the mosasaur, inside its ribcage and around the specimen, are well-preserved aulopiform fish bones, including a skull. The fish skull is punctured and its centra truncated, suggesting macrophagy was employed by M. missouriensis despite the apparent lack of tooth wear. A sympatric specimen of Prognathodon overtoni is known to have consumed a sea turtle as well as fishes, and consistently exhibits apical wear across marginal teeth. We hypothesize that coexistence of these apex predators in the Bearpaw Sea was possible because of niche partitioning. Finally, the mosasaur carcass was likely scavenged by at least three lamniform sharks, based on their shed teeth and a series of truncated transverse processes on the mosasaur tail. ACKNOWLEDGMENTSThe authors thank the mining company, Korite International, for their initial discovery of the mosasaur specimen and promptly accommodating the field work by the Royal Tyrrell Museum to allow for its immediate collection. Additional field assistance was also provided by Korite International during the excavation, which was greatly appreciated. Study of TMP 2003.400.0001 was possible because of the recognition of its scientific importance by the Blood Tribe (Kainai), Chief, and Council, which provides the specimens on long-term loan to the Royal Tyrrell Museum. We are grateful for the assistance of R. Tailfeathers, who was instrumental in acquiring the specimen. We also thank M. Mitchell (TMP) for the careful and skillful preparation of TMP 2008.036.0001, including discovery and careful preparation of delicate calcified cartilaginous structures and of the fish material. A. Fotheringham (TMP) was responsible for the highly detailed preparation of all fish material, and B. Sanchez for the additional preparation of TMP 2003.400.0001. D. Sloan was instrumental in preparing the scientific illustrations for TMP 2008.036.0001 shown in Figures 2, 3, and 7. The careful and constructive comments provided by J. Lindgren, A. LeBlanc, and an anonymous reviewer improved the manuscript. T. Cook kindly provided comments on the shark portion of the manuscript, and H. Street generously provided T.K. with photographic images of KU 1034 and USNM 4910. Funding for this project was provided to T.K. by Government of Alberta Japanese-Canadian Initiative Postdoctoral Fellowship, to M.G.N. by Royal Tyrrell Museum Cooperating Society to support postdoctoral research as well as three travels in support of this research, and to M.W.C. by NSERC Discovery Grant no. 238458, NSERC Accelerator Grant, and Chairs Research Allowance.Handling editor: Jack Conrad",
    url = "https://doi.org/10.1080/02724634.2014.838573",
    doi = "10.1080/02724634.2014.838573",
    openalex = "W2120184736",
    references = "doi101080027246342011601714"
}

The Danek Bonebed (Horsethief Member, Horseshoe Canyon Formation, Late Campanian) is dominated by the remains of at least 12 Edmontosaurus regalis. Skeletal remains of a tyrannosaurid and ceratopsid are also known. The predominantly disarticulated remains were interred on a periodically inundated floodplain and, although the cause of death is unknown, a sudden, catastrophic death explains the demographic spread, faunal diversity, rare greenstick fractures, and homogeneous weathering/abrasion categories of the assemblage. The Danek Bonebed shares a similar taphonomic signature to the Liscomb Bonebed (Prince Creek Formation, Alaska), but it is unique among all other described hadrosaurid bonebeds in the unusually high proportion of bite-marked bones (∼30%), suggesting scavenging played a major role in the reworking of the assemblage. The highest frequency of bite marks is found on small, often unidentifiable (and commonly ignored) bone fragments, underscoring the role that such fragments can play in taphonomic interpretation. Finally, the recognition of E. regalis from central Alberta is an important datum linking contemporaneous occurrences in southern Alberta with slightly older records of this species from the Wapiti Formation in northwestern Alberta.

@article{doi101139cjes20140062,
    author = "Bell, Phil R. and Campione, Nicolás E.",
    title = "Taphonomy of the Danek Bonebed: a monodominant Edmontosaurus (Hadrosauridae) bonebed from the Horseshoe Canyon Formation, Alberta",
    year = "2014",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The Danek Bonebed (Horsethief Member, Horseshoe Canyon Formation, Late Campanian) is dominated by the remains of at least 12 Edmontosaurus regalis. Skeletal remains of a tyrannosaurid and ceratopsid are also known. The predominantly disarticulated remains were interred on a periodically inundated floodplain and, although the cause of death is unknown, a sudden, catastrophic death explains the demographic spread, faunal diversity, rare greenstick fractures, and homogeneous weathering/abrasion categories of the assemblage. The Danek Bonebed shares a similar taphonomic signature to the Liscomb Bonebed (Prince Creek Formation, Alaska), but it is unique among all other described hadrosaurid bonebeds in the unusually high proportion of bite-marked bones (∼30\%), suggesting scavenging played a major role in the reworking of the assemblage. The highest frequency of bite marks is found on small, often unidentifiable (and commonly ignored) bone fragments, underscoring the role that such fragments can play in taphonomic interpretation. Finally, the recognition of E. regalis from central Alberta is an important datum linking contemporaneous occurrences in southern Alberta with slightly older records of this species from the Wapiti Formation in northwestern Alberta.",
    url = "https://doi.org/10.1139/cjes-2014-0062",
    doi = "10.1139/cjes-2014-0062",
    openalex = "W2129084534",
    references = "doi101016jpalaeo200906004, doi101016jpalaeo201002029, doi101139cjes20120185, doi101139e05029, doi102110palo2009p09103r, doi107208chicago97802267237300010001"
}

The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.

@article{doi101371journalpone0092022,
    author = "Lamanna, Matthew C. and Sues, Hans‐Dieter and Schachner, Emma R. and Lyson, Tyler R.",
    title = "A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America",
    year = "2014",
    journal = "PLoS ONE",
    abstract = "The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.",
    url = "https://doi.org/10.1371/journal.pone.0092022",
    doi = "10.1371/journal.pone.0092022",
    openalex = "W2135294759",
    references = "doi10103831635, doi101038nature08322, doi101038nature10288, doi101111j10960031200800217x, doi101111j146979981985tb04915x, doi101126science2665186779, doi102475ajss31695411, doi102475ajss3179786, doi102475ajss319111253, doi104095105003, doi105860choice393984, doi105860choice435902"
}

Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian) of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis of dietary niche partitioning. The inferred mechanical and dietary patterns appear constant over the 1.5 Myr timespan of the Dinosaur Park Formation megaherbivore chronofauna, despite continual species turnover.

@article{doi101371journalpone0098605,
    author = "Mallon, Jordan C. and Anderson, Jason S.",
    title = "The Functional and Palaeoecological Implications of Tooth Morphology and Wear for the Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada",
    year = "2014",
    journal = "PLoS ONE",
    abstract = "Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian) of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis of dietary niche partitioning. The inferred mechanical and dietary patterns appear constant over the 1.5 Myr timespan of the Dinosaur Park Formation megaherbivore chronofauna, despite continual species turnover.",
    url = "https://doi.org/10.1371/journal.pone.0098605",
    doi = "10.1371/journal.pone.0098605",
    openalex = "W2033356851",
    references = "brinkman1990paleooecology, doi1010029780470750711, doi101002jmor10372, doi101016jpalaeo201206024, doi101017cbo9780511564345, doi101046j14429993200101070x, doi101080089129632012688589, doi101086653688, doi101093behecoarh107, doi101111j14429993200101070ppx, doi101139e78109, doi101186147267851314, doi101371journalpone0067182, doi1016690883135120010160482ttoaco20co2, doi101671027246342003231apfast20co2, doi1023072291098, doi105860choice326223, doi105962bhltitle115853, openalexw1540596182, openalexw2138825607, openalexw2183707334, openalexw575814759"
}

Three monodominant hadrosaurid bonebeds in the Horsethief Member of the Horseshoe Canyon Formation (uppermost Campanian) in southern Alberta, Canada, are documented. Each bonebed is hosted by a decimetre-thick deposit of poorly sorted and graded organic-fragment-rich mudstone. These fossil deposits are interpreted as having been carried and deposited by debris flows or hyperconcentrated mass sediment flows initiated by overbank flooding from local channels. Each bonebed is dominated (>50% of identifiable elements) by the disarticulated to occasionally associated remains of hadrosaurine hadrosaurids, inferred to be Edmontosaurus regalis. The majority of hadrosaurid elements at two of the sites (Bleriot Ferry and Prehistoric Park) are from large, presumably adult-sized individuals, whereas the majority of elements from the Fox Coulee site are from subadults and juveniles. Fossil elements from all the sites exhibit similar taphonomic signatures suggestive of a high degree of biostratinomic modification including: (i) thorough disarticulation of carcasses, (ii) a large amount of breakage, (iii) modest amounts of size sorting, and (iv) minimum to modest occurrences of abrasion, and scratch and tooth marks. These signatures indicate that carcasses were exposed for significant amounts of time on the floodplain, where they rotted, were scavenged and trampled, and were exposed to moving water prior to final burial. The size of each bonebed together with the density of bones suggest that the biocoenoses comprised large groups of hadrosaurids, and bone size distributions suggest the possibility of age-segregated populations. The monodominant nature of the assemblages combined with homogenous taphonomic signatures within and between sites suggests that these bonebed assemblages are best interpreted as the result of mass kills rather than attrition, with recurring tropical storm-induced coastal-plain flooding postulated as a likely mechanism for what killed and eventually buried these dinosaurs.

@article{doi101139cjes20140184,
    author = "Evans, David C. and Eberth, David A. and Ryan, Michael J.",
    title = "Hadrosaurid (Edmontosaurus) bonebeds from the Horseshoe Canyon Formation (Horsethief Member) at Drumheller, Alberta, Canada: geology, preliminary taphonomy, and significance",
    year = "2015",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Three monodominant hadrosaurid bonebeds in the Horsethief Member of the Horseshoe Canyon Formation (uppermost Campanian) in southern Alberta, Canada, are documented. Each bonebed is hosted by a decimetre-thick deposit of poorly sorted and graded organic-fragment-rich mudstone. These fossil deposits are interpreted as having been carried and deposited by debris flows or hyperconcentrated mass sediment flows initiated by overbank flooding from local channels. Each bonebed is dominated (>50\% of identifiable elements) by the disarticulated to occasionally associated remains of hadrosaurine hadrosaurids, inferred to be Edmontosaurus regalis. The majority of hadrosaurid elements at two of the sites (Bleriot Ferry and Prehistoric Park) are from large, presumably adult-sized individuals, whereas the majority of elements from the Fox Coulee site are from subadults and juveniles. Fossil elements from all the sites exhibit similar taphonomic signatures suggestive of a high degree of biostratinomic modification including: (i) thorough disarticulation of carcasses, (ii) a large amount of breakage, (iii) modest amounts of size sorting, and (iv) minimum to modest occurrences of abrasion, and scratch and tooth marks. These signatures indicate that carcasses were exposed for significant amounts of time on the floodplain, where they rotted, were scavenged and trampled, and were exposed to moving water prior to final burial. The size of each bonebed together with the density of bones suggest that the biocoenoses comprised large groups of hadrosaurids, and bone size distributions suggest the possibility of age-segregated populations. The monodominant nature of the assemblages combined with homogenous taphonomic signatures within and between sites suggests that these bonebed assemblages are best interpreted as the result of mass kills rather than attrition, with recurring tropical storm-induced coastal-plain flooding postulated as a likely mechanism for what killed and eventually buried these dinosaurs.",
    url = "https://doi.org/10.1139/cjes-2014-0184",
    doi = "10.1139/cjes-2014-0184",
    openalex = "W2165134975",
    references = "doi101016jpalaeo200906004, doi101139cjes20120185, doi102110palo2009p09103r, doi107208chicago97802267237300010001"
}

Upper Cretaceous dinosaur bonebeds are common in Alberta, Canada, and have attracted continuous scientific attention since the 1960s. Since its inception, the Royal Tyrrell Museum of Palaeontology has documented the presence of hundreds of these sites and has been involved directly in the scientific study of many tens. Because many of these bonebeds have been used to address questions about the paleobiology and paleoecology of dinosaurs, questions have arisen about bonebed origins and preservation in the Cretaceous of Alberta. This study of 260 bonebeds delineates broad paleoenvironmental settings and associations, and taphonomic signatures of assemblages as a first step in assessing patterns of dinosaur bonebed origins in the Upper Cretaceous of Alberta. Bonebeds are known predominantly from the Belly River Group and the Horseshoe Canyon, lower St. Mary River, Wapiti, and Scollard formations. In these units, bonebeds are mostly associated with river channel and alluvial wetland settings that were influenced by a subtropical to warm-temperate, monsoonal climate. Most bonebeds formed in response to flooding events capable of killing dinosaurs, reworking and modifying skeletal remains, and burying taphocoenoses. The “coastal-plain-flooding hypothesis,” proposed in 2005, suggested that many bonebeds in the Dinosaur Park Formation formed in response to the effects of recurring coastal-plain floods that submerged vast areas of ancient southern Alberta on a seasonal basis. It remains the best mechanism to explain how many of the bonebeds were formed and preserved at Dinosaur Provincial Park, and here, is proposed as the mechanism that best explains bonebed origins in other Upper Cretaceous formations across central and southern Alberta.

@article{doi101139cjes20140200,
    author = "Eberth, David A.",
    title = "Origins of dinosaur bonebeds in the Cretaceous of Alberta, Canada",
    year = "2015",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Upper Cretaceous dinosaur bonebeds are common in Alberta, Canada, and have attracted continuous scientific attention since the 1960s. Since its inception, the Royal Tyrrell Museum of Palaeontology has documented the presence of hundreds of these sites and has been involved directly in the scientific study of many tens. Because many of these bonebeds have been used to address questions about the paleobiology and paleoecology of dinosaurs, questions have arisen about bonebed origins and preservation in the Cretaceous of Alberta. This study of 260 bonebeds delineates broad paleoenvironmental settings and associations, and taphonomic signatures of assemblages as a first step in assessing patterns of dinosaur bonebed origins in the Upper Cretaceous of Alberta. Bonebeds are known predominantly from the Belly River Group and the Horseshoe Canyon, lower St. Mary River, Wapiti, and Scollard formations. In these units, bonebeds are mostly associated with river channel and alluvial wetland settings that were influenced by a subtropical to warm-temperate, monsoonal climate. Most bonebeds formed in response to flooding events capable of killing dinosaurs, reworking and modifying skeletal remains, and burying taphocoenoses. The “coastal-plain-flooding hypothesis,” proposed in 2005, suggested that many bonebeds in the Dinosaur Park Formation formed in response to the effects of recurring coastal-plain floods that submerged vast areas of ancient southern Alberta on a seasonal basis. It remains the best mechanism to explain how many of the bonebeds were formed and preserved at Dinosaur Provincial Park, and here, is proposed as the mechanism that best explains bonebed origins in other Upper Cretaceous formations across central and southern Alberta.",
    url = "https://doi.org/10.1139/cjes-2014-0200",
    doi = "10.1139/cjes-2014-0200",
    openalex = "W1805219736",
    references = "doi101016jpalaeo200902007, doi101016jpalaeo200906004, doi102110palo2014084, doi1035767gscpgbull444654, doi1035767gscpgbull452155"
}

The small triangular posteriorly oriented nasal crest of Probrachylophosaurus is proposed to represent a transitional nasal morphology between that of a non-crested ancestor such as Acristavus and the large flat posteriorly oriented nasal crest of adult Brachylophosaurus. Because Probrachylophosaurus is stratigraphically and morphologically intermediate between these taxa, Probrachylophosaurus is hypothesized to be an intermediate member of the Acristavus-Brachylophosaurus evolutionary lineage.

@article{doi101371journalpone0141304,
    author = "Fowler, Elizabeth A. Freedman and Horner, John R.",
    title = "A New Brachylophosaurin Hadrosaur (Dinosauria: Ornithischia) with an Intermediate Nasal Crest from the Campanian Judith River Formation of Northcentral Montana",
    year = "2015",
    journal = "PLoS ONE",
    abstract = "The small triangular posteriorly oriented nasal crest of Probrachylophosaurus is proposed to represent a transitional nasal morphology between that of a non-crested ancestor such as Acristavus and the large flat posteriorly oriented nasal crest of adult Brachylophosaurus. Because Probrachylophosaurus is stratigraphically and morphologically intermediate between these taxa, Probrachylophosaurus is hypothesized to be an intermediate member of the Acristavus-Brachylophosaurus evolutionary lineage.",
    url = "https://doi.org/10.1371/journal.pone.0141304",
    doi = "10.1371/journal.pone.0141304",
    openalex = "W2114007970",
    references = "doi101016jgca201006017, doi101016s0009254197001599, doi101016s0195667105800308, doi101017pab201519, doi101038282296a0, doi101038nature11264, doi101073pnas1313334111, doi101080027246342011557116, doi101098rspb20090229, doi101371journalpone0016574, doi101371journalpone0018029, doi101371journalpone0029958, doi1016710272463420000200115lbhoth20co2, doi10167102724634200727373aarolm20co2, doi105860choice435902, doi105860choice514447, doi105962bhltitle101747, doi105962bhltitle115853, horner2011dinosaur, köhler2012seasonal, openalexw2904473752, openalexw3217097258, vanitterbeeck2005stratigraphy"
}

Despite long-standing significance in the annals of North American stratigraphy and paleontology, key aspects of the Upper Cretaceous Judith River Formation remain poorly understood. We re-evaluate Judith River stratigraphy and propose new reference sections that both document the range of lithologies present in the type area in north-central Montana and reveal dramatic changes in facies architecture, fossil content, and rock accumulation rates that can be mapped throughout the type area and into the plains of southern Alberta and Saskatchewan. One section spans the basal contact of the Judith River Formation with marine shales of the underlying Claggett Formation. This contact, which lies along the base of the Parkman Sandstone Member of the Judith River Formation, is erosional and consistent with an episode of forced regression, contrary to previous descriptions. A second reference section spans the entire Judith River Formation. This complete section hosts a lithologic discontinuity, herein referred to as the mid-Judith discontinuity, that reflects a regional reorganization of terrestrial and marine depositional systems associated with a turnaround from regressive to transgressive deposition. The mid-Judith discontinuity correlates with the base of three backstepping marine sequences in the eastern sector of the type area and is thus interpreted as the terrestrial expression of a maximum regressive surface. This mid-Judith discontinuity defines the boundary between the new McClelland Ferry and overlying Coal Ridge Members of the Judith River Formation. The shallow marine sandstones that form the backstepping sequences represent the leading edge of the Bearpaw transgression in this region and are formalized as the new Woodhawk Member of the Judith River Formation in a third reference section. New 40Ar/39Ar ages indicate (1) that the mid-Judith discontinuity formed ∼76.2 Ma, coincident with the onset of the Bearpaw transgression in central Montana; and (2) that the Bearpaw Sea had advanced westward beyond the Judith River type area by ∼75.2 Ma, on the basis of the dating of a bentonite bed at the base of the Bearpaw Formation. These new ages also provide more confident age control for important vertebrate fossil occurrences in the Judith River Formation. Facies analysis across the mid-Judith discontinuity reveals how alluvial systems respond to regional base-level rise, which is implicit with the increase in rock accumulation rates and marine transgression. With the increase in accommodation signaled by the mid-Judith discontinuity, the alluvial system shifted in dominance from fluvial channel to overbank deposits, with greater tidal influence in channel sands, more hydromorphic and carbonaceous overbank deposits, and a higher frequency of bentonites and skeletal concentrations, suggesting higher preservation rates. These features, along with the appearance of extraformational pebbles above the discontinuity, are consistent with an upstream tectonic explanation for the addition of accommodation.

@article{doi101086684289,
    author = "Rogers, Raymond R. and Kidwell, Susan M. and Deino, Alan L. and Mitchell, James P. and Nelson, Kenneth and Thole, Jeffrey T.",
    title = "Age, Correlation, and Lithostratigraphic Revision of the Upper Cretaceous (Campanian) Judith River Formation in Its Type Area (North-Central Montana), with a Comparison of Low- and High-Accommodation Alluvial Records",
    year = "2016",
    journal = "The Journal of Geology",
    abstract = "Despite long-standing significance in the annals of North American stratigraphy and paleontology, key aspects of the Upper Cretaceous Judith River Formation remain poorly understood. We re-evaluate Judith River stratigraphy and propose new reference sections that both document the range of lithologies present in the type area in north-central Montana and reveal dramatic changes in facies architecture, fossil content, and rock accumulation rates that can be mapped throughout the type area and into the plains of southern Alberta and Saskatchewan. One section spans the basal contact of the Judith River Formation with marine shales of the underlying Claggett Formation. This contact, which lies along the base of the Parkman Sandstone Member of the Judith River Formation, is erosional and consistent with an episode of forced regression, contrary to previous descriptions. A second reference section spans the entire Judith River Formation. This complete section hosts a lithologic discontinuity, herein referred to as the mid-Judith discontinuity, that reflects a regional reorganization of terrestrial and marine depositional systems associated with a turnaround from regressive to transgressive deposition. The mid-Judith discontinuity correlates with the base of three backstepping marine sequences in the eastern sector of the type area and is thus interpreted as the terrestrial expression of a maximum regressive surface. This mid-Judith discontinuity defines the boundary between the new McClelland Ferry and overlying Coal Ridge Members of the Judith River Formation. The shallow marine sandstones that form the backstepping sequences represent the leading edge of the Bearpaw transgression in this region and are formalized as the new Woodhawk Member of the Judith River Formation in a third reference section. New 40Ar/39Ar ages indicate (1) that the mid-Judith discontinuity formed ∼76.2 Ma, coincident with the onset of the Bearpaw transgression in central Montana; and (2) that the Bearpaw Sea had advanced westward beyond the Judith River type area by ∼75.2 Ma, on the basis of the dating of a bentonite bed at the base of the Bearpaw Formation. These new ages also provide more confident age control for important vertebrate fossil occurrences in the Judith River Formation. Facies analysis across the mid-Judith discontinuity reveals how alluvial systems respond to regional base-level rise, which is implicit with the increase in rock accumulation rates and marine transgression. With the increase in accommodation signaled by the mid-Judith discontinuity, the alluvial system shifted in dominance from fluvial channel to overbank deposits, with greater tidal influence in channel sands, more hydromorphic and carbonaceous overbank deposits, and a higher frequency of bentonites and skeletal concentrations, suggesting higher preservation rates. These features, along with the appearance of extraformational pebbles above the discontinuity, are consistent with an upstream tectonic explanation for the addition of accommodation.",
    url = "https://doi.org/10.1086/684289",
    doi = "10.1086/684289",
    openalex = "W2274198338",
    references = "doi101006cres19941022, doi1010079783642859168, doi1010160031018288900855, doi101016003101829090202i, doi1010160037073891901395, doi101016003707389390022w, doi101016jgca2006061563, doi101016s0016703799002045, doi101016s0195667105800308, doi101111j136530911979tb00935x, doi101126science1154339, doi1011270078042120110011, doi101139cjes20120185, doi1016660094837336180, doi101666080251, doi1018814epiiugs2013v36i3002, doi1023071005355, eberth1990stratigraphy"
}

This study reports on a new ceratopsid, Spiclypeus shipporum gen et sp. nov., from the lower Coal Ridge Member of the Judith River Formation in Montana, USA, which dates to ~76 Ma (upper Campanian). The species is distinguished by rugose dorsal contacts on the premaxillae for the nasals, laterally projecting postorbital horncores, fully fused and anteriorly curled P1 and P2 epiparietals, and a posterodorsally projecting P3 epiparietal. The holotype specimen is also notable for its pathological left squamosal and humerus, which show varied signs of osteomyelitis and osteoarthritis. Although the postorbital horncores of Spiclypeus closely resemble those of the contemporaneous 'Ceratops', the horncores of both genera are nevertheless indistinguishable from those of some other horned dinosaurs, including Albertaceratops and Kosmoceratops; 'Ceratops' is therefore maintained as a nomen dubium. Cladistic analysis recovers Spiclypeus as the sister taxon to the clade Vagaceratops + Kosmoceratops, and appears transitional in the morphology of its epiparietals. The discovery of Spiclypeus adds to the poorly known dinosaur fauna of the Judith River Formation, and suggests faunal turnover within the formation.

@article{doi101371journalpone0154218,
    author = "Mallon, Jordan C. and Ott, Christopher J. and Larson, Peter L. and Iuliano, Edward M. and Evans, David C.",
    title = "Spiclypeus shipporum gen. et sp. nov., a Boldly Audacious New Chasmosaurine Ceratopsid (Dinosauria: Ornithischia) from the Judith River Formation (Upper Cretaceous: Campanian) of Montana, USA",
    year = "2016",
    journal = "PLoS ONE",
    abstract = "This study reports on a new ceratopsid, Spiclypeus shipporum gen et sp. nov., from the lower Coal Ridge Member of the Judith River Formation in Montana, USA, which dates to \textasciitilde 76 Ma (upper Campanian). The species is distinguished by rugose dorsal contacts on the premaxillae for the nasals, laterally projecting postorbital horncores, fully fused and anteriorly curled P1 and P2 epiparietals, and a posterodorsally projecting P3 epiparietal. The holotype specimen is also notable for its pathological left squamosal and humerus, which show varied signs of osteomyelitis and osteoarthritis. Although the postorbital horncores of Spiclypeus closely resemble those of the contemporaneous 'Ceratops', the horncores of both genera are nevertheless indistinguishable from those of some other horned dinosaurs, including Albertaceratops and Kosmoceratops; 'Ceratops' is therefore maintained as a nomen dubium. Cladistic analysis recovers Spiclypeus as the sister taxon to the clade Vagaceratops + Kosmoceratops, and appears transitional in the morphology of its epiparietals. The discovery of Spiclypeus adds to the poorly known dinosaur fauna of the Judith River Formation, and suggests faunal turnover within the formation.",
    url = "https://doi.org/10.1371/journal.pone.0154218",
    doi = "10.1371/journal.pone.0154218",
    openalex = "W2402671157",
    references = "doi101016jpalaeo200906004, doi101086684289, doi105281zenodo1048846"
}

Abstract Vertebrate microfossil bonebeds (VMBs)—localized concentrations of small resilient vertebrate hard parts—are commonly studied to recover otherwise rarely found small-bodied taxa, and to document relative taxonomic abundance and species richness in ancient vertebrate communities. Analyses of taphonomic comparability among VMBs have often found significant differences in size and shape distributions, and thus considered them to be non-isotaphonomic. Such outcomes of “strict” statistical tests of isotaphonomy suggest discouraging limits on the potential for broad, comparative paleoecological reconstruction using VMBs. Yet it is not surprising that sensitive statistical tests highlight variations among VMB sites, especially given the general lack of clarity with regard to the definition of “strict” isotaphonomic comparability. We rigorously sampled and compared six VMB localities representing two distinct paleoenvironments (channel and pond/lake) of the Upper Cretaceous Judith River Formation to evaluate biases related to sampling strategies and depositional context. Few defining distinctions in bioclast size and shape are evident in surface collections, and most site-to-site comparisons of sieved collections are indistinguishable (p ≤0.003). These results provide a strong case for taphonomic equivalence among the majority of Judith River VMBs, and bode well for future studies of paleoecology, particularly in relation to investigations of faunal membership and community structure in Late Cretaceous wetland ecosystems. The taphonomic comparability of pond/lake and channel-hosted VMBs in the Judith River Formation is also consistent with a formative model that contends that channel-hosted VMBs were reworked from pre-existing pond/lake assemblages, and thus share taphonomic history.

@article{doi101017pab201637,
    author = "Rogers, Raymond R. and Carrano, Matthew T. and Rogers, Kristina A. Curry and Perez, Magaly and Regan, Anik",
    title = "Isotaphonomy in concept and practice: an exploration of vertebrate microfossil bonebeds in the Upper Cretaceous (Campanian) Judith River Formation, north-central Montana",
    year = "2017",
    journal = "Paleobiology",
    abstract = "Abstract Vertebrate microfossil bonebeds (VMBs)—localized concentrations of small resilient vertebrate hard parts—are commonly studied to recover otherwise rarely found small-bodied taxa, and to document relative taxonomic abundance and species richness in ancient vertebrate communities. Analyses of taphonomic comparability among VMBs have often found significant differences in size and shape distributions, and thus considered them to be non-isotaphonomic. Such outcomes of “strict” statistical tests of isotaphonomy suggest discouraging limits on the potential for broad, comparative paleoecological reconstruction using VMBs. Yet it is not surprising that sensitive statistical tests highlight variations among VMB sites, especially given the general lack of clarity with regard to the definition of “strict” isotaphonomic comparability. We rigorously sampled and compared six VMB localities representing two distinct paleoenvironments (channel and pond/lake) of the Upper Cretaceous Judith River Formation to evaluate biases related to sampling strategies and depositional context. Few defining distinctions in bioclast size and shape are evident in surface collections, and most site-to-site comparisons of sieved collections are indistinguishable (p ≤0.003). These results provide a strong case for taphonomic equivalence among the majority of Judith River VMBs, and bode well for future studies of paleoecology, particularly in relation to investigations of faunal membership and community structure in Late Cretaceous wetland ecosystems. The taphonomic comparability of pond/lake and channel-hosted VMBs in the Judith River Formation is also consistent with a formative model that contends that channel-hosted VMBs were reworked from pre-existing pond/lake assemblages, and thus share taphonomic history.",
    url = "https://doi.org/10.1017/pab.2016.37",
    doi = "10.1017/pab.2016.37",
    openalex = "W2589812560",
    references = "carrano2016vertebrate, doi101006cres19941022, doi10100797814899503456, doi101016003101829190016k, doi101017s0094837300004929, doi101038142234b0, doi10108001621459196110482090, doi101086684289, doi101111j13652745200901566x, doi10166600948373200026103tap20co2, doi1023072800758, doi105281zenodo1048846, doi105860choice300309, openalexw2294506137, openalexw2474977981"
}

Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird Sapeornis both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in Limusaurus, a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation in ovo.

@article{doi101073pnas1708023114,
    author = "Wang, Shuo and Stiegler, Josef and Wu, Ping and Chuong, Cheng‐Ming and Hu, Dongyu and Balanoff, Amy M. and Zhou, Ya-Chun and Xu, Xing",
    title = "Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks",
    year = "2017",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird Sapeornis both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in Limusaurus, a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation in ovo.",
    url = "https://doi.org/10.1073/pnas.1708023114",
    doi = "10.1073/pnas.1708023114",
    openalex = "W2758615910",
    references = "doi101371journalpone0092022"
}

from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.

@article{doi101098rsos161086,
    author = "Arbour, Victoria M. and Evans, David C.",
    title = "A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation",
    year = "2017",
    journal = "Royal Society Open Science",
    abstract = "from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.",
    url = "https://doi.org/10.1098/rsos.161086",
    doi = "10.1098/rsos.161086",
    openalex = "W2613812864",
    references = "crossref1998encyclopedia, doi101007s125490110068y, doi101016jpalaeo200902007, doi101038378774a0, doi101086684289, doi101098rspl18870117, doi101111cla12160, doi101111j10960031200800217x, doi101111j10963642200900617x, doi101139e93016, doi101186s1289801601068, doi101371journalpone0108804, doi102110palo2014084, doi105860choice353642, doi105860choice393984, doi105860choice435902, openalexw3215057009"
}

A new troodontid dinosaur, Daliansaurus liaoningensis gen. et sp. nov., is erected based on a nearly complete specimen from the Lower Cretaceous Yixian Formation of Beipiao City, Liaoning Province, China. This well preserved skeleton provides important new details of the anatomy for Liaoning troodontids, and gives new insight into their phylogenetic relationships and evolution. Daliansaurus is distinguished from other troodontids by an enlarged ungual on pedal digit IV, which is approximately the same size as the sickle-shaped second ungual, and is differentiated from other Liaoning troodontids by a number of characters of the skull, manus, pelvis, and hindlimb. A phylogenetic analysis recovers Daliansaurus within a subclade of Liaoning troodontids that also includes Sinovenator, Sinusonasus, and Mei. We erect a name for this group—Sinovenatorinae—and argue that it reflects a localized radiation of small-bodied troodontids in the Early Cretaceous of eastern Asia, similar to previously recognized radiations of Liaoning dromaeosaurids and avialans. As more Liaoning theropods are discovered, it is becoming apparent that small, feathered paravians were particularly diverse during the Early Cretaceous, and future work is needed to clarify how this diversity arose, which species coexisted, and how these numerous species partitioned niches.

@article{doi1011111755672413307,
    author = "Shen, Caizhi and Lü, Junchang and Liu, Sizhao and Kundrát, Martin and Brusatte, Stephen L. and Gao, Hailong",
    title = "A New Troodontid Dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China",
    year = "2017",
    journal = "Acta Geologica Sinica - English Edition",
    abstract = "A new troodontid dinosaur, Daliansaurus liaoningensis gen. et sp. nov., is erected based on a nearly complete specimen from the Lower Cretaceous Yixian Formation of Beipiao City, Liaoning Province, China. This well preserved skeleton provides important new details of the anatomy for Liaoning troodontids, and gives new insight into their phylogenetic relationships and evolution. Daliansaurus is distinguished from other troodontids by an enlarged ungual on pedal digit IV, which is approximately the same size as the sickle-shaped second ungual, and is differentiated from other Liaoning troodontids by a number of characters of the skull, manus, pelvis, and hindlimb. A phylogenetic analysis recovers Daliansaurus within a subclade of Liaoning troodontids that also includes Sinovenator, Sinusonasus, and Mei. We erect a name for this group—Sinovenatorinae—and argue that it reflects a localized radiation of small-bodied troodontids in the Early Cretaceous of eastern Asia, similar to previously recognized radiations of Liaoning dromaeosaurids and avialans. As more Liaoning theropods are discovered, it is becoming apparent that small, feathered paravians were particularly diverse during the Early Cretaceous, and future work is needed to clarify how this diversity arose, which species coexisted, and how these numerous species partitioned niches.",
    url = "https://doi.org/10.1111/1755-6724.13307",
    doi = "10.1111/1755-6724.13307",
    openalex = "W2728300267",
    references = "openalexw2597671315"
}

Troodontids are known from Asia and North America, with the most complete specimens from the Jurassic of China and the Cretaceous of Mongolia. North American troodontids are poorly known, and specimens that have been described are isolated elements or partial skeletons with limited material. A new troodontid from the upper Dinosaur Park Formation (upper Campanian) is based on partial skulls, several vertebrae, ribs, gastralia, chevrons, a sacrum, partial pelvis, and partial fore and hind limbs. It is the largest troodontid known, with an estimated height of 180 cm and length of 350 cm. Like other troodontids, it possesses an elongated ambiens process and has a horizontal ventral margin of the postacetabular process. It differs from all other derived troodontids in that the slightly retroverted pubis has a shaft that curves anteroventrally. Some specimens from the Dinosaur Park Formation previously assigned to Troodon are reassigned to the new taxon, including multiple partial crania, an associated dentary and metatarsus, and a partial skeleton. Previously undescribed elements from the lower part of the Dinosaur Park Formation are assigned to the resurrected Stenonychosaurus inequalis. Distinct stratigraphic separation of Stenonychosaurus inequalis and the new taxon indicates a replacement in troodontid fauna, similar to the turnover of large ornithischians in the same formation. The new taxon is phylogenetically more closely related to Mongolian taxa, indicating the replacement of Stenonychosaurus may have been from an earlier Asian form immigrating into North America.

@article{doi101139cjes20170031,
    author = "van der Reest, Aaron J. and Currie, Philip J.",
    title = "Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: implications for deinonychosaur diversity in North America",
    year = "2017",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Troodontids are known from Asia and North America, with the most complete specimens from the Jurassic of China and the Cretaceous of Mongolia. North American troodontids are poorly known, and specimens that have been described are isolated elements or partial skeletons with limited material. A new troodontid from the upper Dinosaur Park Formation (upper Campanian) is based on partial skulls, several vertebrae, ribs, gastralia, chevrons, a sacrum, partial pelvis, and partial fore and hind limbs. It is the largest troodontid known, with an estimated height of 180 cm and length of 350 cm. Like other troodontids, it possesses an elongated ambiens process and has a horizontal ventral margin of the postacetabular process. It differs from all other derived troodontids in that the slightly retroverted pubis has a shaft that curves anteroventrally. Some specimens from the Dinosaur Park Formation previously assigned to Troodon are reassigned to the new taxon, including multiple partial crania, an associated dentary and metatarsus, and a partial skeleton. Previously undescribed elements from the lower part of the Dinosaur Park Formation are assigned to the resurrected Stenonychosaurus inequalis. Distinct stratigraphic separation of Stenonychosaurus inequalis and the new taxon indicates a replacement in troodontid fauna, similar to the turnover of large ornithischians in the same formation. The new taxon is phylogenetically more closely related to Mongolian taxa, indicating the replacement of Stenonychosaurus may have been from an earlier Asian form immigrating into North America.",
    url = "https://doi.org/10.1139/cjes-2017-0031",
    doi = "10.1139/cjes-2017-0031",
    openalex = "W2742325356",
    references = "doi101007s0011401411439, doi101007s1143400900096, doi101016jpalaeo201206024, doi101016jpalaeo201206027, doi101038415780a, doi101038nature02898, doi101038ncomms4289, doi101038ncomms4788, doi1010800272463420161269539, doi101139e93187, doi1012066481, doi1012067481, doi101371journalpone0024487, doi101371journalpone0054329, doi101371journalpone0093190, doi1016710272463420072787antdtf20co2, doi105860choice435902, doi105962p339375, openalexw2597671315"
}

Interbasinal stratigraphic correlation provides the foundation for all consequent continental-scale geological and paleontological analyses. Correlation requires synthesis of lithostratigraphic, biostratigraphic and geochronologic data, and must be periodically updated to accord with advances in dating techniques, changing standards for radiometric dates, new stratigraphic concepts, hypotheses, fossil specimens, and field data. Outdated or incorrect correlation exposes geological and paleontological analyses to potential error. The current work presents a high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. 40Ar / 39Ar radiometric dates are newly recalibrated to both current standard and decay constant pairings. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina formations, Texas, and recalibration corrections in particular affect the relative age positions of the Belly River Group, Alberta; Judith River Formation, Montana; Kaiparowits Formation, Utah; and Fruitland and Kirtland formations, New Mexico. The stratigraphic ranges of selected clades of dinosaur species are plotted on the chronostratigraphic framework, with some clades comprising short-duration species that do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern that is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. The recent hypothesis of intracontinental latitudinal provinciality of dinosaurs is shown to be affected by previous stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may be useful for high resolution biostratigraphy.

@article{doi101371journalpone0188426,
    author = "Fowler, Denver Warwick",
    title = "Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America.",
    year = "2017",
    journal = "PloS one",
    abstract = "Interbasinal stratigraphic correlation provides the foundation for all consequent continental-scale geological and paleontological analyses. Correlation requires synthesis of lithostratigraphic, biostratigraphic and geochronologic data, and must be periodically updated to accord with advances in dating techniques, changing standards for radiometric dates, new stratigraphic concepts, hypotheses, fossil specimens, and field data. Outdated or incorrect correlation exposes geological and paleontological analyses to potential error. The current work presents a high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. 40Ar / 39Ar radiometric dates are newly recalibrated to both current standard and decay constant pairings. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina formations, Texas, and recalibration corrections in particular affect the relative age positions of the Belly River Group, Alberta; Judith River Formation, Montana; Kaiparowits Formation, Utah; and Fruitland and Kirtland formations, New Mexico. The stratigraphic ranges of selected clades of dinosaur species are plotted on the chronostratigraphic framework, with some clades comprising short-duration species that do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern that is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. The recent hypothesis of intracontinental latitudinal provinciality of dinosaurs is shown to be affected by previous stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may be useful for high resolution biostratigraphy.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC5699823/",
    doi = "10.1371/journal.pone.0188426",
    openalex = "W2544476050",
    pmcid = "PMC5699823",
    pmid = "29166406",
    references = "doi1010160012821x77900607, doi101016016896228790025x, doi101016037594749090598g, doi101016jgca201006017, doi101016jgca201106021, doi101016jsedgeo200610001, doi101016s0009254197001599, doi101016s0016703799002045, doi101016s0375947497006131, doi101126science1154339, doi101130001676061952631011cotcfo20co2, doi101130b310761, doi101139e93016, doi101371journalpone0012292, doi101371journalpone0024487, doi101371journalpone0025186, doi101371journalpone0141304, doi10167102724634200727373aarolm20co2, doi105860choice514447, lehman1987late, openalexw2025327988"
}

The holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on the basis of fewer than 30 associated cranial and postcranial bones of a single individual from Dinosaur Provincial Park. Four additional partial skeletons of Saurornitholestes were recovered from Campanian (Upper Cretaceous) beds of Alberta and Montana over the next 25 years, although reasonably complete skeletons remained elusive, and virtually nothing was known about the skull. The lack of truly diagnostic material has been problematic, and the relationships of Saurornitholestes to other dromaeosaurids have been difficult to resolve because of the incomplete knowledge of its anatomy. In 2014, an almost complete skeleton, including the skull, was collected less than a kilometer from where the holotype had been found. Although similar in body size to Velociraptor, the facial region of the skull is relatively shorter, taller, and wider. The nasals are pneumatic. The premaxillary teeth are distinctive, and teeth previously identified in the Dinosaur Park Formation as Zapsalis abradens can now be identified as the second premaxillary tooth of S. langstoni. Morphology and wear patterns suggest that these may have been specialized for preening feathers. Many traits define a Campanian North American clade, Saurornitholestinae, that is distinct from an Asian clade that includes Velociraptor (Velociraptorinae). This new information on the skull allows a more complete evaluation of its systematic position within the Dromaeosauridae and supports the suggestion of at least two major faunal interchanges between Asia and North America during the Cretaceous. Anat Rec, 303:691-715, 2020. © 2019 American Association for Anatomy.

@article{doi101002ar24241,
    author = "Currie, Philip J. and Evans, David C.",
    title = "Cranial Anatomy of New Specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta",
    year = "2019",
    journal = "The Anatomical Record",
    abstract = "The holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on the basis of fewer than 30 associated cranial and postcranial bones of a single individual from Dinosaur Provincial Park. Four additional partial skeletons of Saurornitholestes were recovered from Campanian (Upper Cretaceous) beds of Alberta and Montana over the next 25 years, although reasonably complete skeletons remained elusive, and virtually nothing was known about the skull. The lack of truly diagnostic material has been problematic, and the relationships of Saurornitholestes to other dromaeosaurids have been difficult to resolve because of the incomplete knowledge of its anatomy. In 2014, an almost complete skeleton, including the skull, was collected less than a kilometer from where the holotype had been found. Although similar in body size to Velociraptor, the facial region of the skull is relatively shorter, taller, and wider. The nasals are pneumatic. The premaxillary teeth are distinctive, and teeth previously identified in the Dinosaur Park Formation as Zapsalis abradens can now be identified as the second premaxillary tooth of S. langstoni. Morphology and wear patterns suggest that these may have been specialized for preening feathers. Many traits define a Campanian North American clade, Saurornitholestinae, that is distinct from an Asian clade that includes Velociraptor (Velociraptorinae). This new information on the skull allows a more complete evaluation of its systematic position within the Dromaeosauridae and supports the suggestion of at least two major faunal interchanges between Asia and North America during the Cretaceous. Anat Rec, 303:691-715, 2020. © 2019 American Association for Anatomy.",
    url = "https://doi.org/10.1002/ar.24241",
    doi = "10.1002/ar.24241",
    openalex = "W2972619786",
    references = "doi101016jcub201408034, doi101017cbo9780511608377011, doi10103831635, doi101038nature13467, doi101080027246342015982797, doi101086684289, doi101098rspl18870117, doi101111cla12160, doi1012067481, doi101671027246342003231apfast20co2, doi1021741874453201003010041, doi107717peerj1032, sues1977dentaries"
}

Modern megaherbivore community richness is limited by bottom-up controls, such as resource limitation and resultant dietary competition. However, the extent to which these same controls impacted the richness of fossil megaherbivore communities is poorly understood. The present study investigates the matter with reference to the megaherbivorous dinosaur assemblage from the middle to upper Campanian Dinosaur Park Formation of Alberta, Canada. Using a meta-analysis of 21 ecomorphological variables measured across 14 genera, contemporaneous taxa are demonstrably well-separated in ecomorphospace at the family/subfamily level. Moreover, this pattern is persistent through the approximately 1.5 Myr timespan of the formation, despite continual species turnover, indicative of underlying structural principles imposed by long-term ecological competition. After considering the implications of ecomorphology for megaherbivorous dinosaur diet, it is concluded that competition structured comparable megaherbivorous dinosaur communities throughout the Late Cretaceous of western North America.

@article{doi101038s41598019517095,
    author = "Mallon, Jordan C.",
    title = "Competition structured a Late Cretaceous megaherbivorous dinosaur assemblage",
    year = "2019",
    journal = "Scientific Reports",
    abstract = "Modern megaherbivore community richness is limited by bottom-up controls, such as resource limitation and resultant dietary competition. However, the extent to which these same controls impacted the richness of fossil megaherbivore communities is poorly understood. The present study investigates the matter with reference to the megaherbivorous dinosaur assemblage from the middle to upper Campanian Dinosaur Park Formation of Alberta, Canada. Using a meta-analysis of 21 ecomorphological variables measured across 14 genera, contemporaneous taxa are demonstrably well-separated in ecomorphospace at the family/subfamily level. Moreover, this pattern is persistent through the approximately 1.5 Myr timespan of the formation, despite continual species turnover, indicative of underlying structural principles imposed by long-term ecological competition. After considering the implications of ecomorphology for megaherbivorous dinosaur diet, it is concluded that competition structured comparable megaherbivorous dinosaur communities throughout the Late Cretaceous of western North America.",
    url = "https://doi.org/10.1038/s41598-019-51709-5",
    doi = "10.1038/s41598-019-51709-5",
    openalex = "W2981425882",
    references = "doi101007978146124018114, doi101017cbo9780511565441, doi101017cbo9780511608551, doi101017cbo9780511735011, doi101086653688, doi101093biomet301281, doi101098rsos161086, doi101111j15023931200900187x, doi101139cjes20120185, doi101139e10005, doi101139e78109, doi101186147267851314, doi1012060003008220023660001aitrou20co2, doi101371journalpone0098605, doi101371journalpone0175253, doi101371journalpone0188426, doi1023073545850, doi1023075663, doi102475ajs2628975, openalexw2183707334"
}

The first fossil remains of vertebrates, invertebrates, plants and palynomorphs of the Chorrillo Formation (Austral Basin), about 30km to the SW of the town of El Calafate (Province of Santa Cruz), are described. Fossils include the elasmarian (basal Iguanodontia) Isasicursor santacrucensis gen. et sp. nov., the large titanosaur Nullotitan glaciaris gen. et sp. nov., both large and small Megaraptoridae indet., and fragments of sauropod and theropod eggshells. The list of vertebrates is also composed by the Neognathae Kookne yeutensis gen. et sp. nov., two isolated caudal vertebrae of Mammalia indet., and isolated teeth of a large mosasaur. Remains of fishes, anurans, turtles, and snakes are represented by fragmentary material of low taxonomical value, with the exception of remains belonging to Calyptocephalellidae. On the other hand, a remarkable diversity of terrestrial and freshwater gastropods has been documented, as well as fossil woods and palinological assemblages. The Chorrillo Formation continues south, in the Las Chinas River valley, southern Chile, where it is called Dorotea Formation. Both units share in their lower two thirds abundant materials of titanosaurs, whose remains cease to appear in the upper third, registering only elasmarians (Chorrillo Formation) and hadrosaurs (Dorotea Formation). Above both units there are levels with remains of invertebrates and marine reptiles. It is striking that the dinosaurs of the lower two thirds of the Chorrillo and Dorotea formations are represented by large basal titanosaurs and Megaraptoridae coelurosaurs, being the Saltasaurinae and Aeolosaurinae sauropods and Abelisauridae theropods totally absent. In contrast, these taxa are dominant components in sedimentary units of central and northern Patagonia (e.g., Allen, Los Alamitos, La Colonia formations). Such differences could reflect, in part, a greater antiquity (i.e., late Campanian-early Maastrichtian) for the Chorrillo fossils, or, more probably, different environmental conditions. Thus, knowledge of the biota of the southern tip of Patagonia is expanded, particularly those temporarily close to the K-Pg boundary.

@article{doi1022179revmacn21655,
    author = "Novas, Fernando E. and Agnolín, Federico L. and Rozadilla, Sebastián and Aranciaga-Rolando, Alexis Mauro and Brissón-Eli, Federico and Motta, Matías J. and Cerroni, Mauricio A. and Ezcurra, Martín D. and Martinelli, Agustín G. and ́Angelo, Julia D and Álvarez-Herrera, Gerardo P. and Gentil, Adriel R. and Bogan, Sergio and Chimento, Nicolás R. and Garcia-Marsà, Jordi A. and Coco, Gastón Lo and Miquel, Sergio E. and Brito, Fátima and Vera, Ezequiel I. and Loinaze, Valeria S. Pérez and Fernández, Mariela Soledad and Salgado, Leonardo",
    title = "Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina",
    year = "2019",
    journal = "Revista del Museo Argentino de Ciencias Naturales",
    abstract = "The first fossil remains of vertebrates, invertebrates, plants and palynomorphs of the Chorrillo Formation (Austral Basin), about 30km to the SW of the town of El Calafate (Province of Santa Cruz), are described. Fossils include the elasmarian (basal Iguanodontia) Isasicursor santacrucensis gen. et sp. nov., the large titanosaur Nullotitan glaciaris gen. et sp. nov., both large and small Megaraptoridae indet., and fragments of sauropod and theropod eggshells. The list of vertebrates is also composed by the Neognathae Kookne yeutensis gen. et sp. nov., two isolated caudal vertebrae of Mammalia indet., and isolated teeth of a large mosasaur. Remains of fishes, anurans, turtles, and snakes are represented by fragmentary material of low taxonomical value, with the exception of remains belonging to Calyptocephalellidae. On the other hand, a remarkable diversity of terrestrial and freshwater gastropods has been documented, as well as fossil woods and palinological assemblages. The Chorrillo Formation continues south, in the Las Chinas River valley, southern Chile, where it is called Dorotea Formation. Both units share in their lower two thirds abundant materials of titanosaurs, whose remains cease to appear in the upper third, registering only elasmarians (Chorrillo Formation) and hadrosaurs (Dorotea Formation). Above both units there are levels with remains of invertebrates and marine reptiles. It is striking that the dinosaurs of the lower two thirds of the Chorrillo and Dorotea formations are represented by large basal titanosaurs and Megaraptoridae coelurosaurs, being the Saltasaurinae and Aeolosaurinae sauropods and Abelisauridae theropods totally absent. In contrast, these taxa are dominant components in sedimentary units of central and northern Patagonia (e.g., Allen, Los Alamitos, La Colonia formations). Such differences could reflect, in part, a greater antiquity (i.e., late Campanian-early Maastrichtian) for the Chorrillo fossils, or, more probably, different environmental conditions. Thus, knowledge of the biota of the southern tip of Patagonia is expanded, particularly those temporarily close to the K-Pg boundary.",
    url = "https://doi.org/10.22179/revmacn.21.655",
    doi = "10.22179/revmacn.21.655",
    openalex = "W2993538476",
    references = "doi101016jcretres200806007, doi101016jrevpalbo200709004, doi101038s41598019453069, doi101038srep06196, doi101093zoolinneanzlx103, doi101098rspb20171219, doi101371journalpone0044318"
}

embryos are remarkably rare. Here we report an exceptionally preserved, articulated oviraptorid embryo inside an elongatoolithid egg, from the Late Cretaceous Hekou Formation of southern China. The head lies ventral to the body, with the feet on either side, and the back curled along the blunt pole of the egg, in a posture previously unrecognized in a non-avian dinosaur, but reminiscent of a late-stage modern bird embryo. Comparison to other late-stage oviraptorid embryos suggests that prehatch oviraptorids developed avian-like postures late in incubation, which in modern birds are related to coordinated embryonic movements associated with tucking - a behavior controlled by the central nervous system, critical for hatching success. We propose that such pre-hatching behavior, previously considered unique to birds, may have originated among non-avian theropods, which can be further investigated with additional discoveries of embryo fossils.

@article{doi101016jisci2021103516,
    author = "Xing, Lida and Niu, Kecheng and Ma, Waisum and Zelenitsky, Darla K. and Yang, Tzu-Ruei and Brusatte, Stephen L.",
    title = "An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures",
    year = "2021",
    journal = "iScience",
    abstract = "embryos are remarkably rare. Here we report an exceptionally preserved, articulated oviraptorid embryo inside an elongatoolithid egg, from the Late Cretaceous Hekou Formation of southern China. The head lies ventral to the body, with the feet on either side, and the back curled along the blunt pole of the egg, in a posture previously unrecognized in a non-avian dinosaur, but reminiscent of a late-stage modern bird embryo. Comparison to other late-stage oviraptorid embryos suggests that prehatch oviraptorids developed avian-like postures late in incubation, which in modern birds are related to coordinated embryonic movements associated with tucking - a behavior controlled by the central nervous system, critical for hatching success. We propose that such pre-hatching behavior, previously considered unique to birds, may have originated among non-avian theropods, which can be further investigated with additional discoveries of embryo fossils.",
    url = "https://doi.org/10.1016/j.isci.2021.103516",
    doi = "10.1016/j.isci.2021.103516",
    openalex = "W4200185644",
    references = "doi101038ncomms4788, doi1012060003009044011, doi101642auk152161, doi1033740140540102, lee2019a"
}

The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elements. Here we reassess DPF theropod biodiversity using morphological comparisons, high-resolution biostratigraphy, and morphometric analyses, with a focus on specimens/taxa originally described from isolated material. In addition to clarifying taxic diversity, we test whether DPF theropods preserve faunal zonation/turnover patterns similar to those previously documented for megaherbivores. Frontal bones referred to a therizinosaur (cf. Erlikosaurus), representing among the only skeletal record of the group from the Campanian–Maastrichtian (83–66 Ma) fossil record of North America, plot most closely to troodontids in morphospace, distinct from non-DPF therizinosaurs, a placement supported by a suite of troodontid anatomical frontal characters. Postcranial material referred to cf. Erlikosaurus in North America is also reviewed and found most similar in morphology to caenagnathids, rather than therizinosaurs. Among troodontids, we document considerable morphospace and biostratigraphic overlap between Stenonychosaurus and the recently described Latenivenatrix, as well as a variable distribution of putatively autapomorphic characters, calling the validity of the latter taxon into question. Biostratigraphically, there are no broad-scale patterns of faunal zonation similar to those previously documented in ornithischians from the DPF, with many theropods ranging throughout much of the formation and overlapping extensively, possibly reflecting a lack of sensitivity to environmental changes, or other cryptic ecological or evolutionary factors.

@article{doi101139cjes20200145,
    author = "Cullen, Thomas M. and Zanno, Lindsay E. and Larson, Derek W. and Todd, Erinn and Currie, Philip J. and Evans, David C.",
    title = "Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation 1",
    year = "2021",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elements. Here we reassess DPF theropod biodiversity using morphological comparisons, high-resolution biostratigraphy, and morphometric analyses, with a focus on specimens/taxa originally described from isolated material. In addition to clarifying taxic diversity, we test whether DPF theropods preserve faunal zonation/turnover patterns similar to those previously documented for megaherbivores. Frontal bones referred to a therizinosaur (cf. Erlikosaurus), representing among the only skeletal record of the group from the Campanian–Maastrichtian (83–66 Ma) fossil record of North America, plot most closely to troodontids in morphospace, distinct from non-DPF therizinosaurs, a placement supported by a suite of troodontid anatomical frontal characters. Postcranial material referred to cf. Erlikosaurus in North America is also reviewed and found most similar in morphology to caenagnathids, rather than therizinosaurs. Among troodontids, we document considerable morphospace and biostratigraphic overlap between Stenonychosaurus and the recently described Latenivenatrix, as well as a variable distribution of putatively autapomorphic characters, calling the validity of the latter taxon into question. Biostratigraphically, there are no broad-scale patterns of faunal zonation similar to those previously documented in ornithischians from the DPF, with many theropods ranging throughout much of the formation and overlapping extensively, possibly reflecting a lack of sensitivity to environmental changes, or other cryptic ecological or evolutionary factors.",
    url = "https://doi.org/10.1139/cjes-2020-0145",
    doi = "10.1139/cjes-2020-0145",
    openalex = "W3183001791",
    references = "béland1979ectothermy, crossref1998encyclopedia, doi101002ar24241, doi1010079780387981413, doi10100797833192427749, doi101016jcub201803042, doi101016jpalaeo201206027, doi1011112041210x12035, doi101111j2041210x201100153x, doi101130g473991, doi101139cjes20170034, doi101139e09050, doi101139e72031, doi101139e93016, doi101186s1289801601068, doi1018435vamp29362, doi1023072669711, doi105860choice353642, doi105860choice435902, openalexw2561546966"
}

The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America's Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the 'zenith of dinosaur diversity'. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U-Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 ± 0.074 Ma to 73.496 ± 0.039 Ma (2σ internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.

@article{doi101038s4159802219896w,
    author = "Ramezani, Jahandar and Beveridge, Tegan L and Rogers, Raymond R and Eberth, David A and Roberts, Eric M",
    title = "Calibrating the zenith of dinosaur diversity in the Campanian of the Western Interior Basin by CA-ID-TIMS U-Pb geochronology.",
    year = "2022",
    journal = "Scientific reports",
    abstract = "The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America's Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the 'zenith of dinosaur diversity'. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U-Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 ± 0.074 Ma to 73.496 ± 0.039 Ma (2σ internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC9512893/",
    doi = "10.1038/s41598-022-19896-w",
    pmcid = "PMC9512893",
    pmid = "36163377"
}

Terrestrial strata of the Judith River−Belly River wedge, widely exposed in the plains of north-central Montana, southern Alberta, and southwestern Saskatchewan, were pivotal in early stratigraphic investigations of the Western Interior of North America and are renowned to this day for their spectacular preservation of Late Cretaceous fossils, most notably dinosaurs. Correlation of the Judith River Formation in Montana with the Foremost, Oldman, and Dinosaur Park Formations (= Belly River Group) in Canada has been challenging for a variety of reasons, including lithostratigraphic complexities, legacy bentonite ages of limited comparability, and distinctly different stratigraphic models on opposite sides of the international border. An updated model calibrated with U-Pb zircon ages provides an improved framework for stratigraphic analysis. New geochronology indicates that the Oldman−Dinosaur Park discontinuity in Dinosaur Provincial Park correlates in age with the mid-Judith discontinuity in the Judith River Formation in Montana, which is interpreted as an expansion surface linked to a major pulse of accommodation and onset of the Bearpaw transgression at ca. 76.3 Ma. The regionally expressed shift in alluvial facies marking the mid-Judith discontinuity can be traced in well logs from Montana to southern Canada, where it loses distinction and transitions to a subsurface signature typical of the Oldman−Dinosaur Park discontinuity, which in turn can be traced north to Dinosaur Provincial Park and beyond. Across this expanse, both discontinuities parallel the Eagle/Milk River shoulder at approximately the same stratigraphic height, confirming their chronostratigraphic significance. These findings have clear implications for regional correlation and the evolution of alluvial depositional systems in a foreland basin setting, and they afford an opportunity to evaluate existing interpretations and advance understanding of the stratigraphy and paleontology of the Judith River−Belly River wedge. The term “Judith River−Belly River discontinuity” should be used henceforth to refer to the chronostratigraphically significant stratal discontinuity that subdivides the Judith River−Belly River wedge throughout the plains of north-central Montana, southern Alberta, and southwestern Saskatchewan.

@article{doi101130b369991,
    author = "Rogers, R. and Eberth, D. and Ramezani, J.",
    title = "The “Judith River−Belly River problem” revisited (Montana-Alberta-Saskatchewan): New perspectives on the correlation of Campanian dinosaur-bearing strata based on a revised stratigraphic model updated with CA-ID-TIMS U-Pb geochronology",
    year = "2023",
    journal = "Geological Society of America Bulletin",
    abstract = "Terrestrial strata of the Judith River−Belly River wedge, widely exposed in the plains of north-central Montana, southern Alberta, and southwestern Saskatchewan, were pivotal in early stratigraphic investigations of the Western Interior of North America and are renowned to this day for their spectacular preservation of Late Cretaceous fossils, most notably dinosaurs. Correlation of the Judith River Formation in Montana with the Foremost, Oldman, and Dinosaur Park Formations (= Belly River Group) in Canada has been challenging for a variety of reasons, including lithostratigraphic complexities, legacy bentonite ages of limited comparability, and distinctly different stratigraphic models on opposite sides of the international border. An updated model calibrated with U-Pb zircon ages provides an improved framework for stratigraphic analysis. New geochronology indicates that the Oldman−Dinosaur Park discontinuity in Dinosaur Provincial Park correlates in age with the mid-Judith discontinuity in the Judith River Formation in Montana, which is interpreted as an expansion surface linked to a major pulse of accommodation and onset of the Bearpaw transgression at ca. 76.3 Ma. The regionally expressed shift in alluvial facies marking the mid-Judith discontinuity can be traced in well logs from Montana to southern Canada, where it loses distinction and transitions to a subsurface signature typical of the Oldman−Dinosaur Park discontinuity, which in turn can be traced north to Dinosaur Provincial Park and beyond. Across this expanse, both discontinuities parallel the Eagle/Milk River shoulder at approximately the same stratigraphic height, confirming their chronostratigraphic significance. These findings have clear implications for regional correlation and the evolution of alluvial depositional systems in a foreland basin setting, and they afford an opportunity to evaluate existing interpretations and advance understanding of the stratigraphy and paleontology of the Judith River−Belly River wedge. The term “Judith River−Belly River discontinuity” should be used henceforth to refer to the chronostratigraphically significant stratal discontinuity that subdivides the Judith River−Belly River wedge throughout the plains of north-central Montana, southern Alberta, and southwestern Saskatchewan.",
    url = "https://www.semanticscholar.org/paper/22fd68c0d2a4cf7272f986cdeb949ee205bef9b8",
    doi = "10.1130/b36999.1",
    is_oa = "true",
    semanticscholar_citation_count = "11",
    semanticscholar_id = "22fd68c0d2a4cf7272f986cdeb949ee205bef9b8"
}

Reported lizard material from the Wapiti Formation (central-western Alberta, Canada) is limited to fragmentary remains of Kleskunsaurus grandeprairiensis and Socognathus unicuspis, a partial dentary attributed to Chamops cf. C. segnis, and a vertebra reportedly comparable to those of the much larger lizard Palaeosaniwa canadensis. P. canadensis is a Late Cretaceous North American member of Monstersauria, a Mesozoic and Cenozoic anguimorph group represented today by five species of Heloderma. Here, we document new squamate material from the DC Bonebed locality (Wapiti Unit 3; Campanian), including a right frontal identified as cf. P. canadensis and a taxonomically indeterminate squamate astragalocalcaneum. A partial skeleton from the Two Medicine Formation of Montana provisionally attributed to P. canadensis has a frontal resembling the corresponding element from the DC Bonebed in overall shape, in having narrowly separated facets for the prefrontal and postorbitofrontal, and in bearing osteoderms similar to the DC specimen’s in ornamentation and configuration. The Two Medicine and DC specimens differ from a roughly contemporaneous frontal from southern Alberta referred to the monstersaur Labrodioctes montanensis. The DC specimen confirms the presence of monstersaurian squamates in the Wapiti Formation, representing the northernmost record of any definitive Late Cretaceous monstersaur to date.

@article{doi103390geosciences13110337,
    author = "Hamilton, Samantha M. and Paparella, Ilaria and Bell, Phil R. and Campione, Nicolás E. and Fanti, Federico and Larson, Derek W. and Sissons, Robin L. and Vavrek, Matthew J. and Balsai, Michael J. and Sullivan, Corwin",
    title = "New Lizard Specimens from the Campanian Wapiti Formation of Alberta, Canada",
    year = "2023",
    journal = "Geosciences",
    abstract = "Reported lizard material from the Wapiti Formation (central-western Alberta, Canada) is limited to fragmentary remains of Kleskunsaurus grandeprairiensis and Socognathus unicuspis, a partial dentary attributed to Chamops cf. C. segnis, and a vertebra reportedly comparable to those of the much larger lizard Palaeosaniwa canadensis. P. canadensis is a Late Cretaceous North American member of Monstersauria, a Mesozoic and Cenozoic anguimorph group represented today by five species of Heloderma. Here, we document new squamate material from the DC Bonebed locality (Wapiti Unit 3; Campanian), including a right frontal identified as cf. P. canadensis and a taxonomically indeterminate squamate astragalocalcaneum. A partial skeleton from the Two Medicine Formation of Montana provisionally attributed to P. canadensis has a frontal resembling the corresponding element from the DC Bonebed in overall shape, in having narrowly separated facets for the prefrontal and postorbitofrontal, and in bearing osteoderms similar to the DC specimen’s in ornamentation and configuration. The Two Medicine and DC specimens differ from a roughly contemporaneous frontal from southern Alberta referred to the monstersaur Labrodioctes montanensis. The DC specimen confirms the presence of monstersaurian squamates in the Wapiti Formation, representing the northernmost record of any definitive Late Cretaceous monstersaur to date.",
    url = "https://doi.org/10.3390/geosciences13110337",
    doi = "10.3390/geosciences13110337",
    openalex = "W4388304841",
    references = "doi104095105060"
}

, was part of a clade restricted to a small portion of northern Laramidia approximately 78 million years ago. This group, Albertaceratopsini, was one of multiple centrosaurine clades to undergo geographically restricted radiations, with Nasutuceratopsini restricted to the south and Centrosaurini and Pachyrostra restricted to the north. High regional endemism in centrosaurs is associated with, and may have been driven by, high speciation rates and diversity, with competition between dinosaurs limiting their geographic range. High speciation rates may in turn have been driven in part by sexual selection or latitudinally uneven climatic and floral gradients. The high endemism seen in centrosaurines and other dinosaurs implies that dinosaur diversity is underestimated and contrasts with the large geographic ranges seen in most extant mammalian megafauna.

@article{doi107717peerj17224,
    author = "Loewen, Mark A. and Sertich, Joseph J. W. and Sampson, Scott D. and O’Connor, Jingmai K. and Carpenter, Savhannah and Sisson, Brock and Øhlenschlæger, Anna and Farke, Andrew A. and Makovicky, Peter J. and Longrich, Nick and Evans, David C.",
    title = "Lokiceratops rangiformis gen. et sp. nov. (Ceratopsidae: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals rapid regional radiations and extreme endemism within centrosaurine dinosaurs",
    year = "2024",
    journal = "PeerJ",
    abstract = ", was part of a clade restricted to a small portion of northern Laramidia approximately 78 million years ago. This group, Albertaceratopsini, was one of multiple centrosaurine clades to undergo geographically restricted radiations, with Nasutuceratopsini restricted to the south and Centrosaurini and Pachyrostra restricted to the north. High regional endemism in centrosaurs is associated with, and may have been driven by, high speciation rates and diversity, with competition between dinosaurs limiting their geographic range. High speciation rates may in turn have been driven in part by sexual selection or latitudinally uneven climatic and floral gradients. The high endemism seen in centrosaurines and other dinosaurs implies that dinosaur diversity is underestimated and contrasts with the large geographic ranges seen in most extant mammalian megafauna.",
    url = "https://doi.org/10.7717/peerj.17224",
    doi = "10.7717/peerj.17224",
    openalex = "W4399859744",
    references = "doi101007s1254202100555w, doi101016jcretres2019104308, doi101016jgca201006017, doi101016jpalaeo201512015, doi101111cla12160, doi101111j10960031200800217x, doi101126science1154339, doi101126science23547931156, doi101146annurevecolsys271597, doi101146annureven10010165000525, doi101371journalpone0292318, doi10230730135049, doi102475ajs3042105, doi107717peerj4265, openalexw3215057009"
}

The badlands of Dinosaur Provincial Park (Alberta, Canada) are renowned for the exceptional abundance and diversity of Campanian-aged vertebrate body fossils, especially dinosaurs. Due to the steep exposures and rapid erosion, dinosaur tracks and trackways are considered extremely rare but have been recorded from a small number of concretionary casts, which pertain to hadrosaurids and a single tyrannosaurid. Here, we document the first multitaxic dinosaur footprint assemblage from the Dinosaur Park Formation based on a new locality that contains multiple individual ceratopsids, two tyrannosaurids, a possible ankylosaurian, and a small theropod-like taxon. Ceratopsid tracks are globally rare but dominate the new tracksite, suggesting gregarious behaviour, which is also supported by their regular spacing and parallel arrangement. The possible ankylosaurian track is identified (in part) on account of having three distinct pedal digits, consistent with the pedal anatomy of several Dinosaur Park ankylosaurids (Euoplocephalus, Dyoplosaurus) and the newly erected ichnotaxon Ruopodosaurus clava but differentiating it from other ankylosaurian tracks (Tetrapodosaurus isp.). Importantly, the new tracks are the first natural moulds (concave epirelief) found in Dinosaur Provincial Park, which, due to the unique geomorphology of the area, can only be recognised in outcrops where there are prominent sediment displacement rims. The new search image outlined here has already resulted in several subsequent trackway discoveries, and has the potential to transform ichnological studies in the Dinosaur Park Formation and related formations where badlands prevail.

@article{bell2025a,
    author = "Bell, Phil R. and Pickles, Brian J. and Ashby, Sarah C. and Walker, Issy E. and Hurst, Sally and Rampe, Michael and Durkin, Paul and Brown, Caleb M.",
    title = "A ceratopsid-dominated tracksite from the Dinosaur Park Formation (Campanian) at Dinosaur Provincial Park, Alberta, Canada",
    year = "2025",
    journal = "PLOS One",
    abstract = "The badlands of Dinosaur Provincial Park (Alberta, Canada) are renowned for the exceptional abundance and diversity of Campanian-aged vertebrate body fossils, especially dinosaurs. Due to the steep exposures and rapid erosion, dinosaur tracks and trackways are considered extremely rare but have been recorded from a small number of concretionary casts, which pertain to hadrosaurids and a single tyrannosaurid. Here, we document the first multitaxic dinosaur footprint assemblage from the Dinosaur Park Formation based on a new locality that contains multiple individual ceratopsids, two tyrannosaurids, a possible ankylosaurian, and a small theropod-like taxon. Ceratopsid tracks are globally rare but dominate the new tracksite, suggesting gregarious behaviour, which is also supported by their regular spacing and parallel arrangement. The possible ankylosaurian track is identified (in part) on account of having three distinct pedal digits, consistent with the pedal anatomy of several Dinosaur Park ankylosaurids (Euoplocephalus, Dyoplosaurus) and the newly erected ichnotaxon Ruopodosaurus clava but differentiating it from other ankylosaurian tracks (Tetrapodosaurus isp.). Importantly, the new tracks are the first natural moulds (concave epirelief) found in Dinosaur Provincial Park, which, due to the unique geomorphology of the area, can only be recognised in outcrops where there are prominent sediment displacement rims. The new search image outlined here has already resulted in several subsequent trackway discoveries, and has the potential to transform ichnological studies in the Dinosaur Park Formation and related formations where badlands prevail.",
    url = "https://doi.org/10.1371/journal.pone.0324913",
    doi = "10.1371/journal.pone.0324913",
    number = "7",
    openalex = "W4412604206",
    pages = "e0324913",
    volume = "20",
    references = "doi1010160022519371901895, doi1010160022519373901847, doi101016jearscirev201304007, doi101016jtree200501010, doi101111brv12122, doi101139e93016, doi1016690883135120010160482ttoaco20co2, doi105281zenodo3725717, doi105860choice435902, openalexw659151049"
}

Abstract In 1855, Ferdinand Hayden collected a single tooth from the Judith River badlands of central Montana. Joseph Leidy named this specimen the following year as Troodon formosus. We describe troodontid material from the coeval Two Medicine Formation of Montana that compares closely to the recently resurrected and previously synonymized Stenonychosaurus inequalis from the lower Dinosaur Park Formation of Alberta. We uphold that synonymy but recognize T. formosus as the senior synonym. Troodon formosus is distinguished from other troodontids by a maxilla with an anteriorly more broadly rounded maxillary fenestra, low-angled nasal process with stepped anterior portion, large palatal shelf, and 23 teeth; more pronounced basioccipital tubera; L-shaped to triangular frontal; and relatively shorter metatarsal III with convex to flat anterior face at maximum breadth. Phylogenetic analysis places T. formosus within the Troodontinae, a clade with poor within-group resolution. The T. formosus holotype was diagnostic at time of description. Despite numerous complications over the taxon’s long history, the original name of 1856 has come to encompass a robust and specific species concept despite originally fragmentary material. Troodon formosus best satisfies the International Code of Zoological Nomenclature’s tenants of priority and stability. Recent proposals to re-establish Stenonychosaurus inequalis as the proper name encounter an equally problematic and undiagnostic type specimen. Instead of either of these types, we propose that material from the Two Medicine Formation (Museum of the Rockies, MOR 553) would best serve as a neotype for Troodon formosus.

@article{doi101017jpa202467,
    author = "Varricchio, David J. and Hogan, Jason D. and Gardner, Jacob D.",
    title = "Troodontid specimens from the Cretaceous Two Medicine Formation of Montana (USA) and the validity of Troodon formosus",
    year = "2025",
    journal = "Journal of Paleontology",
    abstract = "Abstract In 1855, Ferdinand Hayden collected a single tooth from the Judith River badlands of central Montana. Joseph Leidy named this specimen the following year as Troodon formosus. We describe troodontid material from the coeval Two Medicine Formation of Montana that compares closely to the recently resurrected and previously synonymized Stenonychosaurus inequalis from the lower Dinosaur Park Formation of Alberta. We uphold that synonymy but recognize T. formosus as the senior synonym. Troodon formosus is distinguished from other troodontids by a maxilla with an anteriorly more broadly rounded maxillary fenestra, low-angled nasal process with stepped anterior portion, large palatal shelf, and 23 teeth; more pronounced basioccipital tubera; L-shaped to triangular frontal; and relatively shorter metatarsal III with convex to flat anterior face at maximum breadth. Phylogenetic analysis places T. formosus within the Troodontinae, a clade with poor within-group resolution. The T. formosus holotype was diagnostic at time of description. Despite numerous complications over the taxon’s long history, the original name of 1856 has come to encompass a robust and specific species concept despite originally fragmentary material. Troodon formosus best satisfies the International Code of Zoological Nomenclature’s tenants of priority and stability. Recent proposals to re-establish Stenonychosaurus inequalis as the proper name encounter an equally problematic and undiagnostic type specimen. Instead of either of these types, we propose that material from the Two Medicine Formation (Museum of the Rockies, MOR 553) would best serve as a neotype for Troodon formosus.",
    url = "https://doi.org/10.1017/jpa.2024.67",
    doi = "10.1017/jpa.2024.67",
    openalex = "W4410330389",
    references = "doi104095105060"
}

Troodontidae is a family of small-bodied theropods known predominantly from Asia but are comparatively scarce in North America. In the Dinosaur Park Formation (DPF) of Alberta, Canada, they are known predominantly from isolated material, precluding taxonomic and ontogenetic precision for this clade. Previously never sampled histologically within the DPF, here we attempt to fill in gaps in our knowledge about the life histories of the clade in this formation by histologically surveying metatarsals, which are among the most abundant and identifiable troodontid elements in the DPF. We sampled 11 metatarsals (three metatarsal IIs, three metatarsal IIIs and five metatarsal IVs) of varying sizes and included three pathological individuals to describe the microanatomy of both healthy and pathological metatarsals, determine the ontogenetic status of each element and graph their pattern of growth. Osteohistology reveals that troodontid metatarsals grew and remodelled asymmetrically within the cortex, ceasing growth and remodelling primarily along articular surfaces and entheses. Pathological individuals ranged from displaying features of response to localised stress (chronic callus formation and avulsion/chip fracture) to extreme modification in response to trauma and inflammation at the distal joint. Only the latter appeared to be related to overall growth, suggesting the condition either developed early and stunted growth or another underlying cause was responsible for both the stunted growth and the resulting pathological features observed. Overall, tracking the growth of the specimens reveals that there are at least two growth trajectories within the DPF differentiated by the timing of major growth spurts and growth plateaus. Whether this represents sexual dimorphism, taxonomic diversity, or another form of variation warrants further investigation.

@article{doi101111joa14262,
    author = "Garros, Christiana and Powers, Mark J. and Dyer, Aaron D. and Currie, Philip J.",
    title = "Osteohistological analysis of metatarsals reveals new information on pathology and life history of troodontids from the Campanian Dinosaur Park Formation, Alberta, Canada",
    year = "2025",
    journal = "Journal of Anatomy",
    abstract = "Troodontidae is a family of small-bodied theropods known predominantly from Asia but are comparatively scarce in North America. In the Dinosaur Park Formation (DPF) of Alberta, Canada, they are known predominantly from isolated material, precluding taxonomic and ontogenetic precision for this clade. Previously never sampled histologically within the DPF, here we attempt to fill in gaps in our knowledge about the life histories of the clade in this formation by histologically surveying metatarsals, which are among the most abundant and identifiable troodontid elements in the DPF. We sampled 11 metatarsals (three metatarsal IIs, three metatarsal IIIs and five metatarsal IVs) of varying sizes and included three pathological individuals to describe the microanatomy of both healthy and pathological metatarsals, determine the ontogenetic status of each element and graph their pattern of growth. Osteohistology reveals that troodontid metatarsals grew and remodelled asymmetrically within the cortex, ceasing growth and remodelling primarily along articular surfaces and entheses. Pathological individuals ranged from displaying features of response to localised stress (chronic callus formation and avulsion/chip fracture) to extreme modification in response to trauma and inflammation at the distal joint. Only the latter appeared to be related to overall growth, suggesting the condition either developed early and stunted growth or another underlying cause was responsible for both the stunted growth and the resulting pathological features observed. Overall, tracking the growth of the specimens reveals that there are at least two growth trajectories within the DPF differentiated by the timing of major growth spurts and growth plateaus. Whether this represents sexual dimorphism, taxonomic diversity, or another form of variation warrants further investigation.",
    url = "https://doi.org/10.1111/joa.14262",
    doi = "10.1111/joa.14262",
    openalex = "W4409599580",
    references = "doi101038s41598021837455, doi101111joa14053, doi101139cjes20170034, doi101139cjes20200145, doi107717peerj10855"
}

Troodontids are small-bodied paravian theropod dinosaurs that are conspicuous for their close evolutionary relationship with modern birds and unique bauplan among Mesozoic non-avian theropods, part of which has been interpreted as suggestive of a distinctive ecological niche as highly cursorial predators who primarily hunted small prey items or of an increased portion of plant material in their diet compared to other theropods. Despite the increased interest in paleobiology of bird-like dinosaurs more recently, however, feeding biomechanics of troodontids remains largely uninvestigated. Here, the feeding and predatory behaviours of five troodontids are investigated, using beam theory on their mandibles. Mandibular strength profiles reveal that the anterior extremity of the jaws in troodontids, even in early-diverging forms, is better adapted to endure mediolateral and torsional loads compared to most other theropods such as dromaeosaurids. In later-diverging, relatively large-bodied taxa, the anterior half of the dentary is strengthened in terms of its mediolateral bending rigidity. Such unique profiles suggest the anterior part of the lower jaw played an important role in the life habits of troodontids. These results could be interpreted that the anterior region of the troodontid dentary was used to crop off plant material, or assisted in prey capture when the prey was subdued by the pes of an animal.

@article{doi1018261let5813,
    author = "Yun, Chan‐gyu",
    title = "Jaw biomechanics of Troodontidae and their implications for the palaeobiology of this lineage of bird-like theropod dinosaurs",
    year = "2025",
    journal = "Lethaia",
    abstract = "Troodontids are small-bodied paravian theropod dinosaurs that are conspicuous for their close evolutionary relationship with modern birds and unique bauplan among Mesozoic non-avian theropods, part of which has been interpreted as suggestive of a distinctive ecological niche as highly cursorial predators who primarily hunted small prey items or of an increased portion of plant material in their diet compared to other theropods. Despite the increased interest in paleobiology of bird-like dinosaurs more recently, however, feeding biomechanics of troodontids remains largely uninvestigated. Here, the feeding and predatory behaviours of five troodontids are investigated, using beam theory on their mandibles. Mandibular strength profiles reveal that the anterior extremity of the jaws in troodontids, even in early-diverging forms, is better adapted to endure mediolateral and torsional loads compared to most other theropods such as dromaeosaurids. In later-diverging, relatively large-bodied taxa, the anterior half of the dentary is strengthened in terms of its mediolateral bending rigidity. Such unique profiles suggest the anterior part of the lower jaw played an important role in the life habits of troodontids. These results could be interpreted that the anterior region of the troodontid dentary was used to crop off plant material, or assisted in prey capture when the prey was subdued by the pes of an animal.",
    url = "https://doi.org/10.18261/let.58.1.3",
    doi = "10.18261/let.58.1.3",
    openalex = "W4409689639",
    references = "doi101002spp21487, doi101139cjes20170034, doi101139cjes20200184, wang2025a"
}