Juvenile dinosaurs

Osborn, H.F. (1905): Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21: 259-265, DOI: 10.5281/zenodo.814935

@article{doi105281zenodo814935,
    author = "Osborn, Henry F.",
    title = "Tyrannosaurus And Other Cretaceous Carnivorous Dinosaurs",
    year = "1905",
    journal = "Zenodo (CERN European Organization for Nuclear Research)",
    abstract = "Osborn, H.F. (1905): Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21: 259-265, DOI: 10.5281/zenodo.814935",
    url = "https://doi.org/10.5281/zenodo.814935",
    doi = "10.5281/zenodo.814935",
    openalex = "W3113191843"
}

@article{openalexw2246336267,
    author = "Estes, Richard and Berberian, P.A. and Meszoely, Charles A. M.",
    title = "Lower vertebrates from the late Cretaceous Hell Creek Formationc McCone Countyc Montana",
    year = "1969",
    journal = "Breviora",
    openalex = "W2246336267"
}

The distribution of articulated remains of fossil vertebrates is not uniform within the Oldman Formation (Campanian, Cretaceous) of Dinosaur Provincial Park, Alberta. The mesofauna gradually declines in importance from the west to the east, but a corresponding decline in megafauna does not occur until the eastern limit of the park is reached. The mesofauna is also impoverished low in the exposed section, although the megafauna is as abundant there as in higher levels. Woody vegetation may have supported 88% of the megafaunal herbivore biomass. A fine-grained mosaic of several vegetational types was superimposed on a broader west–east gradient of marsh–forest with an abundant mesofauna to an open woodland dominated by hadrosaurids. High densities of large ectothermic dinosaurs would have made intensive use of available vegetation and profoundly influenced landscapes. Distributions of vertebrates in sedimentary units resulting from normal environmental gradients should be distinguished from those postulated to be associated with the onset of changes that brought the Mesozoic to a close.

@article{doi101139e78109,
    author = "Béland, Pierre and Russell, Dale A.",
    title = "Paleoecology of Dinosaur Provincial Park (Cretaceous), Alberta, interpreted from the distribution of articulated vertebrate remains",
    year = "1978",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The distribution of articulated remains of fossil vertebrates is not uniform within the Oldman Formation (Campanian, Cretaceous) of Dinosaur Provincial Park, Alberta. The mesofauna gradually declines in importance from the west to the east, but a corresponding decline in megafauna does not occur until the eastern limit of the park is reached. The mesofauna is also impoverished low in the exposed section, although the megafauna is as abundant there as in higher levels. Woody vegetation may have supported 88\% of the megafaunal herbivore biomass. A fine-grained mosaic of several vegetational types was superimposed on a broader west–east gradient of marsh–forest with an abundant mesofauna to an open woodland dominated by hadrosaurids. High densities of large ectothermic dinosaurs would have made intensive use of available vegetation and profoundly influenced landscapes. Distributions of vertebrates in sedimentary units resulting from normal environmental gradients should be distinguished from those postulated to be associated with the onset of changes that brought the Mesozoic to a close.",
    url = "https://doi.org/10.1139/e78-109",
    doi = "10.1139/e78-109",
    openalex = "W1992960775",
    references = "doi101007bf00345312, doi1010160031018271900447, doi101098rstb19710018, doi101111j136520281976tb00242x, doi101126science1874180947, doi1023073608, doi105281zenodo16298542, doi105962bhlpart22969, doi105962bhltitle130546"
}

@article{archibald1982upper,
    author = "Archibald, J. David and Butler, Robert F. and Lindsay, Everett H. and Clemens, William A. and Dingus, Lowell",
    title = "Upper Cretaceous–Paleocene biostratigraphy and magnetostratigraphy, Hell Creek and Tullock Formations, northeastern Montana",
    year = "1982",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1982)10<153:ucbamh>2.0.co;2",
    doi = "10.1130/0091-7613(1982)10<153:ucbamh>2.0.co;2",
    number = "3",
    openalex = "W2013405608",
    pages = "153",
    volume = "10"
}

@book{carpenter1982baby1,
    author = "Carpenter, K",
    title = "Baby dinosaurs from the Late Cretaceous Lance and Hell Creek Formations, and a description of a new species of theropod",
    year = "1982",
    publisher = "University of Wyoming Contributions to Geology, v. 20, p. 123-134",
    note = "talkorigins\_source = {true}; raw\_reference = {Carpenter, K., 1982, Baby dinosaurs from the Late Cretaceous Lance and Hell Creek Formations, and a description of a new species of theropod: University of Wyoming Contributions to Geology, v. 20, p. 123-134.}"
}

Carpenter, Kenneth (1982): Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod. Contributions to Geology, University of Wyoming 20: 123-134, DOI: 10.5281/zenodo.3238510

@article{s2cea06341f5800fb47a34129c480d7f0a7872d56c,
    author = "Carpenter, K.",
    title = "Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod",
    year = "1982",
    journal = "Rocky Mountain Geology",
    abstract = "Carpenter, Kenneth (1982): Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod. Contributions to Geology, University of Wyoming 20: 123-134, DOI: 10.5281/zenodo.3238510",
    url = "https://www.semanticscholar.org/paper/cea06341f5800fb47a34129c480d7f0a7872d56c",
    doi = "10.15468/gcrned",
    is_oa = "true",
    openalex = "W2346377510",
    semanticscholar_citation_count = "81",
    semanticscholar_id = "cea06341f5800fb47a34129c480d7f0a7872d56c"
}

Inaccurate stratigraphic correlations in the Hell Creek area, Montana, have led to the assumption that transitional vertebrate faunas (Bug Creek Anthills) exist in the latest Cretaceous, refuting a catastrophic turnover at the Cretaceous-Tertiary boundary. Establishment of the transitional faunas in Paleocene channels that cut down through the Cretaceous-Tertiary boundary renders the terrestrial faunal record compatible with the marine record and with catastrophic extinction.

@article{doi101126science22346411177,
    author = "Smit, Jan and van der Kaars, Sander",
    title = "Terminal Cretaceous Extinctions in the Hell Creek Area, Montana: Compatible with Catastrophic Extinction",
    year = "1984",
    journal = "Science",
    abstract = "Inaccurate stratigraphic correlations in the Hell Creek area, Montana, have led to the assumption that transitional vertebrate faunas (Bug Creek Anthills) exist in the latest Cretaceous, refuting a catastrophic turnover at the Cretaceous-Tertiary boundary. Establishment of the transitional faunas in Paleocene channels that cut down through the Cretaceous-Tertiary boundary renders the terrestrial faunal record compatible with the marine record and with catastrophic extinction.",
    url = "https://doi.org/10.1126/science.223.4641.1177",
    doi = "10.1126/science.223.4641.1177",
    openalex = "W1973856653",
    references = "alvarez1980extraterrestrial, doi1010160016703782903829, doi1010160195667182900313, doi101038288651a0, doi101073pnas802627, doi101126science2094459921, doi101126science2194584495, doi101126science21945911383, doi10113000917613198210153ucbamh20co2, doi101130spe190p329"
}

Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of dinosaurs, and Paleocene pollen. The top of this channel is 1.3 meters above the likely position of the iridium anomaly, the Cretaceous/Tertiary boundary.

@article{sloan1986gradual,
    author = "Sloan, Robert E. and Rigby, J. Keith and Van Valen, Leigh M. and Gabriel, Diane",
    title = "Gradual Dinosaur Extinction and Simultaneous Ungulate Radiation in the Hell Creek Formation",
    year = "1986",
    journal = "Science",
    abstract = "Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of dinosaurs, and Paleocene pollen. The top of this channel is 1.3 meters above the likely position of the iridium anomaly, the Cretaceous/Tertiary boundary.",
    url = "https://doi.org/10.1126/science.232.4750.629",
    doi = "10.1126/science.232.4750.629",
    number = "4750",
    pages = "629-633",
    volume = "232"
}

Exposures of the Hell Creek and Tullock formations in eastern Montana and the Ludlow Formation in western North Dakota allow detailed reconstruction of the paleoenvironments associated with the Cretaceous-Paleogene (K-P) faunal transition in the Western Interior of North America. Facies associations demonstrate an ancient meandering fluvial environment in which gleization in unstable, poorly drained flood plains modified incipient soils. Sedimentologic and pedologic features indicate that concurrent with the faunal transition that occurred in the region, the amount of standing water increased dramatically, changing the earliest Paleogene soils and landscape. Depositional environment imposes taphonomic constraints on interpretations of K-P faunas and floras. Contrary to recent reports, fossil assemblages in Hell Creek channel deposits are reworked; bone and sediment clasts of the channel fills have been subject to traction transport. Age estimations based on supposedly unreworked fossils in channel deposits are thus unreliable. The chronostratigraphic resolution of the sediments under study is to date simply not comparable to the resolution required by researchers of the K-P boundary. - from Author

@article{doi1023073514678,
    author = "Fastovsky, David E.",
    title = "Paleoenvironments of Vertebrate-Bearing Strata during the Cretaceous-Paleogene Transition, Eastern Montana and Western North Dakota",
    year = "1987",
    journal = "Palaios",
    abstract = "Exposures of the Hell Creek and Tullock formations in eastern Montana and the Ludlow Formation in western North Dakota allow detailed reconstruction of the paleoenvironments associated with the Cretaceous-Paleogene (K-P) faunal transition in the Western Interior of North America. Facies associations demonstrate an ancient meandering fluvial environment in which gleization in unstable, poorly drained flood plains modified incipient soils. Sedimentologic and pedologic features indicate that concurrent with the faunal transition that occurred in the region, the amount of standing water increased dramatically, changing the earliest Paleogene soils and landscape. Depositional environment imposes taphonomic constraints on interpretations of K-P faunas and floras. Contrary to recent reports, fossil assemblages in Hell Creek channel deposits are reworked; bone and sediment clasts of the channel fills have been subject to traction transport. Age estimations based on supposedly unreworked fossils in channel deposits are thus unreliable. The chronostratigraphic resolution of the sediments under study is to date simply not comparable to the resolution required by researchers of the K-P boundary. - from Author",
    url = "https://doi.org/10.2307/3514678",
    doi = "10.2307/3514678",
    openalex = "W2321183212",
    references = "doi1010160022169465901010, doi101016003101828790040x, doi1010160037073869900104, doi101111j136530911964tb00459x, doi101111j136530911965tb01561x, doi101111j136530911979tb00935x, doi101126science2244651867, doi10130674d716cc2b2111d78648000102c1865d, doi10130674d71f322b2111d78648000102c1865d, harms1982structure"
}

@incollection{rigby1989the,
    author = "Rigby, J. Keith",
    title = "The Cretaceous-Tertiary boundary of the Bug Creek drainage: Hell Creek and Tullock formations, McCone and Garfield Counties, Montana",
    year = "1989",
    booktitle = "Mesozoic/Cenozoic Vertebrate Paleontology: Classic Localities, Contemporary Approaches. Salt Lake City, Utah to Billings, Montana, July 19–27, 1989",
    url = "https://doi.org/10.1029/ft322p0067",
    doi = "10.1029/ft322p0067",
    openalex = "W1576237705",
    pages = "67-73",
    references = "alvarez1980extraterrestrial, archibald1982upper, doi101029eo067i035p00649, doi1010631881078, doi101126science1483667220, doi101126science22346411135, doi101126science22546661030, doi101126science2314739714, doi1023073514678, sloan1986gradual"
}

@article{lofgren1990reworking,
    author = "Lofgren, Donald L. and Hotton, Carol L. and Runkel, Anthony C.",
    title = "Reworking of Cretaceous dinosaurs into Paleocene channel, deposits, upper Hell Creek Formation, Montana",
    year = "1990",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1990)018<0874:rocdip>2.3.co;2",
    doi = "10.1130/0091-7613(1990)018<0874:rocdip>2.3.co;2",
    number = "9",
    openalex = "W2059769021",
    pages = "874",
    volume = "18"
}

Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.

@article{doi101126science2725264986,
    author = "Sereno, Paul C. and Dutheil, Didier B. and Iarochène, Mohamed and Larsson, Hans C. E. and Lyon, Gabrielle H. and Magwene, Paul M. and Sidor, Christian A. and Varricchio, David J. and Wilson, Jeffrey A.",
    title = "Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation",
    year = "1996",
    journal = "Science",
    abstract = "Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.",
    url = "https://doi.org/10.1126/science.272.5264.986",
    doi = "10.1126/science.272.5264.986",
    openalex = "W2013182835",
    references = "coria1995a, doi101007bf02987808, doi101016s0016699509900389, doi101038377224a0, doi101126science2665183267, doi102113gssgfbulliv2335, doi1023072421859, doi105281zenodo1040385, doi105962p226819, openalexw1426920053, openalexw2603028126"
}

Late Cretaceous trace fossils from the Two Medicine Formation of Montana are interpreted as herbivorous dinosaur feces reworked by scarabaeine dung beetles. These irregular blocks of comminuted plant material occur in isolated patches in fluvial flood plain sediments near dinosaur bone beds and nesting grounds. Numerous burrows in and around the specimens indicate significant invertebrate activity which suggests intense competition for a rich food resource. Some of the burrows are backfilled with organic matter that had been translocated from the organic mass (dung pat) into the adjacent sediment. Paracoprid dung beetles are the only extant organisms known to make similar caches. These unique ichnofossils provide evidence for commensal interactions between dung beetles, herbivorous dinosaurs, and conifers. This find also reveals a pathway through which fecal resources were recycled and suggests that scarabs evolved coprophagy through association with dinosaurs.

@article{doi1023073515235,
    author = "Chin, Karen and Gill, Bruce D.",
    title = "Dinosaurs, Dung Beetles, and Conifers: Participants in a Cretaceous Food Web",
    year = "1996",
    journal = "Palaios",
    abstract = "Late Cretaceous trace fossils from the Two Medicine Formation of Montana are interpreted as herbivorous dinosaur feces reworked by scarabaeine dung beetles. These irregular blocks of comminuted plant material occur in isolated patches in fluvial flood plain sediments near dinosaur bone beds and nesting grounds. Numerous burrows in and around the specimens indicate significant invertebrate activity which suggests intense competition for a rich food resource. Some of the burrows are backfilled with organic matter that had been translocated from the organic mass (dung pat) into the adjacent sediment. Paracoprid dung beetles are the only extant organisms known to make similar caches. These unique ichnofossils provide evidence for commensal interactions between dung beetles, herbivorous dinosaurs, and conifers. This find also reveals a pathway through which fecal resources were recycled and suggests that scarabs evolved coprophagy through association with dinosaurs.",
    url = "https://doi.org/10.2307/3515235",
    doi = "10.2307/3515235",
    openalex = "W1966939491",
    references = "doi101038282296a0, doi101139e78109"
}

The small Upper Cretaceous ornithopod dinosaur Orodromeus makelai, possesses many tooth traits reminiscent of Triassic fabrosaurs. Determining whether these teeth were retained from a primitive lineage or independently derived within Orodromeus prompted a critical examination and ultimate revision of hypsilophodontid and basal ornithopod phytogeny. The revision of the Hypsilophodontidae resulted in a dissolution of the group into a pectinate grade of dinosaurs with a concommitment trend in increased size and herbivorous efficiency. Phylogenetic context reveals Orodromeus as nested within ornithopods with established herbivorous adaptations. Anomalous triangular teeth and high angle occlusion in Orodromeus is thought indicative of a shift to insectivory, possibly retained from the neonate condition. Other juvenile conditions, such as large orbits and unfused elements in mature specimens, together with rapid deacceleration of radial femoral bone growth through ontogeny is suggestive of neoteny. Continued histological studies of fossil taxa, together with a clear understanding of relationships, would help to identify heterochronic shifts in evolution. Analysis of 20 taxa, using 124 morphological characters, indicates the pandemic distribution of small ornithopod taxa occurred prior to the Upper Jurassic. Although hadrosaurs diversified in the Upper Cretaceous as did angiosperms, most all major herbivorous adaptations were in place within ornithopods prior to the first occurrence of angiosperms in North America.

@phdthesis{openalexw225597919,
    author = "Scheetz, Rodney D.",
    title = "Osteology of Orodromeus makelai and the phylogeny of basal ornithopod dinosaurs",
    year = "1999",
    booktitle = "Montana State University ScholarWorks (Montana State University)",
    abstract = "The small Upper Cretaceous ornithopod dinosaur Orodromeus makelai, possesses many tooth traits reminiscent of Triassic fabrosaurs. Determining whether these teeth were retained from a primitive lineage or independently derived within Orodromeus prompted a critical examination and ultimate revision of hypsilophodontid and basal ornithopod phytogeny. The revision of the Hypsilophodontidae resulted in a dissolution of the group into a pectinate grade of dinosaurs with a concommitment trend in increased size and herbivorous efficiency. Phylogenetic context reveals Orodromeus as nested within ornithopods with established herbivorous adaptations. Anomalous triangular teeth and high angle occlusion in Orodromeus is thought indicative of a shift to insectivory, possibly retained from the neonate condition. Other juvenile conditions, such as large orbits and unfused elements in mature specimens, together with rapid deacceleration of radial femoral bone growth through ontogeny is suggestive of neoteny. Continued histological studies of fossil taxa, together with a clear understanding of relationships, would help to identify heterochronic shifts in evolution. Analysis of 20 taxa, using 124 morphological characters, indicates the pandemic distribution of small ornithopod taxa occurred prior to the Upper Jurassic. Although hadrosaurs diversified in the Upper Cretaceous as did angiosperms, most all major herbivorous adaptations were in place within ornithopods prior to the first occurrence of angiosperms in North America.",
    url = "https://openalex.org/W225597919",
    openalex = "W225597919"
}

@article{doi10136002tb9031,
    author = "Swisher, Carl C. and Wang, Xiaolin and Zhou, Zhonghe and Wang, Yuan and Jin, Fan and Zhang, Jiangyong and Xu, Xing and Zhang, Fucheng and Wang, Yuan",
    title = "Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning,China:New 40Ar÷39Ar dating of the Yixian and Tuchengzi Formations",
    year = "2002",
    journal = "Science Bulletin",
    url = "https://doi.org/10.1360/02tb9031",
    doi = "10.1360/02tb9031",
    openalex = "W2422935836",
    references = "doi101126science29054981955"
}

Synopsis The dinosaurs of the Hateg Basin of Transylvania (late Maastrichtian; western Romania) include Theropoda, Sauropoda, Ornithopoda and Ankylosauria. Of these, one of the most enigmatic taxa is the ornithopod that Franz Baron Nopcsa originally described as Mochlodon suessi and M. robustus in 1902. These two species have come to be regarded as a single species of Rhabdodon, R. robustus, which is distinct from R. priscus from the Late Cretaceous of southern France and northern Spain. This study provides a detailed anatomical revision of the Rhabdodon material that was described originally by Nopcsa during the early decades of the 20th century. It also adds information on material discovered in the Hateg area of Romania since the 1930s. A phylogenetic analysis of basal euornithopods indicates that the non‐hadrosaurid material from Hateg comprises two distinct, but congeneric, species. These two species can be distinguished unambiguously from R. priscus. A new genus Zalmoxes is established for the Romanian ornithopod, comprising Z. robustus comb. nov. (the type‐species of the genus) and Z. shqiperorum sp. nov. Phylogenetic analysis indicates that the two species of Zalmoxes and R. priscus are united in the monophyletic clade Rhabdodontidae (nov.). Rhabdodontidae constitutes the sibling clade to Iguanodontia. R. septimanicus, M. suessi, and the Villeveyrac Rhabdodon also appear to be members of Rhabdodontidae. The evolutionary implications of this phylogenetic analysis include the recognition of a ghost lineage, extending from the most recent common ancestor of Rhabdodontidae and Iguanodontia, which extends for 73 million years. This extraordinarily long ghost lineage duration may reflect considerable gaps in the history of this group or the geographical isolation of Rhabdodontidae in Europe during much of the Cretaceous period. The area of origin of the Rhabdodontidae + Iguanodontia clade may be North America, while the common ancestor of Rhabdodontidae dispersed to Europe, at that time a marine‐dominated region with tectonically‐active terrestrial habitats. Adult individuals of Z. robustus are smaller than either of its two closest relatives, Z. shqiperorum and R. priscus, within the Rhabdodontidae, or with many species of Iguanodontia and, therefore, is considered a possible paedomorphic dwarf.

@article{doi101017s1477201903001032,
    author = "Weishampel, David B. and Jianu, Coralia‐Maria and Csiki‐Sava, Zoltán and Norman, David",
    title = "Osteology and phylogeny of Zalmoxes (n. g.), an unusual Euornithopod dinosaur from the latest Cretaceous of Romania",
    year = "2003",
    journal = "Journal of Systematic Palaeontology",
    abstract = "Synopsis The dinosaurs of the Hateg Basin of Transylvania (late Maastrichtian; western Romania) include Theropoda, Sauropoda, Ornithopoda and Ankylosauria. Of these, one of the most enigmatic taxa is the ornithopod that Franz Baron Nopcsa originally described as Mochlodon suessi and M. robustus in 1902. These two species have come to be regarded as a single species of Rhabdodon, R. robustus, which is distinct from R. priscus from the Late Cretaceous of southern France and northern Spain. This study provides a detailed anatomical revision of the Rhabdodon material that was described originally by Nopcsa during the early decades of the 20th century. It also adds information on material discovered in the Hateg area of Romania since the 1930s. A phylogenetic analysis of basal euornithopods indicates that the non‐hadrosaurid material from Hateg comprises two distinct, but congeneric, species. These two species can be distinguished unambiguously from R. priscus. A new genus Zalmoxes is established for the Romanian ornithopod, comprising Z. robustus comb. nov. (the type‐species of the genus) and Z. shqiperorum sp. nov. Phylogenetic analysis indicates that the two species of Zalmoxes and R. priscus are united in the monophyletic clade Rhabdodontidae (nov.). Rhabdodontidae constitutes the sibling clade to Iguanodontia. R. septimanicus, M. suessi, and the Villeveyrac Rhabdodon also appear to be members of Rhabdodontidae. The evolutionary implications of this phylogenetic analysis include the recognition of a ghost lineage, extending from the most recent common ancestor of Rhabdodontidae and Iguanodontia, which extends for 73 million years. This extraordinarily long ghost lineage duration may reflect considerable gaps in the history of this group or the geographical isolation of Rhabdodontidae in Europe during much of the Cretaceous period. The area of origin of the Rhabdodontidae + Iguanodontia clade may be North America, while the common ancestor of Rhabdodontidae dispersed to Europe, at that time a marine‐dominated region with tectonically‐active terrestrial habitats. Adult individuals of Z. robustus are smaller than either of its two closest relatives, Z. shqiperorum and R. priscus, within the Rhabdodontidae, or with many species of Iguanodontia and, therefore, is considered a possible paedomorphic dwarf.",
    url = "https://doi.org/10.1017/s1477201903001032",
    doi = "10.1017/s1477201903001032",
    openalex = "W2167550757",
    references = "doi10100797836426953391, doi10103835059070, doi10108002724634199010011815, doi101086284406, doi101098rspl18870117, doi101111j109636421998tb02533x, doi101126science27352791204, doi102307jctvxkn7tk, doi102475ajss321125417, doi105479si00963801361666197, openalexw51761775, openalexw575814759"
}

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"
}

The Nanxiong and Shanghu Formations of southeastern China span the KT boundary interval and preserve an important paleontological record. A 1285‐m section across the KT boundary was measured, and lithological units were documented and sampled. Strata were deposited in alluvial fan/playa mudflat environments in a highly seasonal, semiarid climate. Previous workers placed the KT boundary at the Nanxiong/Shanghu formational contact. The uppermost Nanxiong and lowermost Shanghu Formations contain an assemblage of dinosaur egg fragments and Tertiary fossils, which led to the notion that dinosaurs survived into the Paleocene. On the basis of our results, we argue that the mixed KT assemblage is a result of debris flows reworking Cretaceous fossils. Depositional environments and paleoclimate did not change significantly across the KT boundary.

@article{doi101086379695,
    author = "Buck, Brenda J. and Hanson, Andrew D. and Hengst, Richard A. and Hu, Shusheng",
    title = "“Tertiary Dinosaurs” in the Nanxiong Basin, Southern China, Are Reworked from the Cretaceous",
    year = "2004",
    journal = "The Journal of Geology",
    abstract = "The Nanxiong and Shanghu Formations of southeastern China span the KT boundary interval and preserve an important paleontological record. A 1285‐m section across the KT boundary was measured, and lithological units were documented and sampled. Strata were deposited in alluvial fan/playa mudflat environments in a highly seasonal, semiarid climate. Previous workers placed the KT boundary at the Nanxiong/Shanghu formational contact. The uppermost Nanxiong and lowermost Shanghu Formations contain an assemblage of dinosaur egg fragments and Tertiary fossils, which led to the notion that dinosaurs survived into the Paleocene. On the basis of our results, we argue that the mixed KT assemblage is a result of debris flows reworking Cretaceous fossils. Depositional environments and paleoclimate did not change significantly across the KT boundary.",
    url = "https://doi.org/10.1086/379695",
    doi = "10.1086/379695",
    openalex = "W1991908329",
    references = "alvarez1980extraterrestrial, doi101016s0012821x00002387, doi101038359819a0, doi101086629677, doi1010970001069419660500000001, doi101111j136530911989tb00608x, doi1011300016760619931050129cop23co2, doi1011300091761319910190867ccapct23co2, doi101130spe203p1, lofgren1990reworking, sloan1986gradual"
}

The armor-plated dinosaur Ankylosaurus magniventris is redescribed based on specimens from the Hell Creek Formation of northeastern Montana, USA., Lance Formation of Wyoming, USA., and from the Scollard Formation of south-central Alberta, Canada. Except for brief descriptions, most of these specimens have not been described in detail. Ankylosaurus is one of the largest known ankylosaurids, having an estimated length of up to 6.25 m (20.5 ft). It is characterized by a long, low skull having very prominent cranial “horns” that project laterally or dorsolaterally. The body armor includes a large half-ring that sat across the base of the neck and shoulders and a large, low tail club.

@article{doi101139e04043,
    author = "Carpenter, K.",
    title = "Redescription of Ankylosaurus magniventris Brown 1908 (Ankylosauridae) from the Upper Cretaceous of the Western Interior of North America",
    year = "2004",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The armor-plated dinosaur Ankylosaurus magniventris is redescribed based on specimens from the Hell Creek Formation of northeastern Montana, USA., Lance Formation of Wyoming, USA., and from the Scollard Formation of south-central Alberta, Canada. Except for brief descriptions, most of these specimens have not been described in detail. Ankylosaurus is one of the largest known ankylosaurids, having an estimated length of up to 6.25 m (20.5 ft). It is characterized by a long, low skull having very prominent cranial “horns” that project laterally or dorsolaterally. The body armor includes a large half-ring that sat across the base of the neck and shoulders and a large, low tail club.",
    url = "https://www.semanticscholar.org/paper/7d3bce5a7f19fef32edb1d8f1342bb7bba2fd4b4",
    doi = "10.1139/E04-043",
    is_oa = "true",
    number = "8",
    pages = "961-986",
    semanticscholar_citation_count = "97",
    semanticscholar_id = "7d3bce5a7f19fef32edb1d8f1342bb7bba2fd4b4",
    volume = "41"
}

Contributors Preface Acknowledgments I. Beaked Dinosaurs: The Ornithopods 1. Callovosaurus leedsi, the Earliest Dryosaurid Dinosaur (Ornithischia: Euornithopoda) from the Middle Jurassic of England Jose Ignacio Ruiz-Omenaca, Xabier Pereda Suberbiola, and Peter M. Galton 2. Teeth of Ornithischian Dinosaurs (Mostly Ornithopoda) from the Morrison Formation (Upper Jurassic) of the Western United States Peter M. Galton 3. A Description of a New Ornithopod from the Lytle Member of the Purgatoire Formation (Lower Cretaceous) and a Reassessment of the Skull of Camptosaurus Kathleen Brill and Kenneth Carpenter 4. Turning the Old into the New: A Separate Genus for the Gracile Iguanodont from the Wealden of England Gregory S. Paul 5. A Possible New Basal Hadrosaur from the Lower Cretaceous Cedar Mountain Formation of Eastern Utah David Gilpin, Tony DiCroce, and Kenneth Carpenter 6. Postcranial Osteology of the Hadrosaurid Dinosaur Brachylophosaurus canadensis from the Late Cretaceous of Montana Albert Prieto-Marquez 7. Leonardo, a Mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River Formation of Montana Nate L. Murphy, David Trexler, and Mark Thompson 8. Discussion of Character Analysis of the Appendicular Anatomy in Campanian and Maastrichtian North American Hadrosaurids-Variation and Ontogeny Michael K. Brett-Surman and Jonathan R. Wagner 9. Osteochondrosis in Late Cretaceous Hadrosauria: A Manifestation of Ontologic Failure Bruce Rothschild and Darren H. Tanke 10. Deciphering Duckbills: A History in Nomenclature Benjamin S. Creisler II. Horned Dinosaurs: Ceratopsians 11. Cranial Anatomy and Biogeography of the First Leptoceratops gracilis (Dinosauria: Ornithischia) Specimens from the Hell Creek Formation, Southeast Montana Christopher J. Ott 12. Cranial Osteology and Phylogenetic Relationships of the Chasmosaurine Ceratopsid Torosaurus latus Andrew A. Farke 13. Growth and Population Age Structure in the Horned Dinosaur Chasmosaurus Thomas M. Lehman 14. Bone Resorption, Bone Lesions, and Extracranial Fenestrae in Ceratopsid Dinosaurs: A Preliminary Assessment Darren H. Tanke and Andrew A. Farke 15. Bison alticornis and O. C. Marsh's Early Views on Ceratopsians Kenneth Carpenter Index

@book{openalexw597685939,
    author = "Carpenter, Kenneth",
    title = "Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs",
    year = "2006",
    booktitle = "Project Muse (Johns Hopkins University)",
    abstract = "Contributors Preface Acknowledgments I. Beaked Dinosaurs: The Ornithopods 1. Callovosaurus leedsi, the Earliest Dryosaurid Dinosaur (Ornithischia: Euornithopoda) from the Middle Jurassic of England Jose Ignacio Ruiz-Omenaca, Xabier Pereda Suberbiola, and Peter M. Galton 2. Teeth of Ornithischian Dinosaurs (Mostly Ornithopoda) from the Morrison Formation (Upper Jurassic) of the Western United States Peter M. Galton 3. A Description of a New Ornithopod from the Lytle Member of the Purgatoire Formation (Lower Cretaceous) and a Reassessment of the Skull of Camptosaurus Kathleen Brill and Kenneth Carpenter 4. Turning the Old into the New: A Separate Genus for the Gracile Iguanodont from the Wealden of England Gregory S. Paul 5. A Possible New Basal Hadrosaur from the Lower Cretaceous Cedar Mountain Formation of Eastern Utah David Gilpin, Tony DiCroce, and Kenneth Carpenter 6. Postcranial Osteology of the Hadrosaurid Dinosaur Brachylophosaurus canadensis from the Late Cretaceous of Montana Albert Prieto-Marquez 7. Leonardo, a Mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River Formation of Montana Nate L. Murphy, David Trexler, and Mark Thompson 8. Discussion of Character Analysis of the Appendicular Anatomy in Campanian and Maastrichtian North American Hadrosaurids-Variation and Ontogeny Michael K. Brett-Surman and Jonathan R. Wagner 9. Osteochondrosis in Late Cretaceous Hadrosauria: A Manifestation of Ontologic Failure Bruce Rothschild and Darren H. Tanke 10. Deciphering Duckbills: A History in Nomenclature Benjamin S. Creisler II. Horned Dinosaurs: Ceratopsians 11. Cranial Anatomy and Biogeography of the First Leptoceratops gracilis (Dinosauria: Ornithischia) Specimens from the Hell Creek Formation, Southeast Montana Christopher J. Ott 12. Cranial Osteology and Phylogenetic Relationships of the Chasmosaurine Ceratopsid Torosaurus latus Andrew A. Farke 13. Growth and Population Age Structure in the Horned Dinosaur Chasmosaurus Thomas M. Lehman 14. Bone Resorption, Bone Lesions, and Extracranial Fenestrae in Ceratopsid Dinosaurs: A Preliminary Assessment Darren H. Tanke and Andrew A. Farke 15. Bison alticornis and O. C. Marsh's Early Views on Ceratopsians Kenneth Carpenter Index",
    openalex = "W597685939"
}

Contributors Preface Acknowledgments I. Beaked Dinosaurs: The Ornithopods 1. Callovosaurus leedsi, the Earliest Dryosaurid Dinosaur (Ornithischia: Euornithopoda) from the Middle Jurassic of England Jose Ignacio Ruiz-Omenaca, Xabier Pereda Suberbiola, and Peter M. Galton 2. Teeth of Ornithischian Dinosaurs (Mostly Ornithopoda) from the Morrison Formation (Upper Jurassic) of the Western United States Peter M. Galton 3. A Description of a New Ornithopod from the Lytle Member of the Purgatoire Formation (Lower Cretaceous) and a Reassessment of the Skull of Camptosaurus Kathleen Brill and Kenneth Carpenter 4. Turning the Old into the New: A Separate Genus for the Gracile Iguanodont from the Wealden of England Gregory S. Paul 5. A Possible New Basal Hadrosaur from the Lower Cretaceous Cedar Mountain Formation of Eastern Utah David Gilpin, Tony DiCroce, and Kenneth Carpenter 6. Postcranial Osteology of the Hadrosaurid Dinosaur Brachylophosaurus canadensis from the Late Cretaceous of Montana Albert Prieto-Marquez 7. Leonardo, a Mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River Formation of Montana Nate L. Murphy, David Trexler, and Mark Thompson 8. Discussion of Character Analysis of the Appendicular Anatomy in Campanian and Maastrichtian North American Hadrosaurids-Variation and Ontogeny Michael K. Brett-Surman and Jonathan R. Wagner 9. Osteochondrosis in Late Cretaceous Hadrosauria: A Manifestation of Ontologic Failure Bruce Rothschild and Darren H. Tanke 10. Deciphering Duckbills: A History in Nomenclature Benjamin S. Creisler II. Horned Dinosaurs: Ceratopsians 11. Cranial Anatomy and Biogeography of the First Leptoceratops gracilis (Dinosauria: Ornithischia) Specimens from the Hell Creek Formation, Southeast Montana Christopher J. Ott 12. Cranial Osteology and Phylogenetic Relationships of the Chasmosaurine Ceratopsid Torosaurus latus Andrew A. Farke 13. Growth and Population Age Structure in the Horned Dinosaur Chasmosaurus Thomas M. Lehman 14. Bone Resorption, Bone Lesions, and Extracranial Fenestrae in Ceratopsid Dinosaurs: A Preliminary Assessment Darren H. Tanke and Andrew A. Farke 15. Bison alticornis and O. C. Marsh's Early Views on Ceratopsians Kenneth Carpenter Index

@article{s275130bec4b7de57fce9bef0ec8999fa1f29d33c4,
    author = "Carpenter, K.",
    title = "Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs",
    year = "2006",
    booktitle = "Project Muse (Johns Hopkins University)",
    abstract = "Contributors Preface Acknowledgments I. Beaked Dinosaurs: The Ornithopods 1. Callovosaurus leedsi, the Earliest Dryosaurid Dinosaur (Ornithischia: Euornithopoda) from the Middle Jurassic of England Jose Ignacio Ruiz-Omenaca, Xabier Pereda Suberbiola, and Peter M. Galton 2. Teeth of Ornithischian Dinosaurs (Mostly Ornithopoda) from the Morrison Formation (Upper Jurassic) of the Western United States Peter M. Galton 3. A Description of a New Ornithopod from the Lytle Member of the Purgatoire Formation (Lower Cretaceous) and a Reassessment of the Skull of Camptosaurus Kathleen Brill and Kenneth Carpenter 4. Turning the Old into the New: A Separate Genus for the Gracile Iguanodont from the Wealden of England Gregory S. Paul 5. A Possible New Basal Hadrosaur from the Lower Cretaceous Cedar Mountain Formation of Eastern Utah David Gilpin, Tony DiCroce, and Kenneth Carpenter 6. Postcranial Osteology of the Hadrosaurid Dinosaur Brachylophosaurus canadensis from the Late Cretaceous of Montana Albert Prieto-Marquez 7. Leonardo, a Mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River Formation of Montana Nate L. Murphy, David Trexler, and Mark Thompson 8. Discussion of Character Analysis of the Appendicular Anatomy in Campanian and Maastrichtian North American Hadrosaurids-Variation and Ontogeny Michael K. Brett-Surman and Jonathan R. Wagner 9. Osteochondrosis in Late Cretaceous Hadrosauria: A Manifestation of Ontologic Failure Bruce Rothschild and Darren H. Tanke 10. Deciphering Duckbills: A History in Nomenclature Benjamin S. Creisler II. Horned Dinosaurs: Ceratopsians 11. Cranial Anatomy and Biogeography of the First Leptoceratops gracilis (Dinosauria: Ornithischia) Specimens from the Hell Creek Formation, Southeast Montana Christopher J. Ott 12. Cranial Osteology and Phylogenetic Relationships of the Chasmosaurine Ceratopsid Torosaurus latus Andrew A. Farke 13. Growth and Population Age Structure in the Horned Dinosaur Chasmosaurus Thomas M. Lehman 14. Bone Resorption, Bone Lesions, and Extracranial Fenestrae in Ceratopsid Dinosaurs: A Preliminary Assessment Darren H. Tanke and Andrew A. Farke 15. Bison alticornis and O. C. Marsh's Early Views on Ceratopsians Kenneth Carpenter Index",
    url = "https://www.semanticscholar.org/paper/75130bec4b7de57fce9bef0ec8999fa1f29d33c4",
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Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.

@article{doi101371journalpone0001230,
    author = "Sereno, Paul C. and Wilson, Jeffrey A. and Witmer, Lawrence M. and Whitlock, John A. and Maga, Abdoulaye and Idé, Oumarou and Rowe, Timothy A.",
    title = "Structural Extremes in a Cretaceous Dinosaur",
    year = "2007",
    journal = "PLoS ONE",
    abstract = "Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.",
    url = "https://doi.org/10.1371/journal.pone.0001230",
    doi = "10.1371/journal.pone.0001230",
    openalex = "W2111030938",
    references = "doi10100797844317693306, doi101017cbo9780511536045, doi101017s0094837300007557, doi101038274661a0, doi101038nature02048, doi101046j10963642200200029x, doi101073pnas932514623, doi10108002724634199810011115, doi101126science1118806, doi101525california97805202462320010001, doi105860choice260307, doi105962bhltitle102117, doi105962bhltitle60562, doi105962p234818, larsson2000forebrain, openalexw2983381470, openalexw2989049194"
}

The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125-80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR.

@article{doi101098rspb20080715,
    author = "Lloyd, Graeme T. and Davis, Katie E. and Pisani, Davide and Tarver, James E. and Ruta, Marcello and Sakamoto, Manabu and Hone, David W. E. and Jennings, Rachel and Benton, Michael J.",
    title = "Dinosaurs and the Cretaceous Terrestrial Revolution",
    year = "2008",
    journal = "Proceedings of the Royal Society B Biological Sciences",
    abstract = "The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125-80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR.",
    url = "https://doi.org/10.1098/rspb.2008.0715",
    doi = "10.1098/rspb.2008.0715",
    openalex = "W2131872692",
    references = "doi101007978140206754912413, doi101017cbo9780511536045, doi101038274661a0, doi101038nature05634, doi101046j14610248200100230x, doi101073pnas0606028103, doi101073pnas111144698, doi101093bioinformatics124357, doi101111j109600311999tb00277x, doi101126science1118806, doi101126science1144066, doi101159000452856, doi1015159780691224244, doi101525california97805202420980010001, doi101525california97805202462320010001, openalexw2989049194, openalexw3217097258, sloan1986gradual, smith2007marine"
}

Questions related to dinosaur behavior can be difficult to answer conclusively by using morphological studies alone. As a complement to these approaches, carbon and oxygen isotope ratios of tooth enamel can provide insight into habitat and dietary preferences of herbivorous dinosaurs. This approach is based on the isotopic variability in plant material and in surface waters of the past, which is in turn reflected by carbon and oxygen isotope ratios of animals that ingested the organic matter or drank the water. Thus, it has the potential to identify and characterize dietary and habitat preferences for coexisting taxa. In this study, stable isotope ratios from coexisting hadrosaurian and ceratopsian dinosaurs of the Hell Creek Formation of North Dakota are compared for four different stratigraphic levels. Isotopic offsets between tooth enamel and tooth dentine, as well as taxonomic differences in means and in patterns of isotopic data among taxa, indicate that primary paleoecological information is preserved. The existence of taxonomic offsets also provides the first direct evidence for dietary niche partitioning among these herbivorous dinosaur taxa. Of particular interest is the observation that the nature of this partitioning changes over time: for some localities ceratopsian dinosaurs have higher carbon and oxygen isotope ratios than hadrosaurs, indicating a preference for plants living in open settings near the coast, whereas for other localities isotope ratios are lower, indicating a preference for plants in the understory of forests. In most cases the isotope ratios among hadrosaurs are similar and are interpreted to represent a dietary preference for plants of the forest canopy. The inferred differences in ceratopsian behavior are suggested to represent a change in vegetation cover and hence habitat availability in response to sea level change or to the position of river distributaries. Given our current lack of taxonomic resolution, it is not possible to determine if dietary and habitat preferences inferred from stable isotope data are associated with single, or multiple, species of hadrosaurian/ceratopsian dinosaurs.

@article{doi101666080201,
    author = "Fricke, Henry and Pearson, Dean A.",
    title = "Stable isotope evidence for changes in dietary niche partitioning among hadrosaurian and ceratopsian dinosaurs of the Hell Creek Formation, North Dakota",
    year = "2008",
    journal = "Paleobiology",
    abstract = "Questions related to dinosaur behavior can be difficult to answer conclusively by using morphological studies alone. As a complement to these approaches, carbon and oxygen isotope ratios of tooth enamel can provide insight into habitat and dietary preferences of herbivorous dinosaurs. This approach is based on the isotopic variability in plant material and in surface waters of the past, which is in turn reflected by carbon and oxygen isotope ratios of animals that ingested the organic matter or drank the water. Thus, it has the potential to identify and characterize dietary and habitat preferences for coexisting taxa. In this study, stable isotope ratios from coexisting hadrosaurian and ceratopsian dinosaurs of the Hell Creek Formation of North Dakota are compared for four different stratigraphic levels. Isotopic offsets between tooth enamel and tooth dentine, as well as taxonomic differences in means and in patterns of isotopic data among taxa, indicate that primary paleoecological information is preserved. The existence of taxonomic offsets also provides the first direct evidence for dietary niche partitioning among these herbivorous dinosaur taxa. Of particular interest is the observation that the nature of this partitioning changes over time: for some localities ceratopsian dinosaurs have higher carbon and oxygen isotope ratios than hadrosaurs, indicating a preference for plants living in open settings near the coast, whereas for other localities isotope ratios are lower, indicating a preference for plants in the understory of forests. In most cases the isotope ratios among hadrosaurs are similar and are interpreted to represent a dietary preference for plants of the forest canopy. The inferred differences in ceratopsian behavior are suggested to represent a change in vegetation cover and hence habitat availability in response to sea level change or to the position of river distributaries. Given our current lack of taxonomic resolution, it is not possible to determine if dietary and habitat preferences inferred from stable isotope data are associated with single, or multiple, species of hadrosaurian/ceratopsian dinosaurs.",
    url = "https://doi.org/10.1666/08020.1",
    doi = "10.1666/08020.1",
    openalex = "W2163744230",
    references = "doi101016jpalaeo200401006, doi1023073514678"
}

Dracorex hogwartsia (juvenile) and Stygimoloch spinifer (subadult) are reinterpreted as younger growth stages of Pachycephalosaurus wyomingensis (adult). This synonymy reduces the number of pachycephalosaurid taxa from the Upper Cretaceous of North America and demonstrates the importance of cranial ontogeny in evaluating dinosaur diversity and taxonomy. These growth stages reflect a continuum rather than specific developmental steps defined by "known" terminal morphologies.

@article{doi101371journalpone0007626,
    author = "Horner, John R. and Goodwin, Mark B.",
    title = "Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus",
    year = "2009",
    journal = "PLoS ONE",
    abstract = {Dracorex hogwartsia (juvenile) and Stygimoloch spinifer (subadult) are reinterpreted as younger growth stages of Pachycephalosaurus wyomingensis (adult). This synonymy reduces the number of pachycephalosaurid taxa from the Upper Cretaceous of North America and demonstrates the importance of cranial ontogeny in evaluating dinosaur diversity and taxonomy. These growth stages reflect a continuum rather than specific developmental steps defined by "known" terminal morphologies.},
    url = "https://doi.org/10.1371/journal.pone.0007626",
    doi = "10.1371/journal.pone.0007626",
    openalex = "W2094698530",
    references = "doi10100210970177200099999999aiddvdy107330co2f, doi101002jmor10575, doi1010079781489953919, doi101007978148995740520, doi101029sc005p0175, doi101093sysbio24137, doi101111j109636421997tb00340x, doi101111j174966321940tb57047x, doi1016660094837320040300253chopom20co2, doi1016660094837320050310291teafot20co2, doi10167102724634200828134ooceit20co2, doi1023072532815, openalexw2259418280"
}

It has often been assumed that Australasian Cretaceous dinosaur faunas were for the most part endemic, but with some Laurasian affinities. In this regard, some Australasian dinosaurs have been considered Jurassic relicts, while others were thought to represent typical Laurasian forms or endemic taxa. Furthermore, it has been proposed that some dinosaurian lineages, namely oviraptorosaurians, dromaeosaurids, ornithomimosaurians and protoceratopsians, may have originated in Australia before dispersing to Asia during the Early Cretaceous. Here we provide a detailed review of Cretaceous non-avian dinosaurs from Australia and New Zealand, and compare them with taxa from other Gondwanan landmasses. Our results challenge the traditional view of Australian dinosaur faunas, with the majority of taxa displaying affinities that are concordant with current palaeobiogeographic models of Gondwanan terrestrial vertebrate faunal distribution. We reinterpret putative Australian ‘hypsilophodontids’ as basal ornithopods (some of them probably related to South American forms), and the recently described protoceratopsians are referred to Genasauria indet. and Ornithopoda indet. Among Theropoda, the Australian pigmy ‘Allosaurus’ is referred to the typical Gondwanan clade Abelisauroidea. Similarities are also observed between the enigmatic Australian theropod Rapator, Australovenator and the South American carcharodontosaurian Megaraptor. Timimus and putative oviraptorosaurians are referred to Dromaeosauridae. The present revision demonstrates that Australia's non-avian Cretaceous dinosaurian faunas were reminiscent of those found in other, roughly contemporaneous, Gondwanan landmasses, and are suggestive of faunal interchange with these regions via Antarctica.

@article{doi10108014772011003594870,
    author = "Agnolín, Federico L. and Ezcurra, Martín D. and Pais, Diego F. and Salisbury, Steven W.",
    title = "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities",
    year = "2010",
    journal = "Journal of Systematic Palaeontology",
    abstract = "It has often been assumed that Australasian Cretaceous dinosaur faunas were for the most part endemic, but with some Laurasian affinities. In this regard, some Australasian dinosaurs have been considered Jurassic relicts, while others were thought to represent typical Laurasian forms or endemic taxa. Furthermore, it has been proposed that some dinosaurian lineages, namely oviraptorosaurians, dromaeosaurids, ornithomimosaurians and protoceratopsians, may have originated in Australia before dispersing to Asia during the Early Cretaceous. Here we provide a detailed review of Cretaceous non-avian dinosaurs from Australia and New Zealand, and compare them with taxa from other Gondwanan landmasses. Our results challenge the traditional view of Australian dinosaur faunas, with the majority of taxa displaying affinities that are concordant with current palaeobiogeographic models of Gondwanan terrestrial vertebrate faunal distribution. We reinterpret putative Australian ‘hypsilophodontids’ as basal ornithopods (some of them probably related to South American forms), and the recently described protoceratopsians are referred to Genasauria indet. and Ornithopoda indet. Among Theropoda, the Australian pigmy ‘Allosaurus’ is referred to the typical Gondwanan clade Abelisauroidea. Similarities are also observed between the enigmatic Australian theropod Rapator, Australovenator and the South American carcharodontosaurian Megaraptor. Timimus and putative oviraptorosaurians are referred to Dromaeosauridae. The present revision demonstrates that Australia's non-avian Cretaceous dinosaurian faunas were reminiscent of those found in other, roughly contemporaneous, Gondwanan landmasses, and are suggestive of faunal interchange with these regions via Antarctica.",
    url = "https://doi.org/10.1080/14772011003594870",
    doi = "10.1080/14772011003594870",
    openalex = "W2151988812",
    references = "chinsamy1998polar, crossref1998encyclopedia, deklerk2000a, doi101017s0016756804000330, doi10108002724634198510011859, doi10108002724634199510011230, doi101093oxfordjournalsafrafa101747, doi101098rspb20060443, doi101126science10246376, doi101126science11282807, doi101126science24248841403, doi101126science28454232137, doi105281zenodo16171435, doi105281zenodo16673433, doi105281zenodo16692311, doi105860choice331556, doi105860choice353642, doi107312kiel11918, openalexw1821824396, openalexw1879660213, openalexw2173200745, openalexw597685939, openalexw616953834"
}

Hübner, Tom R., Rauhut, Oliver W. M. (2010): A juvenile skull of Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia), and implications for cranial ontogeny, phylogeny, and taxonomy in ornithopod dinosaurs. Zoological Journal of the Linnean Society 160 (2): 366-396, DOI: 10.1111/j.1096-3642.2010.00620.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2010.00620.x

@article{doi101111j10963642201000620x,
    author = "Hübner, Tom and Rauhut, Oliver W. M.",
    title = "A juvenile skull of Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia), and implications for cranial ontogeny, phylogeny, and taxonomy in ornithopod dinosaurs",
    year = "2010",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Hübner, Tom R., Rauhut, Oliver W. M. (2010): A juvenile skull of Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia), and implications for cranial ontogeny, phylogeny, and taxonomy in ornithopod dinosaurs. Zoological Journal of the Linnean Society 160 (2): 366-396, DOI: 10.1111/j.1096-3642.2010.00620.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2010.00620.x",
    url = "https://doi.org/10.1111/j.1096-3642.2010.00620.x",
    doi = "10.1111/j.1096-3642.2010.00620.x",
    openalex = "W1958669515",
    references = "crossref1998encyclopedia, doi1010029780470750711, doi101017s1477201907002271, doi101093aesa254757, doi1015468gcrned, doi10210802890003200421105ansmsc20co2, doi1023072532815, doi102307jctvxkn7tk, doi105860choice393984, doi105962p313819, openalexw2183707334, openalexw225597919"
}

BACKGROUND: A dinosaur census recorded during the Hell Creek Project (1999-2009) incorporates multiple lines of evidence from geography, taphohistory, stratigraphy, phylogeny and ontogeny to investigate the relative abundance of large dinosaurs preserved in the Upper Cretaceous Hell Creek Formation of northeastern Montana, USA. Overall, the dinosaur skeletal assemblages in the Hell Creek Formation (excluding lag-influenced records) consist primarily of subadult or small adult size individuals. Small juveniles and large adults are both extremely rare, whereas subadult individuals are relatively common. We propose that mature individuals of at least some dinosaur taxa either lived in a separate geographic locale analogous to younger individuals inhabiting an upland environment where sedimentation rates were relatively less, or these taxa experienced high mortality before reaching terminal size where late stage and often extreme cranial morphology is expressed. METHODOLOGY/PRINCIPAL FINDINGS: Tyrannosaurus skeletons are as abundant as Edmontosaurus, an herbivore, in the upper Hell Creek Formation and nearly twice as common in the lower third of the formation. Smaller, predatory dinosaurs (e.g., Troodon and dromaeosaurids) are primarily represented by teeth found in microvertebrate localities and their skeletons or identifiable lag specimens were conspicuously absent. This relative abundance suggests Tyrannosaurus was not a typical predator and likely benefited from much wider food choice opportunities than exclusively live prey and/or specific taxa. Tyrannosaurus adults may not have competed with Tyrannosaurus juveniles if the potential for selecting carrion increased with size during ontogeny. CONCLUSIONS/SIGNIFICANCE: Triceratops is the most common dinosaur and isolated skulls contribute to a significant portion of this census. Associated specimens of Triceratops consisting of both cranial and postcranial elements remain relatively rare. This rarity may be explained by a historical collecting bias influenced by facies and taphonomic factors. The limited discovery of postcranial elements may also depend on how extensive a fossil quarry is expanded after a skull is collected.

@article{doi101371journalpone0016574,
    author = "Horner, John R. and Goodwin, Mark B. and Myhrvold, Nathan",
    title = "Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA",
    year = "2011",
    journal = "PLoS ONE",
    abstract = "BACKGROUND: A dinosaur census recorded during the Hell Creek Project (1999-2009) incorporates multiple lines of evidence from geography, taphohistory, stratigraphy, phylogeny and ontogeny to investigate the relative abundance of large dinosaurs preserved in the Upper Cretaceous Hell Creek Formation of northeastern Montana, USA. Overall, the dinosaur skeletal assemblages in the Hell Creek Formation (excluding lag-influenced records) consist primarily of subadult or small adult size individuals. Small juveniles and large adults are both extremely rare, whereas subadult individuals are relatively common. We propose that mature individuals of at least some dinosaur taxa either lived in a separate geographic locale analogous to younger individuals inhabiting an upland environment where sedimentation rates were relatively less, or these taxa experienced high mortality before reaching terminal size where late stage and often extreme cranial morphology is expressed. METHODOLOGY/PRINCIPAL FINDINGS: Tyrannosaurus skeletons are as abundant as Edmontosaurus, an herbivore, in the upper Hell Creek Formation and nearly twice as common in the lower third of the formation. Smaller, predatory dinosaurs (e.g., Troodon and dromaeosaurids) are primarily represented by teeth found in microvertebrate localities and their skeletons or identifiable lag specimens were conspicuously absent. This relative abundance suggests Tyrannosaurus was not a typical predator and likely benefited from much wider food choice opportunities than exclusively live prey and/or specific taxa. Tyrannosaurus adults may not have competed with Tyrannosaurus juveniles if the potential for selecting carrion increased with size during ontogeny. CONCLUSIONS/SIGNIFICANCE: Triceratops is the most common dinosaur and isolated skulls contribute to a significant portion of this census. Associated specimens of Triceratops consisting of both cranial and postcranial elements remain relatively rare. This rarity may be explained by a historical collecting bias influenced by facies and taphonomic factors. The limited discovery of postcranial elements may also depend on how extensive a fossil quarry is expanded after a skull is collected.",
    url = "https://doi.org/10.1371/journal.pone.0016574",
    doi = "10.1371/journal.pone.0016574",
    openalex = "W1982210430",
    references = "carr1999craniofacial, doi101038282296a0, doi101073pnas0708903105, doi101080027246342010483632, doi101098rspb20042829, doi101371journalpone0007626, doi1016660094837320010270039coosea20co2, doi1016710272463420000200115lbhoth20co2, doi1023072404970, openalexw1550433756"
}

The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.

@article{doi101371journalpone0021376,
    author = "Fowler, Denver W. and Woodward, Holly N. and Freedman, Elizabeth A. and Larson, Peter L. and Horner, John R.",
    title = "Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia",
    year = "2011",
    journal = "PLoS ONE",
    abstract = "The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.",
    url = "https://doi.org/10.1371/journal.pone.0021376",
    doi = "10.1371/journal.pone.0021376",
    openalex = "W2031566253",
    references = "carr1999craniofacial, doi1010079781489953919, doi101029sc005p0175, doi10103835086500, doi101038nature02699, doi10108002724634199610011283, doi10108002724634200310010947, doi1016710272463420000200115lbhoth20co2, doi1023073889334, doi105860choice393984"
}

Recent discoveries in Asia have greatly increased our understanding of the evolution of dinosaurs' integumentary structures, revealing a previously unexpected diversity of "protofeathers" and feathers. However, all theropod dinosaurs with preserved feathers reported so far are coelurosaurs. Evidence for filaments or feathers in noncoelurosaurian theropods is circumstantial and debated. Here we report an exceptionally preserved skeleton of a juvenile megalosauroid, Sciurumimus albersdoerferi n. gen., n. sp., from the Late Jurassic of Germany, which preserves a filamentous plumage at the tail base and on parts of the body. These structures are identical to the type 1 feathers that have been reported in some ornithischians, the basal tyrannosaur Dilong, the basal therizinosauroid Beipiaosaurus, and, probably, in the basal coelurosaur Sinosauropteryx. Sciurumimus albersdoerferi represents the phylogenetically most basal theropod that preserves direct evidence for feathers and helps close the gap between feathers reported in coelurosaurian theropods and filaments in ornithischian dinosaurs, further supporting the homology of these structures. The specimen of Sciurumimus is the most complete megalosauroid yet discovered and helps clarify significant anatomical details of this important basal theropod clade, such as the complete absence of the fourth digit of the manus. The dentition of this probably early-posthatchling individual is markedly similar to that of basal coelurosaurian theropods, indicating that coelurosaur occurrences based on isolated teeth should be used with caution.

@article{doi101073pnas1203238109,
    author = "Rauhut, Oliver W. M. and Foth, Christian and Tischlinger, Helmut and Norell, Mark A.",
    title = "Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany",
    year = "2012",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Recent discoveries in Asia have greatly increased our understanding of the evolution of dinosaurs' integumentary structures, revealing a previously unexpected diversity of "protofeathers" and feathers. However, all theropod dinosaurs with preserved feathers reported so far are coelurosaurs. Evidence for filaments or feathers in noncoelurosaurian theropods is circumstantial and debated. Here we report an exceptionally preserved skeleton of a juvenile megalosauroid, Sciurumimus albersdoerferi n. gen., n. sp., from the Late Jurassic of Germany, which preserves a filamentous plumage at the tail base and on parts of the body. These structures are identical to the type 1 feathers that have been reported in some ornithischians, the basal tyrannosaur Dilong, the basal therizinosauroid Beipiaosaurus, and, probably, in the basal coelurosaur Sinosauropteryx. Sciurumimus albersdoerferi represents the phylogenetically most basal theropod that preserves direct evidence for feathers and helps close the gap between feathers reported in coelurosaurian theropods and filaments in ornithischian dinosaurs, further supporting the homology of these structures. The specimen of Sciurumimus is the most complete megalosauroid yet discovered and helps clarify significant anatomical details of this important basal theropod clade, such as the complete absence of the fourth digit of the manus. The dentition of this probably early-posthatchling individual is markedly similar to that of basal coelurosaurian theropods, indicating that coelurosaur occurrences based on isolated teeth should be used with caution.},
    url = "https://doi.org/10.1073/pnas.1203238109",
    doi = "10.1073/pnas.1203238109",
    openalex = "W2033273405",
    references = "benson2008a, carr1999craniofacial, crossref2013dinosaurs, doi101002jmor10382, doi101002sici1097010x199912152854291aidjez130co29, doi101007s001140090614x, doi101016jearscirev201004001, doi10103832884, doi101038nature02699, doi101038nature04511, doi101038nature07856, doi10108002724634199610011283, doi10108002724634199910011161, doi101111j10963642200600232x, doi101111j10963642200900569x, doi1011270077774920100125, doi101139e93179, doi10120600030082200635451andtfu20co2, doi1023072424244, doi105479si03629236110i"
}

BACKGROUND: Rhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island. METHODOLOGY/PRINCIPAL FINDINGS: Rhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6-1.8 m in the Hungarian and Austrian species, 2.4-2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5-6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320-333 mm). CONCLUSIONS/SIGNIFICANCE: Our analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre-Santonian divergence between western and eastern rhabdodontid lineages within the western Tethyan archipelago.

@article{doi101371journalpone0044318,
    author = "Ősi, Attila and Prondvai, Edina and Butler, Richard J. and Weishampel, David B.",
    title = "Phylogeny, Histology and Inferred Body Size Evolution in a New Rhabdodontid Dinosaur from the Late Cretaceous of Hungary",
    year = "2012",
    journal = "PLoS ONE",
    abstract = "BACKGROUND: Rhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island. METHODOLOGY/PRINCIPAL FINDINGS: Rhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6-1.8 m in the Hungarian and Austrian species, 2.4-2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5-6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320-333 mm). CONCLUSIONS/SIGNIFICANCE: Our analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre-Santonian divergence between western and eastern rhabdodontid lineages within the western Tethyan archipelago.",
    url = "https://doi.org/10.1371/journal.pone.0044318",
    doi = "10.1371/journal.pone.0044318",
    openalex = "W2004173110",
    references = "doi101002jmor10524, doi101007978140206754912413, doi101016s1631068303000022, doi101080027246342012694385, doi101098rspl18870117, doi101111j10960031200800209x, doi101111j1469185x201000137x, doi101371journalpbio0040321, doi101371journalpone0029958, doi102307jctt1zxz1md6, doi102475ajss31695411, doi102475ajss319111253, doi105281zenodo16673433, doi105860choice393984, doi105860choice503272, doi105962p313819, openalexw225597919"
}

Abstract The global Late Maastrichtian non-avian dinosaur apparent biodiversity is extensively surveyed for the first time. It amounts to 104 species (including unnamed forms) in 2010. The real biodiversity being obscured by taphonomical biases and the scarcity of the continental fossil record, a species-area relationship is used to estimate it. The results show that several hundreds (between 628 and 1078) non-avian dinosaur species were alive in the Late Maastrichtian, which is almost an order of magnitude above previous estimates. Because of the complex Late Cretaceous palaeobiogeography, discussions about dinosaur extinction should be based on this estimated real global biodiversity, not on the apparent biodiversity of a single area. Given the mean duration of dinosaur genera (7.7 Ma), the presence of so many dinosaur species in the Latest Cretaceous is consistent with the termination of most lineages at the Cretaceous-Tertiary boundary (the Late Maastrichtian sub-stage is 2.8 m.y. long). The Late Maastrichtian dinosaurian biodiversity is therefore consistent with the sudden extinction of the group following the Chicxulub impact.

@article{doi102113gssgfbull1836547,
    author = "Lœuff, Jean Le",
    title = "Paleobiogeography and biodiversity of Late Maastrichtian dinosaurs: how many dinosaur species went extinct at the Cretaceous-Tertiary boundary?",
    year = "2012",
    journal = "Bulletin de la Société Géologique de France",
    abstract = "Abstract The global Late Maastrichtian non-avian dinosaur apparent biodiversity is extensively surveyed for the first time. It amounts to 104 species (including unnamed forms) in 2010. The real biodiversity being obscured by taphonomical biases and the scarcity of the continental fossil record, a species-area relationship is used to estimate it. The results show that several hundreds (between 628 and 1078) non-avian dinosaur species were alive in the Late Maastrichtian, which is almost an order of magnitude above previous estimates. Because of the complex Late Cretaceous palaeobiogeography, discussions about dinosaur extinction should be based on this estimated real global biodiversity, not on the apparent biodiversity of a single area. Given the mean duration of dinosaur genera (7.7 Ma), the presence of so many dinosaur species in the Latest Cretaceous is consistent with the termination of most lineages at the Cretaceous-Tertiary boundary (the Late Maastrichtian sub-stage is 2.8 m.y. long). The Late Maastrichtian dinosaurian biodiversity is therefore consistent with the sudden extinction of the group following the Chicxulub impact.",
    url = "https://doi.org/10.2113/gssgfbull.183.6.547",
    doi = "10.2113/gssgfbull.183.6.547",
    openalex = "W2129835365",
    references = "doi101086379695"
}

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"
}

The Late Cretaceous (∼95-66 million years ago) western North American landmass of Laramidia displayed heightened non-marine vertebrate diversity and intracontinental regionalism relative to other latest Cretaceous Laurasian ecosystems. Processes generating these patterns during this interval remain poorly understood despite their presumed role in the diversification of many clades. Tyrannosauridae, a clade of large-bodied theropod dinosaurs restricted to the Late Cretaceous of Laramidia and Asia, represents an ideal group for investigating Laramidian patterns of evolution. We use new tyrannosaurid discoveries from Utah--including a new taxon which represents the geologically oldest member of the clade--to investigate the evolution and biogeography of Tyrannosauridae. These data suggest a Laramidian origin for Tyrannosauridae, and implicate sea-level related controls in the isolation, diversification, and dispersal of this and many other Late Cretaceous vertebrate clades.

@article{doi101371journalpone0079420,
    author = "Loewen, Mark A. and Irmis, Randall B. and Sertich, Joseph J. W. and Currie, Philip J. and Sampson, Scott D.",
    title = "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans",
    year = "2013",
    journal = "PLoS ONE",
    abstract = "The Late Cretaceous (∼95-66 million years ago) western North American landmass of Laramidia displayed heightened non-marine vertebrate diversity and intracontinental regionalism relative to other latest Cretaceous Laurasian ecosystems. Processes generating these patterns during this interval remain poorly understood despite their presumed role in the diversification of many clades. Tyrannosauridae, a clade of large-bodied theropod dinosaurs restricted to the Late Cretaceous of Laramidia and Asia, represents an ideal group for investigating Laramidian patterns of evolution. We use new tyrannosaurid discoveries from Utah--including a new taxon which represents the geologically oldest member of the clade--to investigate the evolution and biogeography of Tyrannosauridae. These data suggest a Laramidian origin for Tyrannosauridae, and implicate sea-level related controls in the isolation, diversification, and dispersal of this and many other Late Cretaceous vertebrate clades.",
    url = "https://doi.org/10.1371/journal.pone.0079420",
    doi = "10.1371/journal.pone.0079420",
    openalex = "W2091933212",
    references = "doi101080027246342011557116, doi10108010635150701883881, doi101111j10960031200800217x, doi101111j10963642200900591x, doi101111j155856461985tb00420x, doi101126science1116412, doi101126science23547931156, doi101214aos1176344552, doi101371journalpone0021376, doi1015259780520941434, doi1023072408678, doi102475ajss321125417, doi105281zenodo16171435, nesbitt2009a, openalexw2611511275, openalexw3215057009"
}

@article{doi101016jcretres201405003,
    author = "Prieto-Márquez, A.",
    title = "A juvenile Edmontosaurus from the late Maastrichtian (Cretaceous) of North America: Implications for ontogeny and phylogenetic inference in saurolophine dinosaurs",
    year = "2014",
    journal = "Cretaceous Research",
    url = "https://www.semanticscholar.org/paper/0ad151c49e4af951a80503d6600a06414abf1d4c",
    doi = "10.1016/J.CRETRES.2014.05.003",
    is_oa = "true",
    pages = "282-303",
    semanticscholar_citation_count = "48",
    semanticscholar_id = "0ad151c49e4af951a80503d6600a06414abf1d4c",
    volume = "50"
}

The Cretaceous-Paleogene boundary marks a critical event in mammalian evolution. Using a database of 4769 mammalian specimens from the Hell Creek and lower Fort Union formations of Garfield County, northeastern Montana, I quantified temporal patterns of diversity and community structure to evaluate faunal dynamics during the last ~1.9 m.y. of the Cretaceous, the Cretaceous-Paleogene extinction and survival, and the first ~1.2 m.y. of the early Paleocene recovery and placental radiation.

@incollection{doi1011302014250315,
    author = "Wilson, Gregory P.",
    title = "Mammalian extinction, survival, and recovery dynamics across the Cretaceous-Paleogene boundary in northeastern Montana, USA",
    year = "2014",
    booktitle = "Geological Society of America eBooks",
    abstract = "The Cretaceous-Paleogene boundary marks a critical event in mammalian evolution. Using a database of 4769 mammalian specimens from the Hell Creek and lower Fort Union formations of Garfield County, northeastern Montana, I quantified temporal patterns of diversity and community structure to evaluate faunal dynamics during the last \textasciitilde 1.9 m.y. of the Cretaceous, the Cretaceous-Paleogene extinction and survival, and the first \textasciitilde 1.2 m.y. of the early Paleocene recovery and placental radiation.",
    url = "https://doi.org/10.1130/2014.2503(15)",
    doi = "10.1130/2014.2503(15)",
    openalex = "W2500553572",
    references = "archibald1982upper, doi101038nature05634, doi101046j14724642199900046x, doi101111j14610248200701094x, doi101126science1177265, doi10113000917613198210153ucbamh20co2, doi101130spe190p291, doi1016660094837320002674oaecot20co2, doi1016660094837336180, doi10166612041, doi105860choice421547, doi107312kiel11918, hotton2002palynology, openalexw1530215206, openalexw2183707334, openalexw610180004"
}

Detailed understanding of ecosystem decline and recovery attending the Cretaceous-Paleogene boundary (KPB) mass extinctions is hindered by limited constraints on the pace and tempo of environmental events near the boundary. To mitigate this shortcoming, high-resolution 40Ar/39Ar geochronology was performed on tephras intercalated between fossiliferous terrestrial sediments of the upper Hell Creek and lower Fort Union Formations in the western Williston Basin of northeastern Montana (USA). Tephra samples were collected from 10 stratigraphic sections spanning an area of ~5000 km2. Several distinctive tephras can be correlated between sections separated spatially by as much as ~60 km. The tephras are thin distal deposits generally preserved only in lignite beds, which are interbedded with clastic deposits yielding vertebrate faunas of Lancian (late Maastrichtian) to Torrejonian (early Danian) North American Land Mammal Ages. Sanidine from 15 tephra samples was analyzed in 1649 total fusion experiments (1597 on single crystals) and 12 incremental heating analyses of multigrain aliquots. Ages were determined for 13 distinct tephras, ranging from 66.289 ± 0.051 to 64.866 ± 0.023 Ma, including only analytical uncertainties. This level of precision is sufficient to resolve the ages of all of the coal beds that have served as a basis for a regional stratigraphic framework. The data confirm that the Hell Creek-Fort Union formational contact is diachronous, and further support the age of the KPB impact layer at 66.043 ± 0.010 Ma (or ± 0.043 Ma considering systematic uncertainties). Application of the new results to previous magnetostratigraphic data indicates an appreciably compressed time interval between the base of chron C29r and the top of chron C28r, with a maximum duration estimate of 1.421 ± 0.066 Ma. Most notable is the implied brevity of chron C29r, with a maximum estimate of 457 ± 54 ka, and possibly as brief as 345 ± 38 ka, compared to the 710 ka estimate from the Geologic Time Scale 2012 (GTS2012). Further, application of new results to terrestrial biostratigraphy adds higher precision to the timing and tempo of biotic change before and after the KPB. Our results indicate that the timing of pre-KPB ecological decline is constrained to the last ~200 ka of the Cretaceous, adding further support to the press-pulse extinction hypothesis. Additionally, the duration of the depauperate basal Paleogene Puercan 1 disas ter fauna is confined to a 70 ka interval. Faunal recovery in this region, indicated by the appearance of primitive members of the placental mammal radiation and the restoration of taxonomic richness and evenness, occurred within ~900 ka after the KPB. These results show that biotic recovery after the mass extinction in the terrestrial realm was more rapid than in the marine.

@article{doi101130b310761,
    author = "Sprain, Courtney J. and Renne, Paul R. and Wilson, Gregory P. and Clemens, W. A.",
    title = "High-resolution chronostratigraphy of the terrestrial Cretaceous-Paleogene transition and recovery interval in the Hell Creek region, Montana",
    year = "2014",
    journal = "Geological Society of America Bulletin",
    abstract = "Detailed understanding of ecosystem decline and recovery attending the Cretaceous-Paleogene boundary (KPB) mass extinctions is hindered by limited constraints on the pace and tempo of environmental events near the boundary. To mitigate this shortcoming, high-resolution 40Ar/39Ar geochronology was performed on tephras intercalated between fossiliferous terrestrial sediments of the upper Hell Creek and lower Fort Union Formations in the western Williston Basin of northeastern Montana (USA). Tephra samples were collected from 10 stratigraphic sections spanning an area of \textasciitilde 5000 km2. Several distinctive tephras can be correlated between sections separated spatially by as much as \textasciitilde 60 km. The tephras are thin distal deposits generally preserved only in lignite beds, which are interbedded with clastic deposits yielding vertebrate faunas of Lancian (late Maastrichtian) to Torrejonian (early Danian) North American Land Mammal Ages. Sanidine from 15 tephra samples was analyzed in 1649 total fusion experiments (1597 on single crystals) and 12 incremental heating analyses of multigrain aliquots. Ages were determined for 13 distinct tephras, ranging from 66.289 ± 0.051 to 64.866 ± 0.023 Ma, including only analytical uncertainties. This level of precision is sufficient to resolve the ages of all of the coal beds that have served as a basis for a regional stratigraphic framework. The data confirm that the Hell Creek-Fort Union formational contact is diachronous, and further support the age of the KPB impact layer at 66.043 ± 0.010 Ma (or ± 0.043 Ma considering systematic uncertainties). Application of the new results to previous magnetostratigraphic data indicates an appreciably compressed time interval between the base of chron C29r and the top of chron C28r, with a maximum duration estimate of 1.421 ± 0.066 Ma. Most notable is the implied brevity of chron C29r, with a maximum estimate of 457 ± 54 ka, and possibly as brief as 345 ± 38 ka, compared to the 710 ka estimate from the Geologic Time Scale 2012 (GTS2012). Further, application of new results to terrestrial biostratigraphy adds higher precision to the timing and tempo of biotic change before and after the KPB. Our results indicate that the timing of pre-KPB ecological decline is constrained to the last \textasciitilde 200 ka of the Cretaceous, adding further support to the press-pulse extinction hypothesis. Additionally, the duration of the depauperate basal Paleogene Puercan 1 disas ter fauna is confined to a 70 ka interval. Faunal recovery in this region, indicated by the appearance of primitive members of the placental mammal radiation and the restoration of taxonomic richness and evenness, occurred within \textasciitilde 900 ka after the KPB. These results show that biotic recovery after the mass extinction in the terrestrial realm was more rapid than in the marine.",
    url = "https://doi.org/10.1130/b31076.1",
    doi = "10.1130/b31076.1",
    openalex = "W2044128051",
    references = "alvarez1980extraterrestrial, archibald1982upper, doi101016jepsl200707011, doi101016jgca201106021, doi101016jpalaeo200709016, doi1010292008jb005644, doi101073pnas0234701100, doi101073pnas802627, doi101126science1154339, doi101126science1177265, doi101126science1230492, doi101126science1483667220, doi101126science22346411177, doi10113000917613198210153ucbamh20co2, doi10113000917613198614279ssaedt20co2, doi101146annurevecolsys35021103105715, doi10166612041, doi1023073514678, openalexw610180004, rigby1987dinosaurs"
}

@article{doi101016jcretres201409006,
    author = "Bell, P. and Currie, P. and Russell, D.",
    title = "Large caenagnathids (Dinosauria, Oviraptorosauria) from the uppermost Cretaceous of western Canada",
    year = "2015",
    journal = "Cretaceous Research",
    url = "https://www.semanticscholar.org/paper/2ef555f111b8645df7ca43516a33a8eee61da7c9",
    doi = "10.1016/J.CRETRES.2014.09.006",
    is_oa = "true",
    pages = "101-107",
    semanticscholar_citation_count = "22",
    semanticscholar_id = "2ef555f111b8645df7ca43516a33a8eee61da7c9",
    volume = "52"
}

Rare earth element (REE) analysis of vertebrate fossils has previously been used to answer a number of stratigraphic, taphonomic, and paleoenvironmental questions concerning the depositional environments of Cretaceous siliciclastic marine and freshwater formations. In this study, vertebrate fossils from Upper Cretaceous formations of Alabama were analyzed to determine if REE analyses could be equally effective at resolving taphonomic and paleoenvironmental questions in marine carbonate strata. Results indicate that these fossils possess unique REE signatures, although they are not as distinctive as those of siliciclastic formations. REE data can also be used, with limitations, for stratigraphic assignment of vertebrate fossils as well as indicating relative paleobathymetry. Furthermore, differences in REE signatures between certain taxonomic groups and REE concentrations in different osteological material are observed. In conclusion, findings herein indicate that REE analysis of vertebrate fossils from carbonate deposits can be effective for paleoenvironmental and regional paleogeographic studies.

@article{doi102110palo2014031,
    author = "Harrell, T. Lynn and Pérez‐Huerta, Alberto",
    title = "RARE EARTH ELEMENT (REE) ANALYSIS OF VERTEBRATE FOSSILS FROM THE UPPER CRETACEOUS CARBONATE MARINE FORMATIONS OF WESTERN AND CENTRAL ALABAMA, USA: TAPHONOMIC AND PALEOENVIRONMENTAL IMPLICATIONS",
    year = "2015",
    journal = "Palaios",
    abstract = "Rare earth element (REE) analysis of vertebrate fossils has previously been used to answer a number of stratigraphic, taphonomic, and paleoenvironmental questions concerning the depositional environments of Cretaceous siliciclastic marine and freshwater formations. In this study, vertebrate fossils from Upper Cretaceous formations of Alabama were analyzed to determine if REE analyses could be equally effective at resolving taphonomic and paleoenvironmental questions in marine carbonate strata. Results indicate that these fossils possess unique REE signatures, although they are not as distinctive as those of siliciclastic formations. REE data can also be used, with limitations, for stratigraphic assignment of vertebrate fossils as well as indicating relative paleobathymetry. Furthermore, differences in REE signatures between certain taxonomic groups and REE concentrations in different osteological material are observed. In conclusion, findings herein indicate that REE analysis of vertebrate fossils from carbonate deposits can be effective for paleoenvironmental and regional paleogeographic studies.",
    url = "https://doi.org/10.2110/palo.2014.031",
    doi = "10.2110/palo.2014.031",
    openalex = "W2177636454",
    references = "doi101016jgca2006061556"
}

Australian dinosaurs have played a rare but controversial role in the debate surrounding the effect of Gondwanan break-up on Cretaceous dinosaur distribution. Major spatiotemporal gaps in the Gondwanan Cretaceous fossil record, coupled with taxon incompleteness, have hindered research on this effect, especially in Australia. Here we report on two new sauropod specimens from the early Late Cretaceous of Queensland, Australia, that have important implications for Cretaceous dinosaur palaeobiogeography. Savannasaurus elliottorum gen. et sp. nov. comprises one of the most complete Cretaceous sauropod skeletons ever found in Australia, whereas a new specimen of Diamantinasaurus matildae includes the first ever cranial remains of an Australian sauropod. The results of a new phylogenetic analysis, in which both Savannasaurus and Diamantinasaurus are recovered within Titanosauria, were used as the basis for a quantitative palaeobiogeographical analysis of macronarian sauropods. Titanosaurs achieved a worldwide distribution by at least 125 million years ago, suggesting that mid-Cretaceous Australian sauropods represent remnants of clades which were widespread during the Early Cretaceous. These lineages would have entered Australasia via dispersal from South America, presumably across Antarctica. High latitude sauropod dispersal might have been facilitated by Albian-Turonian warming that lifted a palaeoclimatic dispersal barrier between Antarctica and South America.

@article{doi101038srep34467,
    author = "Poropat, Stephen F. and Mannion, Philip D. and Upchurch, Paul and Hocknull, Scott and Kear, Benjamin P. and Kundrát, Martin and Tischler, Travis R. and Sloan, Trish and Sinapius, George H. K. and Elliott, Judy A. and Elliott, David A.",
    title = "New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography",
    year = "2016",
    journal = "Scientific Reports",
    abstract = "Australian dinosaurs have played a rare but controversial role in the debate surrounding the effect of Gondwanan break-up on Cretaceous dinosaur distribution. Major spatiotemporal gaps in the Gondwanan Cretaceous fossil record, coupled with taxon incompleteness, have hindered research on this effect, especially in Australia. Here we report on two new sauropod specimens from the early Late Cretaceous of Queensland, Australia, that have important implications for Cretaceous dinosaur palaeobiogeography. Savannasaurus elliottorum gen. et sp. nov. comprises one of the most complete Cretaceous sauropod skeletons ever found in Australia, whereas a new specimen of Diamantinasaurus matildae includes the first ever cranial remains of an Australian sauropod. The results of a new phylogenetic analysis, in which both Savannasaurus and Diamantinasaurus are recovered within Titanosauria, were used as the basis for a quantitative palaeobiogeographical analysis of macronarian sauropods. Titanosaurs achieved a worldwide distribution by at least 125 million years ago, suggesting that mid-Cretaceous Australian sauropods represent remnants of clades which were widespread during the Early Cretaceous. These lineages would have entered Australasia via dispersal from South America, presumably across Antarctica. High latitude sauropod dispersal might have been facilitated by Albian-Turonian warming that lifted a palaeoclimatic dispersal barrier between Antarctica and South America.",
    url = "https://doi.org/10.1038/srep34467",
    doi = "10.1038/srep34467",
    openalex = "W2535200874",
    references = "doi101016jcretres201304001, doi101016jearscirev201203002, doi101016jgr201212009, doi101016jgr201403014, doi101038srep19165, doi101046j10963642200200029x, doi10108014772011003594870, doi1010801477201920151059985, doi101111j10960031200800217x, doi101111j109636421998tb00569x, doi101111zoj12029, doi101126science1116412, doi101126science2725264986, doi1011300016760619951071164mlccot23co2, doi101371journalpone0006190, doi101371journalpone0037122, doi101371journalpone0125819, doi1015259780520941434, doi1021425f55419694, doi1021425f5fbg19694, doi105194cp813232012, doi107717peerj1523, openalexw2173200745"
}

@inproceedings{andweaver2017authigenic,
    author = "Weaver, Lucas N. and Rogers, Raymond R. and Thole, Jeffrey T.",
    title = "AUTHIGENIC MINERALOGY AND ELEMENT DISTRIBUTIONS OF VERTEBRATE MICROFOSSILS FROM THE HELL CREEK (LATEST CRETACEOUS) AND TULLOCK (PALEOCENE) FORMATIONS OF EASTERN MONTANA",
    year = "2017",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2017am-301737",
    doi = "10.1130/abs/2017am-301737",
    openalex = "W2775302964"
}

@article{doi1010800272463420171398168,
    author = "Wosik, Mateusz and Goodwin, M. and Evans, D. C.",
    title = "A Nestling-Sized Skeleton of Edmontosaurus (Ornithischia, Hadrosauridae) from the Hell Creek Formation of Northeastern Montana, U.S.A., With an Analysis of Ontogenetic Limb Allometry",
    year = "2017",
    journal = "Journal of Vertebrate Paleontology",
    url = "https://www.semanticscholar.org/paper/a405e6675d76d12fea01110b683e94c716b28912",
    doi = "10.1080/02724634.2017.1398168",
    is_oa = "true",
    number = "6",
    pages = "e1398168",
    semanticscholar_citation_count = "24",
    semanticscholar_id = "a405e6675d76d12fea01110b683e94c716b28912",
    volume = "37"
}

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 mass extinction at the Cretaceous- Paleogene boundary marks one of the most important biotic turnover events in Earth history. Yet, despite decades of study, the causes of the Cretaceous-Paleogene boundary crises remain under debate. An important tool that has the capacity to greatly improve our understanding of the events around the Cretaceous-Paleogene boundary is the geomagnetic polarity time scale (GPTS). The GPTS is used for age control in numerous Cretaceous-Paleogene boundary studies, including the timing of Deccan Traps volcanism, a majority of studies in marine sections, and studies on climate and ecological change across the Cretaceous-Paleogene boundary. The current calibration of the GPTS for circum- Cretaceous-Paleogene boundary polarity chrons (C30n-C28n) from the Geologic Time Scale draws heavily on astronomical tuning and uses a 40Ar/39Ar age for the Cretaceous- Paleogene boundary as a tie point that has since been shown to be 200 ka too old. Furthermore, complex sedimentation has been recorded in marine sections immediately following the Cretaceous-Paleogene boundary, which can possibly obscure orbital signals and complicate cyclostratigraphic interpretation. An independent test of the cyclostratigraphy for this time period is imperative for confidence in the astronomical time scale. Further, polarity reversal ages given in the GPTS do not include uncertainty estimates, making them unsuitable for quantitative chronometry. Recent calibrations have been attempted using U/Pb geochronology on zircons; however, U/Pb zircon dates may be biased by pre-eruptive zircon residence times of tens to hundreds of thousands of years. In this study, we provide constraints on the timing and duration of the most important circum-Cretaceous-Paleogene boundary chron, chron C29r, using high-precision 40Ar/39Ar geochronology and magnetostratigraphy on fluvial sediments from the Hell Creek region, Montana. Here, we show results for 14 new magnetostratigraphic sections, and 18 new high-precision 40Ar/39Ar dates, which together provide six independent constraints on the age of the C29r/C29n reversal and two constraints on the C30n/ C29r reversal. Together, these results show that the duration of C29r was 587 ± 53 ka, consistent with the most recent Geologic Time Scale calibration and previous U-Pb age models. We further present new geochronologic data for the Cretaceous-Paleogene boundary that provide the most precise date yet, of 66.052 ± 0.008/0.043 Ma. Integration of our results into the extensive paleontological framework for this region further provides important constraints on rates of terrestrial faunal change across the Cretaceous-Paleogene boundary.

@article{doi101130b318901,
    author = "Sprain, Courtney J. and Renne, Paul R. and Clemens, William A. and Wilson, Gregory P.",
    title = "Calibration of chron C29r: New high-precision geochronologic and paleomagnetic constraints from the Hell Creek region, Montana",
    year = "2018",
    journal = "Geological Society of America Bulletin",
    abstract = "The mass extinction at the Cretaceous- Paleogene boundary marks one of the most important biotic turnover events in Earth history. Yet, despite decades of study, the causes of the Cretaceous-Paleogene boundary crises remain under debate. An important tool that has the capacity to greatly improve our understanding of the events around the Cretaceous-Paleogene boundary is the geomagnetic polarity time scale (GPTS). The GPTS is used for age control in numerous Cretaceous-Paleogene boundary studies, including the timing of Deccan Traps volcanism, a majority of studies in marine sections, and studies on climate and ecological change across the Cretaceous-Paleogene boundary. The current calibration of the GPTS for circum- Cretaceous-Paleogene boundary polarity chrons (C30n-C28n) from the Geologic Time Scale draws heavily on astronomical tuning and uses a 40Ar/39Ar age for the Cretaceous- Paleogene boundary as a tie point that has since been shown to be 200 ka too old. Furthermore, complex sedimentation has been recorded in marine sections immediately following the Cretaceous-Paleogene boundary, which can possibly obscure orbital signals and complicate cyclostratigraphic interpretation. An independent test of the cyclostratigraphy for this time period is imperative for confidence in the astronomical time scale. Further, polarity reversal ages given in the GPTS do not include uncertainty estimates, making them unsuitable for quantitative chronometry. Recent calibrations have been attempted using U/Pb geochronology on zircons; however, U/Pb zircon dates may be biased by pre-eruptive zircon residence times of tens to hundreds of thousands of years. In this study, we provide constraints on the timing and duration of the most important circum-Cretaceous-Paleogene boundary chron, chron C29r, using high-precision 40Ar/39Ar geochronology and magnetostratigraphy on fluvial sediments from the Hell Creek region, Montana. Here, we show results for 14 new magnetostratigraphic sections, and 18 new high-precision 40Ar/39Ar dates, which together provide six independent constraints on the age of the C29r/C29n reversal and two constraints on the C30n/ C29r reversal. Together, these results show that the duration of C29r was 587 ± 53 ka, consistent with the most recent Geologic Time Scale calibration and previous U-Pb age models. We further present new geochronologic data for the Cretaceous-Paleogene boundary that provide the most precise date yet, of 66.052 ± 0.008/0.043 Ma. Integration of our results into the extensive paleontological framework for this region further provides important constraints on rates of terrestrial faunal change across the Cretaceous-Paleogene boundary.",
    url = "https://doi.org/10.1130/b31890.1",
    doi = "10.1130/b31890.1",
    openalex = "W2802628992",
    references = "archibald1982upper, doi101007s1091400569434, doi101016003192017790108x, doi101016jepsl200801015, doi101016s0009254197001599, doi101016s0012821x03005570, doi101017cbo9780511536045, doi10102994jb03098, doi1010510004636120041335, doi101098rspa19530064, doi101111j1365246x1980tb02601x, doi101111j1365246x1990tb05683x, doi101111sed12405, doi101126science1154339, doi101126science1177265, doi10113000917613198210153ucbamh20co2, doi10113000917613198614279ssaedt20co2, doi101130b310761, doi1023073514678, doi103133pp776"
}

Perinatal specimens of hadrosaurids discovered in the late 1970's by field crews from Princeton University were significant in providing evidence of the early ontogenetic stages in North American dinosaurs. These specimens from the Campanian (Upper Cretaceous) Two Medicine Formation of Montana consist of over a dozen skeletons referable to the saurolophine hadrosaurid Maiasaura peeblesorum, but never fully figured or described. Here, we provide a more complete documentation of the morphology of these specimens, along with an examination of variation during a large span of the development of saurolophine hadrosaurids. Many ontogenetic changes in the available facial and mandibular elements are associated with the progressive elongation of the preorbital region of the skull and mandible. In the postcranium, limb bones change nearly isometrically, with exception of certain elements of the forelimb. Some cranial and postcranial characters commonly used for inferring hadrosaurid phylogenetic relationships remain invariable during the ontogeny of M. peeblesorum. This indicates that early ontogenetic stages may still provide a limited amount of character information useful for systematics and phylogenetic inference.

@article{doi107717peerj4734,
    author = "Prieto‐Márquez, Albert and Guenther, Merrilee F.",
    title = "Perinatal specimens of Maiasaura from the Upper Cretaceous of Montana (USA): insights into the early ontogeny of saurolophine hadrosaurid dinosaurs",
    year = "2018",
    journal = "PeerJ",
    abstract = "Perinatal specimens of hadrosaurids discovered in the late 1970's by field crews from Princeton University were significant in providing evidence of the early ontogenetic stages in North American dinosaurs. These specimens from the Campanian (Upper Cretaceous) Two Medicine Formation of Montana consist of over a dozen skeletons referable to the saurolophine hadrosaurid Maiasaura peeblesorum, but never fully figured or described. Here, we provide a more complete documentation of the morphology of these specimens, along with an examination of variation during a large span of the development of saurolophine hadrosaurids. Many ontogenetic changes in the available facial and mandibular elements are associated with the progressive elongation of the preorbital region of the skull and mandible. In the postcranium, limb bones change nearly isometrically, with exception of certain elements of the forelimb. Some cranial and postcranial characters commonly used for inferring hadrosaurid phylogenetic relationships remain invariable during the ontogeny of M. peeblesorum. This indicates that early ontogenetic stages may still provide a limited amount of character information useful for systematics and phylogenetic inference.",
    url = "https://doi.org/10.7717/peerj.4734",
    doi = "10.7717/peerj.4734",
    openalex = "W2803572907",
    references = "doi101371journalpone0141304"
}

@inproceedings{andzimmermann2019taphonomic,
    author = "Zimmermann, Peter K. and Lang, Asha D. and Roat, Gabriela E. and Velasquez, Kaylee R. and Tun, Sun M. and Irving, Katherine I. and Gomez, Sedalia P. and Clark, Nolan D. and Curry Rogers, Kristina A. and Rogers, Raymond R.",
    title = "TAPHONOMIC COMPARISON OF VERTEBRATE MICROFOSSIL BONEBEDS FROM THE UPPER CRETACEOUS JUDITH RIVER AND HELL CREEK FORMATIONS OF MONTANA",
    year = "2019",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2019am-335753",
    doi = "10.1130/abs/2019am-335753",
    openalex = "W2987305766"
}

In the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian-Maastrichtian [83-66 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by uneven sampling. Here we combine fossil occurrences with climatic and environmental modelling to quantify latest Cretaceous North American dinosaur habitat. Ecological niche modelling shows a Campanian-to-Maastrichtian habitability decrease in areas with present-day rock-outcrop. However, a continent-wide projection demonstrates habitat stability, or even a Campanian-to-Maastrichtian increase, that is not preserved. This reduction of the spatial sampling window resulted from formation of the proto-Rocky Mountains and sea-level regression. We suggest that Maastrichtian North American dinosaur diversity is therefore likely to be underestimated, with the apparent decline a product of sampling bias, and not due to a climatically-driven decrease in habitability as previously hypothesised.

@article{doi101038s41467019089972,
    author = "Chiarenza, Alfio Alessandro and Mannion, Philip D. and Lunt, Daniel J. and Farnsworth, Alex and Jones, Lewis A. and Kelland, Sarah-Jane and Allison, Peter A.",
    title = "Ecological niche modelling does not support climatically-driven dinosaur diversity decline before the Cretaceous/Paleogene mass extinction",
    year = "2019",
    journal = "Nature Communications",
    abstract = "In the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian-Maastrichtian [83-66 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by uneven sampling. Here we combine fossil occurrences with climatic and environmental modelling to quantify latest Cretaceous North American dinosaur habitat. Ecological niche modelling shows a Campanian-to-Maastrichtian habitability decrease in areas with present-day rock-outcrop. However, a continent-wide projection demonstrates habitat stability, or even a Campanian-to-Maastrichtian increase, that is not preserved. This reduction of the spatial sampling window resulted from formation of the proto-Rocky Mountains and sea-level regression. We suggest that Maastrichtian North American dinosaur diversity is therefore likely to be underestimated, with the apparent decline a product of sampling bias, and not due to a climatically-driven decrease in habitability as previously hypothesised.",
    url = "https://doi.org/10.1038/s41467-019-08997-2",
    doi = "10.1038/s41467-019-08997-2",
    openalex = "W2919866498",
    references = "doi101016jecolmodel201312012, doi101016jpalaeo201602033, doi101038nature15697, doi101038ncomms1815, doi101073pnas0901637106, doi101073pnas1521478113, doi10108008912969009386535, doi101111ecog03049, doi101111j13652664200601214x, doi101111j14724642201000725x, doi101111pala12329, doi101126science3287615, doi1012019781315140919, doi101371journalpone0079420, doi1018900721531, doi1023071931034, doi103897zookeys4698439, lehman1987late"
}

Noasaurines form an enigmatic group of small-bodied predatory theropod dinosaurs known from the Late Cretaceous of Gondwana. They are relatively rare, with notable records in Argentina and Madagascar, and possible remains reported for Brazil, India, and continental Africa. In south-central Brazil, the deposits of the Bauru Basin have yielded a rich tetrapod fauna, which is concentrated in the Bauru Group. The mainly aeolian deposits of the Caiuá Group, on the contrary, bear a scarce fossil record composed only of lizards, turtles, and pterosaurs. Here, we describe the first dinosaur of the Caiuá Group, which also represents the best-preserved theropod of the entire Bauru Basin known to date. The recovered skeletal parts (vertebrae, girdles, limbs, and scarce cranial elements) show that the new taxon was just over 1 m long, with a unique anatomy among theropods. The shafts of its metatarsals II and IV are very lateromedially compressed, as are the blade-like ungual phalanges of the respective digits. This implies that the new taxon could have been functionally monodactyl, with a main central weight-bearing digit, flanked by neighbouring elements positioned very close to digit III or even held free of the ground. Such anatomical adaptation is formerly unrecorded among archosaurs, but has been previously inferred from footprints of the same stratigraphic unit that yielded the new dinosaur. A phylogenetic analysis nests the new taxon within the Noasaurinae clade, which is unresolved because of the multiple alternative positions that Noasaurus leali can acquire in the optimal trees. The exclusion of the latter form results in positioning the new dinosaur as the sister-taxon of the Argentinean Velocisaurus unicus.

@article{doi101038s41598019453069,
    author = "Langer, Max C. and de Oliveira Martins, Neurides and Manzig, Paulo César and Ferreira, Gabriel S. and Marsola, Júlio C. A. and Fortes, Edison and Lima, Rosana N. and Sant’ana, Lucas Cesar Frediani and Vidal, Luciano and da Silva Lorençato, Rosangela Honório and Ezcurra, Martín D.",
    title = "A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous of south Brazil",
    year = "2019",
    journal = "Scientific Reports",
    abstract = "Noasaurines form an enigmatic group of small-bodied predatory theropod dinosaurs known from the Late Cretaceous of Gondwana. They are relatively rare, with notable records in Argentina and Madagascar, and possible remains reported for Brazil, India, and continental Africa. In south-central Brazil, the deposits of the Bauru Basin have yielded a rich tetrapod fauna, which is concentrated in the Bauru Group. The mainly aeolian deposits of the Caiuá Group, on the contrary, bear a scarce fossil record composed only of lizards, turtles, and pterosaurs. Here, we describe the first dinosaur of the Caiuá Group, which also represents the best-preserved theropod of the entire Bauru Basin known to date. The recovered skeletal parts (vertebrae, girdles, limbs, and scarce cranial elements) show that the new taxon was just over 1 m long, with a unique anatomy among theropods. The shafts of its metatarsals II and IV are very lateromedially compressed, as are the blade-like ungual phalanges of the respective digits. This implies that the new taxon could have been functionally monodactyl, with a main central weight-bearing digit, flanked by neighbouring elements positioned very close to digit III or even held free of the ground. Such anatomical adaptation is formerly unrecorded among archosaurs, but has been previously inferred from footprints of the same stratigraphic unit that yielded the new dinosaur. A phylogenetic analysis nests the new taxon within the Noasaurinae clade, which is unresolved because of the multiple alternative positions that Noasaurus leali can acquire in the optimal trees. The exclusion of the latter form results in positioning the new dinosaur as the sister-taxon of the Argentinean Velocisaurus unicus.",
    url = "https://doi.org/10.1038/s41598-019-45306-9",
    doi = "10.1038/s41598-019-45306-9",
    openalex = "W2953934698",
    references = "crossref1976allosaurus, doi101016jcub201610043, doi101016jmarpetgeo201602027, doi101038261129a0, doi10108002724634199910011178, doi101086273307, doi101111cla12160, doi101111j109600311994tb00179x, doi101111j10960031200800217x, doi101111joa12719, doi101111pala12329, doi101111zoj12425, doi1011646zootaxa375911, doi101371journalpone0062047, doi101590s000137652011000100003, doi103998mpub9690664, doi105281zenodo16171435, openalexw2894525608"
}

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 non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.

@article{doi101139cjes20190019,
    author = "Eberth, David A. and Kamo, Sandra L.",
    title = "High-precision U–Pb CA–ID–TIMS dating and chronostratigraphy of the dinosaur-rich Horseshoe Canyon Formation (Upper Cretaceous, Campanian–Maastrichtian), Red Deer River valley, Alberta, Canada",
    year = "2019",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.",
    url = "https://doi.org/10.1139/cjes-2019-0019",
    doi = "10.1139/cjes-2019-0019",
    openalex = "W2979872101",
    references = "andeberth2016new, doi101007springerreference4923, doi1010160016703773902135, doi101016jchemgeo200503011, doi101016jgca200509007, doi101016jgca201006017, doi101016s0009254196000332, doi101016s0195667105800308, doi101073pnas1313334111, doi101103physrevc41889, doi101126science1154339, doi101126science1230492, doi101139cjes20120185, doi101371journalpone0188426, doi104202app20110033, doi105860choice435902, openalexw2989049194"
}

@inproceedings{andsankey2020why,
    author = "Sankey, Julia",
    title = "WHY SWEAT THE SMALL STUFF? NEW DISCOVERIES OF BABY DINOSAURS, TINY SHARKS, AND OTHER MICROVERTEBRATE FOSSILS, LATEST CRETACEOUS HELL CREEK FORMATION, NORTH DAKOTA",
    year = "2020",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2020cd-347371",
    doi = "10.1130/abs/2020cd-347371",
    openalex = "W3016779821"
}

The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO 2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.

@article{doi101073pnas2006087117,
    author = "Chiarenza, Alfio Alessandro and Farnsworth, Alexander and Mannion, Philip D. and Lunt, Daniel J. and Valdes, Paul J. and Morgan, Joanna and Allison, Peter A.",
    title = "Asteroid impact, not volcanism, caused the end-Cretaceous dinosaur extinction",
    year = "2020",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO 2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.",
    url = "https://doi.org/10.1073/pnas.2006087117",
    doi = "10.1073/pnas.2006087117",
    openalex = "W3038551147",
    references = "alvarez1980extraterrestrial, doi101007s1091400569434, doi101016jcub201804062, doi101016s0012825200000374, doi10102993jd02553, doi101038s41467019089972, doi101073pnas1211526110, doi101073pnas1319253111, doi101111brv12128, doi101111ecog03049, doi101111j14724642201000725x, doi101111j16000587200805742x, doi101126sciadvaat4858, doi101126science1177265, doi101126science1229237, doi101126science20844481095, doi101126science21545391501, doi101126scienceaau2422, doi101126scienceaay2268, doi1011302014250315, doi1011302014250502, doi101130spe247, doi101144sp35813"
}

Abstract In the Cretaceous of North America, environmental sensitivity and habitat specialization have been hypothesized to explain the surprisingly restricted geographic ranges of many large-bodied dinosaurs. Understanding the drivers behind this are key to determining broader trends of dinosaur species and community response to climate change under greenhouse conditions. However, previous studies of this question have commonly examined only small components of the paleo-ecosystem or operated without comparison to similar modern systems from which to constrain interpretations. Here we perform a high-resolution multi-taxic δ13C and δ18O study of a Cretaceous coastal floodplain ecosystem, focusing on species interactions and paleotemperature estimation, and compare with similar data from extant systems. Bioapatite δ13C preserves predator-prey offsets between tyrannosaurs and ornithischians (large herbivorous dinosaurs), and between aquatic reptiles and fish. Large ornithischians had broadly overlapping stable isotope ranges, contrary to hypothesized niche partitioning driven by specialization on coastal or inland subhabitat use. Comparisons to a modern analogue coastal floodplain show similar patterns of ecological guild structure and aquatic-terrestrial resource interchange. Multi-taxic oxygen isotope temperature estimations yield results for the Campanian of Alberta (Canada) consistent with the few other paleotemperature proxies available, and are validated when applied for extant species from a modern coastal floodplain, suggesting that this approach is a simple and effective avenue for paleoenvironmental reconstruction. Together, these new data suggest that dinosaur niche partitioning was more complex than previously hypothesized, and provide a framework for future research on dinosaur-dominated Mesozoic floodplain communities.

@article{doi101130g473991,
    author = "Cullen, Thomas M. and Longstaffe, Fred J. and Wortmann, Ulrich G. and Huang, L. and Fanti, Federico and Goodwin, Mark B. and Ryan, Michael J. and Evans, David C.",
    title = "Large-scale stable isotope characterization of a Late Cretaceous dinosaur-dominated ecosystem",
    year = "2020",
    journal = "Geology",
    abstract = "Abstract In the Cretaceous of North America, environmental sensitivity and habitat specialization have been hypothesized to explain the surprisingly restricted geographic ranges of many large-bodied dinosaurs. Understanding the drivers behind this are key to determining broader trends of dinosaur species and community response to climate change under greenhouse conditions. However, previous studies of this question have commonly examined only small components of the paleo-ecosystem or operated without comparison to similar modern systems from which to constrain interpretations. Here we perform a high-resolution multi-taxic δ13C and δ18O study of a Cretaceous coastal floodplain ecosystem, focusing on species interactions and paleotemperature estimation, and compare with similar data from extant systems. Bioapatite δ13C preserves predator-prey offsets between tyrannosaurs and ornithischians (large herbivorous dinosaurs), and between aquatic reptiles and fish. Large ornithischians had broadly overlapping stable isotope ranges, contrary to hypothesized niche partitioning driven by specialization on coastal or inland subhabitat use. Comparisons to a modern analogue coastal floodplain show similar patterns of ecological guild structure and aquatic-terrestrial resource interchange. Multi-taxic oxygen isotope temperature estimations yield results for the Campanian of Alberta (Canada) consistent with the few other paleotemperature proxies available, and are validated when applied for extant species from a modern coastal floodplain, suggesting that this approach is a simple and effective avenue for paleoenvironmental reconstruction. Together, these new data suggest that dinosaur niche partitioning was more complex than previously hypothesized, and provide a framework for future research on dinosaur-dominated Mesozoic floodplain communities.",
    url = "https://doi.org/10.1130/g47399.1",
    doi = "10.1130/g47399.1",
    openalex = "W3011136744",
    references = "doi101007b110345, doi101016003101828790040x, doi101016jepsl200407015, doi101016jpalaeo201206027, doi101016s0016703796002402, doi101038s41598019517095, doi101073pnas1004933107, doi101073pnas1521478113, doi101098rsos161086, doi101186147267851314, doi101186s1289801601068, doi101371journalpone0012292, doi1016660094837336180, doi1018901540929520075429anfie20co2, doi102475ajs3047612"
}

Abstract The end-Cretaceous (K/Pg) mass extinction event is the most recent and well-understood of the “big five” and triggered establishment of modern terrestrial ecosystem structure. Despite the depth of research into this event, our knowledge of upper Maastrichtian terrestrial deposits globally relies primarily on assemblage-level data limited to a few well-sampled formations in North America, the Hell Creek and Lance Formations. These assemblages disproportionally affect our interpretations of this important interval. Multiple investigations have quantified diversity patterns within these assemblages, but the potential effect of formation-level size-dependent taphonomic biases and their implications on extinction dynamics remains unexplored. Here, the relationship between taphonomy and body size of the Hell Creek Formation and Lance Formation dinosaurs and mammals are quantitatively analyzed. Small-bodied dinosaur taxa (<70 kg) are consistently less complete, unlikely to be articulated, and delayed in their description relative to their large-bodied counterparts. Family-level abundance (particularly skeletons) is strongly tied to body mass, and the relative abundance of juveniles of large-bodied taxa similarly is underrepresented. Mammals show similar but nonsignificant trends. The results are remarkably similar to those from the Campanian-aged Dinosaur Park Formation, suggesting a widespread strong taphonomic bias against the preservation of small taxa, which will result in their seemingly depauperate diversity within the assemblage. This taphonomically skewed view of diversity and abundance of small-bodied taxa amid our best late Maastrichtian samples has significant implications for understanding speciation and extinction dynamics (e.g., size-dependent extinction selectivity) across the K/Pg boundary.

@article{doi101017pab202135,
    author = "Brown, Caleb M. and Campione, Nicolás E. and Wilson, Gregory P. and Evans, David C.",
    title = "Size-driven preservational and macroecological biases in the latest Maastrichtian terrestrial vertebrate assemblages of North America",
    year = "2021",
    journal = "Paleobiology",
    abstract = "Abstract The end-Cretaceous (K/Pg) mass extinction event is the most recent and well-understood of the “big five” and triggered establishment of modern terrestrial ecosystem structure. Despite the depth of research into this event, our knowledge of upper Maastrichtian terrestrial deposits globally relies primarily on assemblage-level data limited to a few well-sampled formations in North America, the Hell Creek and Lance Formations. These assemblages disproportionally affect our interpretations of this important interval. Multiple investigations have quantified diversity patterns within these assemblages, but the potential effect of formation-level size-dependent taphonomic biases and their implications on extinction dynamics remains unexplored. Here, the relationship between taphonomy and body size of the Hell Creek Formation and Lance Formation dinosaurs and mammals are quantitatively analyzed. Small-bodied dinosaur taxa (<70 kg) are consistently less complete, unlikely to be articulated, and delayed in their description relative to their large-bodied counterparts. Family-level abundance (particularly skeletons) is strongly tied to body mass, and the relative abundance of juveniles of large-bodied taxa similarly is underrepresented. Mammals show similar but nonsignificant trends. The results are remarkably similar to those from the Campanian-aged Dinosaur Park Formation, suggesting a widespread strong taphonomic bias against the preservation of small taxa, which will result in their seemingly depauperate diversity within the assemblage. This taphonomically skewed view of diversity and abundance of small-bodied taxa amid our best late Maastrichtian samples has significant implications for understanding speciation and extinction dynamics (e.g., size-dependent extinction selectivity) across the K/Pg boundary.",
    url = "https://doi.org/10.1017/pab.2021.35",
    doi = "10.1017/pab.2021.35",
    openalex = "W3209125731",
    references = "doi101002ar24241, doi101126science239483510b, doi101126scienceabd9220"
}

A new genus and species of non-hadrosaurid hadrosauriform dinosaur, Brighstoneus simmondsi gen. et sp. nov., is described from the Lower Cretaceous Wessex Formation of the Isle of Wight. The new taxon has two autapomorphies, a nasal having a modest nasal bulla with convex sides, and primary and accessory ridges on the lingual aspect of the maxillary crown. The dentary has at least 28 alveolar positions, which is the highest number recorded in an ornithopod with non-parallel sided alveoli, creating a character combination that is unique within Iguanodontia. The hadrosauriform fauna of the Barremian–Aptian Wealden Group on both the Isle of Wight and mainland England has been represented for almost a century by just two taxa, the robust Iguanodon bernissartensis and the more gracile Mantellisaurus atherfieldensis, with referred material often being fragmentary or based on unassociated elements. This discovery increases the known hadrosauriform diversity in England and, together with recent discoveries in Spain, suggests that their diversity in the upper Wealden of Europe was considerably wider than initially realized. This find also has important implications for the validity of the Mantellisaurus atherfieldensis hypodigm, and a reassessment of existing material is suggested.http://zoobank.org/urn:lsid:zoobank.org:pub:31F0D48F-C1DA-406E-A811-1F5937ED19F4

@article{doi1010801477201920211978005,
    author = "Lockwood, Jeremy A. F. and Martill, David M. and Maidment, Susannah C. R.",
    title = "A new hadrosauriform dinosaur from the Wessex Formation, Wealden Group (Early Cretaceous), of the Isle of Wight, southern England",
    year = "2021",
    journal = "Journal of Systematic Palaeontology",
    abstract = "A new genus and species of non-hadrosaurid hadrosauriform dinosaur, Brighstoneus simmondsi gen. et sp. nov., is described from the Lower Cretaceous Wessex Formation of the Isle of Wight. The new taxon has two autapomorphies, a nasal having a modest nasal bulla with convex sides, and primary and accessory ridges on the lingual aspect of the maxillary crown. The dentary has at least 28 alveolar positions, which is the highest number recorded in an ornithopod with non-parallel sided alveoli, creating a character combination that is unique within Iguanodontia. The hadrosauriform fauna of the Barremian–Aptian Wealden Group on both the Isle of Wight and mainland England has been represented for almost a century by just two taxa, the robust Iguanodon bernissartensis and the more gracile Mantellisaurus atherfieldensis, with referred material often being fragmentary or based on unassociated elements. This discovery increases the known hadrosauriform diversity in England and, together with recent discoveries in Spain, suggests that their diversity in the upper Wealden of Europe was considerably wider than initially realized. This find also has important implications for the validity of the Mantellisaurus atherfieldensis hypodigm, and a reassessment of existing material is suggested.http://zoobank.org/urn:lsid:zoobank.org:pub:31F0D48F-C1DA-406E-A811-1F5937ED19F4",
    url = "https://doi.org/10.1080/14772019.2021.1978005",
    doi = "10.1080/14772019.2021.1978005",
    openalex = "W3211438913",
    references = "doi101111brv12666, doi101111zoj12193, doi101371journalpone0045712, gates2018a, tsogtbaatar2019a"
}

Despite dominating biodiversity in the Mesozoic, dinosaurs were not speciose. Oviparity constrained even gigantic dinosaurs to less than 15 kg at birth; growth through multiple morphologies led to the consumption of different resources at each stage. Such disparity between neonates and adults could have influenced the structure and diversity of dinosaur communities. Here, we quantified this effect for 43 communities across 136 million years and seven continents. We found that megatheropods (more than 1000 kg) such as tyrannosaurs had specific effects on dinosaur community structure. Although herbivores spanned the body size range, communities with megatheropods lacked carnivores weighing 100 to 1000 kg. We demonstrate that juvenile megatheropods likely filled the mesocarnivore niche, resulting in reduced overall taxonomic diversity. The consistency of this pattern suggests that ontogenetic niche shift was an important factor in generating dinosaur community structure and diversity.

@article{doi101126scienceabd9220,
    author = "Schroeder, Katlin and Lyons, S. Kathleen and Smith, Felisa A.",
    title = "The influence of juvenile dinosaurs on community structure and diversity",
    year = "2021",
    journal = "Science",
    abstract = "Despite dominating biodiversity in the Mesozoic, dinosaurs were not speciose. Oviparity constrained even gigantic dinosaurs to less than 15 kg at birth; growth through multiple morphologies led to the consumption of different resources at each stage. Such disparity between neonates and adults could have influenced the structure and diversity of dinosaur communities. Here, we quantified this effect for 43 communities across 136 million years and seven continents. We found that megatheropods (more than 1000 kg) such as tyrannosaurs had specific effects on dinosaur community structure. Although herbivores spanned the body size range, communities with megatheropods lacked carnivores weighing 100 to 1000 kg. We demonstrate that juvenile megatheropods likely filled the mesocarnivore niche, resulting in reduced overall taxonomic diversity. The consistency of this pattern suggests that ontogenetic niche shift was an important factor in generating dinosaur community structure and diversity.",
    url = "https://doi.org/10.1126/science.abd9220",
    doi = "10.1126/science.abd9220",
    openalex = "W3130388974",
    references = "doi101007s0011401311075, doi101016jcub201610043, doi101016jpalaeo200909018, doi101016jpalaeo201206024, doi101017s0094837300016900, doi101038202234a0, doi101038nature02699, doi101038nature24679, doi101038ncomms3827, doi101038ncomms4788, doi101038s41598017052726, doi101038s41598019517095, doi101038s41598020576677, doi101073pnas1600140113, doi101080027246342012717567, doi101080089129632012688589, doi1010800891296320181563784, doi101093zoolinneanzly068, doi101098rsos161086, doi101098rspb20090229, doi101111j1469185x201000137x, doi101111j146979981985tb04915x, doi101111zoj12193, doi101126sciadvaax6250, doi101126science1161833, doi101127njgpm19821982440, doi101139cjes20120185, doi101139cjes20170034, doi101139cjes20190019, doi101139e11017, doi101146annurevecolsys151393, doi101146annureves15110184002141, doi1011646zootaxa375911, doi1012066391, doi101371journalpbio1001853, doi101371journalpone0024487, doi101371journalpone0032623, doi101371journalpone0044012, doi101371journalpone0054329, doi101371journalpone0092022, doi101371journalpone0093190, doi101371journalpone0108804, doi101371journalpone0112055, doi101371journalpone0125819, doi101371journalpone0151453, doi101371journalpone0175253, doi101666100041, doi1016710272463420000200115lbhoth20co2, doi1016710272463420050250897anotmf20co2, doi1016710272463420072787antdtf20co2, doi1017161paleo180818764, doi1017161pc180818764, doi1018435vamp29362, doi102110palo2014084, doi1033740140540102, doi104202app20090075, doi104202app20120121, doi105281zenodo3382461, doi105962bhltitle115853, doi107717peerj7803, doi107717peerj9192, gates2018a, openalexw2912219260, osmólska1982hulsanpes, padian1989presence, tsogtbaatar2019a, vonhuene1923carnivorous"
}

Well-sampled dinosaur communities from the Jurassic through the early Late Cretaceous show greater taxonomic diversity among larger (>50 kg) theropod taxa than communities of the Campano-Maastrichtian, particularly to those of eastern/central Asia and Laramidia. The large carnivore guilds in Asiamerican assemblages are monopolized by tyrannosaurids, with adult medium-sized (50–500 kg) predators rare or absent. In contrast, various clades of theropods are found to occupy these body sizes in earlier faunas, including early tyrannosauroids. Assemblages with “missing middle-sized” predators are not found to have correspondingly sparser diversity of potential prey species recorded in these same faunas. The “missing middle-sized” niches in the theropod guilds of Late Cretaceous Laramidia and Asia may have been assimilated by juvenile and subadults of tyrannosaurid species, functionally distinct from their adult ecomorphologies. It is speculated that if tyrannosaurids assimilated the niches previously occupied by mid-sized theropod predators, we would expect the evolution of distinct transitions in morphology and possibly the delay of the achievement of somatic maturity in species of this taxon.

@article{doi101139cjes20200174,
    author = "Holtz, Thomas R.",
    title = "Theropod guild structure and the tyrannosaurid niche assimilation hypothesis: implications for predatory dinosaur macroecology and ontogeny in later Late Cretaceous Asiamerica 1",
    year = "2021",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Well-sampled dinosaur communities from the Jurassic through the early Late Cretaceous show greater taxonomic diversity among larger (>50 kg) theropod taxa than communities of the Campano-Maastrichtian, particularly to those of eastern/central Asia and Laramidia. The large carnivore guilds in Asiamerican assemblages are monopolized by tyrannosaurids, with adult medium-sized (50–500 kg) predators rare or absent. In contrast, various clades of theropods are found to occupy these body sizes in earlier faunas, including early tyrannosauroids. Assemblages with “missing middle-sized” predators are not found to have correspondingly sparser diversity of potential prey species recorded in these same faunas. The “missing middle-sized” niches in the theropod guilds of Late Cretaceous Laramidia and Asia may have been assimilated by juvenile and subadults of tyrannosaurid species, functionally distinct from their adult ecomorphologies. It is speculated that if tyrannosaurids assimilated the niches previously occupied by mid-sized theropod predators, we would expect the evolution of distinct transitions in morphology and possibly the delay of the achievement of somatic maturity in species of this taxon.",
    url = "https://doi.org/10.1139/cjes-2020-0174",
    doi = "10.1139/cjes-2020-0174",
    openalex = "W3168560974",
    references = "doi101016jcub201803042, doi101017pab201519, doi101017s0094837300011891, doi10103846266, doi101038nature02699, doi101038ncomms3827, doi101038s4155901908880, doi101038s41598019517095, doi101038srep20252, doi101073pnas1600140113, doi101093nsrnwu055, doi101098rspb20202258, doi101111brv12638, doi101111j1469185x201000137x, doi101111j15023931200900187x, doi101126sciadvaax6250, doi101126science1065522, doi101126science1161833, doi101126science28454232137, doi101139cjes20120185, doi101139cjes20170031, doi101139cjes20190019, doi101371journalpone0054329, doi101371journalpone0188426, doi1017161paleo180818764, doi1023071942327, doi1023072411924, doi1029920070860302, doi103897zookeys92847517, doi107717peerj9192, openalexw2183707334, openalexw2971401580"
}

Rhabdodontid dinosaurs were a group of medium-sized iguanodontian ornithopods from the Late Cretaceous of Europe. The uppermost Cretaceous continental deposits from the Haţeg Basin of western Romania yielded a very rich assemblage of vertebrates including abundant rhabdodontid remains, which have been exclusively referred to the genus Zalmoxes thus far. Here we describe a new rhabdodontid dinosaur, Transylvanosaurus platycephalus gen. et sp. nov., from the uppermost Cretaceous of the Haţeg Basin. The holotype of the new taxon was discovered in early–late Maastrichtian strata near Pui in the eastern part of the basin and comprises the articulated basicranium and both frontals. Transylvanosaurus differs from all previously reported rhabdodontids in having particularly wide and crested frontals, elongated and straight paroccipital processes that make only a gentle lateral curve and project mostly posterolaterally, prominent and massive prootic processes that extend mainly anterolaterally and ventrally, wide and crest-like basal tubera that meet the long axis of the braincase at a very flat angle, widely splayed basipterygoid processes that extend mainly ventrolaterally and slightly anteriorly, as well as a well-developed notch on the lateral side of the basicranium that is continuous, straight, and inclined anteroventrally. Phylogenetic analyses employing two different datasets consistently recovered the new taxon within the Rhabdodontidae, at the base of the iguanodontian radiation. Based on the morphological comparisons presented herein, we propose a particularly close relationship between Transylvanosaurus and Rhabdodon from southern France, which in turn provides evidence for a more complex biogeographic history of the Rhabdodontidae than previously thought.

@article{doi1010800272463420222133610,
    author = "Augustin, Felix J. and Bastiaans, Dylan and Dumbravă, Mihai D. and Csiki‐Sava, Zoltán",
    title = "A new ornithopod dinosaur, Transylvanosaurus platycephalus gen. et sp. nov. (Dinosauria: Ornithischia), from the Upper Cretaceous of the Haţeg Basin, Romania",
    year = "2022",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "Rhabdodontid dinosaurs were a group of medium-sized iguanodontian ornithopods from the Late Cretaceous of Europe. The uppermost Cretaceous continental deposits from the Haţeg Basin of western Romania yielded a very rich assemblage of vertebrates including abundant rhabdodontid remains, which have been exclusively referred to the genus Zalmoxes thus far. Here we describe a new rhabdodontid dinosaur, Transylvanosaurus platycephalus gen. et sp. nov., from the uppermost Cretaceous of the Haţeg Basin. The holotype of the new taxon was discovered in early–late Maastrichtian strata near Pui in the eastern part of the basin and comprises the articulated basicranium and both frontals. Transylvanosaurus differs from all previously reported rhabdodontids in having particularly wide and crested frontals, elongated and straight paroccipital processes that make only a gentle lateral curve and project mostly posterolaterally, prominent and massive prootic processes that extend mainly anterolaterally and ventrally, wide and crest-like basal tubera that meet the long axis of the braincase at a very flat angle, widely splayed basipterygoid processes that extend mainly ventrolaterally and slightly anteriorly, as well as a well-developed notch on the lateral side of the basicranium that is continuous, straight, and inclined anteroventrally. Phylogenetic analyses employing two different datasets consistently recovered the new taxon within the Rhabdodontidae, at the base of the iguanodontian radiation. Based on the morphological comparisons presented herein, we propose a particularly close relationship between Transylvanosaurus and Rhabdodon from southern France, which in turn provides evidence for a more complex biogeographic history of the Rhabdodontidae than previously thought.",
    url = "https://doi.org/10.1080/02724634.2022.2133610",
    doi = "10.1080/02724634.2022.2133610",
    openalex = "W4309859469",
    references = "doi101016jcretres201509003, doi101080027246342013746229, doi1010800891296320201793979, doi1010801477201920171371258, doi101111j10963642201000620x, doi107717peerj12362"
}

The Late Cretaceous (Maastrichtian) Ruth Mason Dinosaur Quarry (RMDQ) represents a monodominant Edmontosaurus annectens bonebed from the Hell Creek Formation of South Dakota and has been determined as a catastrophic death assemblage likely belonging to a single population, providing an ideal sample to investigate hadrosaurid growth and population dynamics. For this study, size-frequency distributions were constructed from linear measurements of long bones (humeri, femora, tibiae) from RMDQ that revealed five relatively distinct size classes along a generally right-skewed distribution, which is consistent with a catastrophic assemblage. To test the relationship between morphological size ranges and ontogenetic age classes, subsets from each size-frequency peak were transversely thin-sectioned at mid-diaphysis to conduct an ontogenetic age assessment based on growth marks and observations of the bone microstructure. When combining these independent datasets, growth marks aligned with size-frequency peaks, with the exclusion of the overlapping subadult-adult size range, indicating a strong size-age relationship in early ontogeny. A growth curve analysis of tibiae indicated that E. annectens exhibited a similar growth trajectory to the Campanian hadrosaurid Maiasaura, although attaining a much larger asymptotic body size by about 9 years of age, further suggesting that the clade as a whole may have inherited a similar growth strategy. This rich new dataset for E. annectens provides new perspectives on other hypotheses of hadrosaurid life history. When the RMDQ population was compared with size distributions from other hadrosaurid bonebed assemblages, juveniles (categorized as ages one and two) were either completely absent from or heavily underrepresented in the samples, providing support for the hypothesized segregation between juvenile and adult hadrosaurids. Osteohistological comparison with material from polar and temperate populations of Edmontosaurus revealed that previous conclusions correlating osteohistological growth patterns with the strength of environmental stressors were a result of sampling non-overlapping ontogenetic growth stages.

@article{doi101111joa13679,
    author = "Wosik, Mateusz and Evans, David C.",
    title = "Osteohistological and taphonomic life‐history assessment of Edmontosaurus annectens (Ornithischia: Hadrosauridae) from the Late Cretaceous (Maastrichtian) Ruth Mason dinosaur quarry, South Dakota, United States, with implication for ontogenetic segregation between juvenile and adult hadrosaurids",
    year = "2022",
    journal = "Journal of Anatomy",
    abstract = "The Late Cretaceous (Maastrichtian) Ruth Mason Dinosaur Quarry (RMDQ) represents a monodominant Edmontosaurus annectens bonebed from the Hell Creek Formation of South Dakota and has been determined as a catastrophic death assemblage likely belonging to a single population, providing an ideal sample to investigate hadrosaurid growth and population dynamics. For this study, size-frequency distributions were constructed from linear measurements of long bones (humeri, femora, tibiae) from RMDQ that revealed five relatively distinct size classes along a generally right-skewed distribution, which is consistent with a catastrophic assemblage. To test the relationship between morphological size ranges and ontogenetic age classes, subsets from each size-frequency peak were transversely thin-sectioned at mid-diaphysis to conduct an ontogenetic age assessment based on growth marks and observations of the bone microstructure. When combining these independent datasets, growth marks aligned with size-frequency peaks, with the exclusion of the overlapping subadult-adult size range, indicating a strong size-age relationship in early ontogeny. A growth curve analysis of tibiae indicated that E. annectens exhibited a similar growth trajectory to the Campanian hadrosaurid Maiasaura, although attaining a much larger asymptotic body size by about 9 years of age, further suggesting that the clade as a whole may have inherited a similar growth strategy. This rich new dataset for E. annectens provides new perspectives on other hypotheses of hadrosaurid life history. When the RMDQ population was compared with size distributions from other hadrosaurid bonebed assemblages, juveniles (categorized as ages one and two) were either completely absent from or heavily underrepresented in the samples, providing support for the hypothesized segregation between juvenile and adult hadrosaurids. Osteohistological comparison with material from polar and temperate populations of Edmontosaurus revealed that previous conclusions correlating osteohistological growth patterns with the strength of environmental stressors were a result of sampling non-overlapping ontogenetic growth stages.",
    url = "https://doi.org/10.1111/joa.13679",
    doi = "10.1111/joa.13679",
    openalex = "W4284889573",
    references = "doi101007s1082700901804, doi101017pab20202, doi101017s0094837300005820, doi101017s0094837300021308, doi10103835086558, doi101111joa13679, doi101162neco20071961503, doi101186174170071060, doi1016710272463420000200115lbhoth20co2, doi102113gsrocky8specialpaper11, doi1023073802723, doi10560219780801881206, doi107717peerj11290"
}

A new spinosaurid genus and species is described based on the right maxilla and five caudal vertebrae of a single specimen from the Arcillas de Morella Formation (Early Cretaceous) at the locality of Cinctorres (Castellón, Spain). Protathlitis cinctorrensis gen. et sp. nov. is diagnosed by one autapomorphic feature as well as by a unique combination of characters. The autapomorphy includes a subcircular depression in the anterior corner of the antorbital fossa in the maxilla. The new Iberian species is recovered as a basal baryonychine. The recognition of Protathlitis cinctorrensis gen. et sp. nov. as the first baryonychine dinosaur species identified from the Arcillas de Morella Formation (late Barremian) from the same time as Vallibonavenatrix cani, the first spinosaurine dinosaur from the same formation in the Morella subbasin (Maestrat Basin, eastern Spain), indicates that the Iberian Peninsula was home to a highly diverse assemblage of medium-to-large bodied spinosaurid dinosaurs. It seems that spinosaurids appeared during the Early Cretaceous in Laurasia, with the two subfamilies occupying the western part of Europe during this period. Later, during the Barremian-Aptian, they migrated to Africa and Asia, where they would diversify. In Europe, baryonychines were dominant, while in Africa, spinosaurines were most abundant.

@article{doi101038s41598023334182,
    author = "Cubedo, Andrés Santos and de Santisteban, Carlos and Poza, Begoña and Meseguer, Sergi",
    title = "A new spinosaurid dinosaur species from the Early Cretaceous of Cinctorres (Spain)",
    year = "2023",
    journal = "Scientific Reports",
    abstract = "A new spinosaurid genus and species is described based on the right maxilla and five caudal vertebrae of a single specimen from the Arcillas de Morella Formation (Early Cretaceous) at the locality of Cinctorres (Castellón, Spain). Protathlitis cinctorrensis gen. et sp. nov. is diagnosed by one autapomorphic feature as well as by a unique combination of characters. The autapomorphy includes a subcircular depression in the anterior corner of the antorbital fossa in the maxilla. The new Iberian species is recovered as a basal baryonychine. The recognition of Protathlitis cinctorrensis gen. et sp. nov. as the first baryonychine dinosaur species identified from the Arcillas de Morella Formation (late Barremian) from the same time as Vallibonavenatrix cani, the first spinosaurine dinosaur from the same formation in the Morella subbasin (Maestrat Basin, eastern Spain), indicates that the Iberian Peninsula was home to a highly diverse assemblage of medium-to-large bodied spinosaurid dinosaurs. It seems that spinosaurids appeared during the Early Cretaceous in Laurasia, with the two subfamilies occupying the western part of Europe during this period. Later, during the Barremian-Aptian, they migrated to Africa and Asia, where they would diversify. In Europe, baryonychines were dominant, while in Africa, spinosaurines were most abundant.",
    url = "https://doi.org/10.1038/s41598-023-33418-2",
    doi = "10.1038/s41598-023-33418-2",
    openalex = "W4377092856",
    references = "doi103897zookeys92847517, sánchezhernández2007dinosaurs"
}

Gondwanan dinosaur faunae during the 20 Myr preceding the Cretaceous-Palaeogene (K/Pg) extinction included several lineages that were absent or poorly represented in Laurasian landmasses. Among these, the South American fossil record contains diverse abelisaurids, arguably the most successful groups of carnivorous dinosaurs from Gondwana in the Cretaceous, reaching their highest diversity towards the end of this period. Here we describe Koleken inakayali gen. et sp. n., a new abelisaurid from the La Colonia Formation (Maastrichtian, Upper Cretaceous) of Patagonia. Koleken inakayali is known from several skull bones, an almost complete dorsal series, complete sacrum, several caudal vertebrae, pelvic girdle and almost complete hind limbs. The new abelisaurid shows a unique set of features in the skull and several anatomical differences from Carnotaurus sastrei (the only other abelisaurid known from the La Colonia Formation). Koleken inakayali is retrieved as a brachyrostran abelisaurid, clustered with other South American abelisaurids from the latest Cretaceous (Campanian-Maastrichtian), such as Aucasaurus, Niebla and Carnotaurus. Leveraging our phylogeny estimates, we explore rates of morphological evolution across ceratosaurian lineages, finding them to be particularly high for elaphrosaurine noasaurids and around the base of Abelisauridae, before the Early Cretaceous radiation of the latter clade. The Noasauridae and their sister clade show contrasting patterns of morphological evolution, with noasaurids undergoing an early phase of accelerated evolution of the axial and hind limb skeleton in the Jurassic, and the abelisaurids exhibiting sustained high rates of cranial evolution during the Early Cretaceous. These results provide much needed context for the evolutionary dynamics of ceratosaurian theropods, contributing to broader understanding of macroevolutionary patterns across dinosaurs.

@article{doi101111cla12583,
    author = "Pol, Diego and Baiano, Mattia A. and Černý, David and Novas, Fernando E. and Cerda, Ignacio A. and Pittman, Michael",
    title = "A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria",
    year = "2024",
    journal = "Cladistics",
    abstract = "Gondwanan dinosaur faunae during the 20 Myr preceding the Cretaceous-Palaeogene (K/Pg) extinction included several lineages that were absent or poorly represented in Laurasian landmasses. Among these, the South American fossil record contains diverse abelisaurids, arguably the most successful groups of carnivorous dinosaurs from Gondwana in the Cretaceous, reaching their highest diversity towards the end of this period. Here we describe Koleken inakayali gen. et sp. n., a new abelisaurid from the La Colonia Formation (Maastrichtian, Upper Cretaceous) of Patagonia. Koleken inakayali is known from several skull bones, an almost complete dorsal series, complete sacrum, several caudal vertebrae, pelvic girdle and almost complete hind limbs. The new abelisaurid shows a unique set of features in the skull and several anatomical differences from Carnotaurus sastrei (the only other abelisaurid known from the La Colonia Formation). Koleken inakayali is retrieved as a brachyrostran abelisaurid, clustered with other South American abelisaurids from the latest Cretaceous (Campanian-Maastrichtian), such as Aucasaurus, Niebla and Carnotaurus. Leveraging our phylogeny estimates, we explore rates of morphological evolution across ceratosaurian lineages, finding them to be particularly high for elaphrosaurine noasaurids and around the base of Abelisauridae, before the Early Cretaceous radiation of the latter clade. The Noasauridae and their sister clade show contrasting patterns of morphological evolution, with noasaurids undergoing an early phase of accelerated evolution of the axial and hind limb skeleton in the Jurassic, and the abelisaurids exhibiting sustained high rates of cranial evolution during the Early Cretaceous. These results provide much needed context for the evolutionary dynamics of ceratosaurian theropods, contributing to broader understanding of macroevolutionary patterns across dinosaurs.",
    url = "https://doi.org/10.1111/cla.12583",
    doi = "10.1111/cla.12583",
    openalex = "W4398169218",
    references = "doi101002spp21375, doi101016jcretres2019104312, doi101016jcretres2020104408, doi101016jcretres2021104829, doi101038s41598019453069, doi101038s41598022155356, doi101038srep44942, doi101080027246342013776562, doi1010800272463420201877151, doi1010801477201920222093661, doi101111brv12666, doi101111cla12524, doi101111zoj12425, doi1011646zootaxa375911, doi101371journalpone0062047, doi101371journalpone0088905, doi105852crpalevol2020v19a6, doi107717peerj5976"
}