Dockum formation

@book{openalexw337536883,
    author = "Estes, Richard",
    title = "Fossil vertebrates from the late Cretaceous Lance formation, eastern Wyoming",
    year = "1964",
    booktitle = "University of California Press eBooks",
    openalex = "W337536883"
}

@misc{wright1971an,
    author = "Wright, James C. and Finch, Warren I.",
    title = "An annotated bibliography of fauna and flora described from the Dockum Group of Triassic age in eastern New Mexico and West Texas",
    year = "1971",
    booktitle = "Open-File Report",
    url = "https://doi.org/10.3133/ofr71333",
    doi = "10.3133/ofr71333",
    openalex = "W31610353",
    references = "doi101086622860, openalexw2685376236"
}

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

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

@inproceedings{gregory1972vertebrate,
    author = "Gregory, Joseph P.",
    title = "Vertebrate fauna of the Dockum Group, Triassic, eastern New Mexico and West Texas",
    year = "1972",
    booktitle = "East-Central New Mexico",
    url = "https://doi.org/10.56577/ffc-23.120",
    doi = "10.56577/ffc-23.120",
    openalex = "W4297842216",
    pages = "120-123"
}

@article{lozinsky1984late,
    author = "Lozinsky, Richard P. and Hunt, Adrian P. and Wolberg, Donald L. and Lucas, Spencer G.",
    title = "Late Cretaceous (Lancian) dinosaurs from the McRae Formation, Sierra County, New Mexico",
    year = "1984",
    journal = "New Mexico Geology",
    url = "https://doi.org/10.58799/nmg-v6n4.72",
    doi = "10.58799/nmg-v6n4.72",
    number = "4",
    openalex = "W4380563101",
    pages = "72-77",
    volume = "6"
}

Preface Introduction Part I. The Beginning of the Age of Dinosaurs: The Time and the Setting: 1. Historical aspects of the Triassic-Jurassic boundary problem Edwin H. Colbert 2. Fossil plants and the Triassic-Jurassic boundary Sidney Ash Part II. Late Triassic Vertebrate Taxa and Faunas: 3. Thoughts on the origin of the Theropoda Samuel P. Welles 4. Structure and function of the tarsus in the phytosaurs (Reptilia: Archosauria) J. Michael Parrish 5. On the type material of Coelophysis Cope (Saurischis: Theropoda), and a new specimen from the Petrified Forest of Arizona (Late Triassic: Chinle Formation) Kevin Padian 6. The ichnogenus Atreipus and its significance for Triassic biostratigraphy Paul E. Olsen and Donald Baird 7. The limb posture of kannemeyeriid dicynodonts: functional and ecological considerations Laurie R. Walter 8. A new family of mammals from the lower part of the French Rhaetic Denise Sigogneau-Russell, R. M. Frank and J. Hemmerle 9. Vertebrate paleontology of the Dockum Group, western Texas and eastern New Mexico Phillip A. Murry 10. The Late Triassic Dockum vertebrates: their stratigraphic and paleobiogeographic significance Sankar Chatterjee 11. A new vertenrate fauna from the Dockum Formation (Late Triasssic) of eastern New Mexico J. Michael Parrish and Kenneth Carpenter 12. Vertebrate biostratigraphy of the Late Triassic Chinle Formation, Petrified Forest National Park, Arizona: preliminary results R. A. Long and Kevin Padian Part III. Taxa and Trends Across the Triassic-Jurassic Boundary: 13. Triassic and Jurassic fishes: patterns of diversity Amy R. McCune and Bobb Schaeffer 14. Triassic and Early Jurassic turtles Eugene S. Gaffney 15. Archosaur footprints at the terrestrial Triassic-Jurassic transition Hartmut Haubold 16. Herbivorous adaptations of Late Triassic and Early Jurassic dinosaurs Pater M. Galton 17. Masticatory apparatus of the larger herbivores during Late Triassic and early Jurassic times A. W. Crompton and J. Attridge 18. On Triassic and Jurassic mammals William A. Clemens Part IV. Early Jurassic Vertebrate Taxa and Faunas: 19. The early radiation and phylogenetic relationships of the Jurassic sauropod dinosaurs, based on vertebral anatomy Jose F. Bonaparte 20. Earliest records of Batrachopus from the southwestern United States, and a revision of some early Mesozoic crocodylomorph ichnogenera Paul E. Olsen and Kevin Padian 21. A brief introduction to the Lower Lufeng saurischian fauna (Lower Jurassic: Lufeng, Yunnan, People's Republic of China) A. L. Sun and K. H. Cui 22. Relationships and biostratigraphic significance of the Tritylodontidae (Synapsida) from the Kayenta Formation of northeastern Arizona Hans Dieter Sues 23. Vertebrate biostrarigraphy of the Glen canyon Group in northern Arizona James M. Clark and David E. Fastovsky Part V. Macroevolutionary Patterns of the Triassic-Jurassic Transition: 24. The Late Triassic tetrapod extinction events Michael J. Benton 25. Correlation of continental Late Triassic and Early Jurassic sediments, and patterns of the Triassic-Jurassic tetrapod transition Paul E. Olsen and Hans-Dieter Sues 26. Terrestrial vertebrate faunal succession during the Triassic J. M. Zawiskie Summary and prospectus Taxonomic index Ichnotaxonomic index.

@book{openalexw606525048,
    author = "Padian, Kevin",
    title = "The Beginning of the age of dinosaurs: faunal change across the Triassic-Jurassic boundary",
    year = "1986",
    booktitle = "Cambridge University Press eBooks",
    abstract = "Preface Introduction Part I. The Beginning of the Age of Dinosaurs: The Time and the Setting: 1. Historical aspects of the Triassic-Jurassic boundary problem Edwin H. Colbert 2. Fossil plants and the Triassic-Jurassic boundary Sidney Ash Part II. Late Triassic Vertebrate Taxa and Faunas: 3. Thoughts on the origin of the Theropoda Samuel P. Welles 4. Structure and function of the tarsus in the phytosaurs (Reptilia: Archosauria) J. Michael Parrish 5. On the type material of Coelophysis Cope (Saurischis: Theropoda), and a new specimen from the Petrified Forest of Arizona (Late Triassic: Chinle Formation) Kevin Padian 6. The ichnogenus Atreipus and its significance for Triassic biostratigraphy Paul E. Olsen and Donald Baird 7. The limb posture of kannemeyeriid dicynodonts: functional and ecological considerations Laurie R. Walter 8. A new family of mammals from the lower part of the French Rhaetic Denise Sigogneau-Russell, R. M. Frank and J. Hemmerle 9. Vertebrate paleontology of the Dockum Group, western Texas and eastern New Mexico Phillip A. Murry 10. The Late Triassic Dockum vertebrates: their stratigraphic and paleobiogeographic significance Sankar Chatterjee 11. A new vertenrate fauna from the Dockum Formation (Late Triasssic) of eastern New Mexico J. Michael Parrish and Kenneth Carpenter 12. Vertebrate biostratigraphy of the Late Triassic Chinle Formation, Petrified Forest National Park, Arizona: preliminary results R. A. Long and Kevin Padian Part III. Taxa and Trends Across the Triassic-Jurassic Boundary: 13. Triassic and Jurassic fishes: patterns of diversity Amy R. McCune and Bobb Schaeffer 14. Triassic and Early Jurassic turtles Eugene S. Gaffney 15. Archosaur footprints at the terrestrial Triassic-Jurassic transition Hartmut Haubold 16. Herbivorous adaptations of Late Triassic and Early Jurassic dinosaurs Pater M. Galton 17. Masticatory apparatus of the larger herbivores during Late Triassic and early Jurassic times A. W. Crompton and J. Attridge 18. On Triassic and Jurassic mammals William A. Clemens Part IV. Early Jurassic Vertebrate Taxa and Faunas: 19. The early radiation and phylogenetic relationships of the Jurassic sauropod dinosaurs, based on vertebral anatomy Jose F. Bonaparte 20. Earliest records of Batrachopus from the southwestern United States, and a revision of some early Mesozoic crocodylomorph ichnogenera Paul E. Olsen and Kevin Padian 21. A brief introduction to the Lower Lufeng saurischian fauna (Lower Jurassic: Lufeng, Yunnan, People's Republic of China) A. L. Sun and K. H. Cui 22. Relationships and biostratigraphic significance of the Tritylodontidae (Synapsida) from the Kayenta Formation of northeastern Arizona Hans Dieter Sues 23. Vertebrate biostrarigraphy of the Glen canyon Group in northern Arizona James M. Clark and David E. Fastovsky Part V. Macroevolutionary Patterns of the Triassic-Jurassic Transition: 24. The Late Triassic tetrapod extinction events Michael J. Benton 25. Correlation of continental Late Triassic and Early Jurassic sediments, and patterns of the Triassic-Jurassic tetrapod transition Paul E. Olsen and Hans-Dieter Sues 26. Terrestrial vertebrate faunal succession during the Triassic J. M. Zawiskie Summary and prospectus Taxonomic index Ichnotaxonomic index.",
    url = "https://openalex.org/W606525048",
    openalex = "W606525048"
}

@book{parrish1986a1,
    author = "Parrish, J. M. and Carpenter, K",
    title = "A New Vertebrate Fauna from the Dockum Formation (Late Triassic) of Eastern New Mexico, in Padian, K., ed., The Beginning of the Age of Dinosaurs",
    year = "1986",
    publisher = "Cambridge, Cambridge University Press, p. 152-160",
    note = "talkorigins\_source = {true}; raw\_reference = {Parrish, J. M., and Carpenter, K., 1986, A New Vertebrate Fauna from the Dockum Formation (Late Triassic) of Eastern New Mexico, in Padian, K., ed., The Beginning of the Age of Dinosaurs: Cambridge, Cambridge University Press, p. 152-160.}"
}

The record of life on land has been a principal concern of historical biology not only because of our fascination with our own past (and with giants, dragons, and other ancient monsters) but because of special opportunities and challenges for development of methods, principles, and concepts of explanation. The Beginning of the Age of Dinosaurs treats an intriguing phase of that history, one that included the first appearance of dinosaurs, and mammals, the extinction or near extinction of many clades of vertebrates, and extensive changes in plant associations. Further, the patterns of change (and of stasis) raise general questions about macroecologic and macroevolutionary processes and factors and even about the roles of chance and determination in biological history. Although the book was published initially in 1986 (and was based on a 1984 symposium sponsored by the Society of Vertebrate Paleontologists), its content remains current and its release in paperback form (for $34.50 rather than $75.00 for the hardcover version) justifies a review even at this late date. The Introduction and the Summary and Prospectus, written by the editor, Kevin Padian, demonstrate the significance of the interval from mid-Triassic to early Jurassic-particularly for vertebrates on land. Advanced mammal-like reptiles (therapsids) dominate lower Triassic assemblages in abundance, taxonomic diversity, and ecological variety; non-therapsids (mostly archosaurs) are rare elements and apparently of little ecological importance. In upper Triassic and lower Jurassic assemblages the situation is reversed, therapsids rare with limited diversity and variety but archosaurs abundant, diverse and varied. The archosaur expansion starts in middle of the succession; pterodactyls, crocodylomorphs, and dinosaurs appear (as archosaur subclades) in approximate coincidence with a marked decline in therapsids. Mammals (at least 3 subclades) occur along with two other subclades of very mammal-like therapsids very close to the top. In the upper Triassic two relatively sharp breaks in faunal composition appear, one relatively low, in the top of the Carnian and base of the Norian stages (around 225 Ma), and one higher, at the top of the Norian (around 215 Ma). These breaks, if real and not a consequence of miscorrelations or gaps in sampling, suggest high rates of taxonomic extinction and origination and have been interpreted as intervals of catastrophic extinction. These changes coincide more or less with some in the flora (except that the latter seem continuous rather than stepped) and thus with overall changes in terrestrial ecosystems. Radically different explanations have been offered for these patterns, at one extreme a deterministic argument from the competitive superiority of dinosaurs to the other, an opportunistic one based on chance differences in survival through episodes of mass extinction. This book can be viewed (and reviewed) as an extended example of analysis and interpretation in historical biology. The concerns of the discipline are twofold, chronicle and narrative (the concepts those of O'Hara, 1988). Chronicle comprises when, what, and where; narrative, how. A chronicle extends of course beyond description and chronologic ordering of fossils to paleobiogeographic, paleoecologic, and phylogenetic reconstructions. The latter derive from patterns in form and occurrence of fossils as analyzed in terms of taphonomic, constructional, functional, and phylogenetic processes and factors (viz Seilacher, 1970) and of stratigraphic and geographic distribution. Each reconstruction represents a particular state, and stratigraphic analysis arranges these reconstructions into a chronicle. Narrative, in contrast, involves explanation of the patterns (temporal, geographic, ecologic and phyletic) in the chronicle by a sequence of biological and physical circumstances and by evolutionary processes and factors (genetic, phylogenetic, and ecological). Of the 26 papers in this volume, 24 focus primarily on the chronicle and are dominated by consideration of what-when, i.e., the stratigraphic distribution of various groups of fossils, and of what-how, i.e., the phylogenetic and functional analyses. Among those in the what-when group are papers by Colbert on historical aspects of upper Triassic-lower Jurassic stratigraphy, by Ash on fossil plants, by Olsen and Baird on the ichnogenus Atreipus, by Chatterjee and by Parrish and Carpenter on vertebrates of the Dockum Group (Texas and New Mexico), and by Long and Padian on biostratigraphy of the Chinle Formation (Arizona). Also best included here are the studies by McCune and Schaeffer on Triassic and Jurassic fishes, Gaffney on turtles, Clemens on mammals, Olson and Padian on crocodylomorph ichnogenera, Sun and Cui on saurishians from the lower Lufeng (China), Clark and Fastovsky on the vertebrates of the Glen Canyon Group (Arizona), Haubold on archosaur trackways, Sigogneau-Russell, Frank, and Hemmerle on a new family of Triassic

@article{doi1023073514751,
    author = "Beerbower, Richard and Padian, Kevin",
    title = "The Beginning of the Age of Dinosaurs",
    year = "1989",
    journal = "Palaios",
    abstract = "The record of life on land has been a principal concern of historical biology not only because of our fascination with our own past (and with giants, dragons, and other ancient monsters) but because of special opportunities and challenges for development of methods, principles, and concepts of explanation. The Beginning of the Age of Dinosaurs treats an intriguing phase of that history, one that included the first appearance of dinosaurs, and mammals, the extinction or near extinction of many clades of vertebrates, and extensive changes in plant associations. Further, the patterns of change (and of stasis) raise general questions about macroecologic and macroevolutionary processes and factors and even about the roles of chance and determination in biological history. Although the book was published initially in 1986 (and was based on a 1984 symposium sponsored by the Society of Vertebrate Paleontologists), its content remains current and its release in paperback form (for $34.50 rather than $75.00 for the hardcover version) justifies a review even at this late date. The Introduction and the Summary and Prospectus, written by the editor, Kevin Padian, demonstrate the significance of the interval from mid-Triassic to early Jurassic-particularly for vertebrates on land. Advanced mammal-like reptiles (therapsids) dominate lower Triassic assemblages in abundance, taxonomic diversity, and ecological variety; non-therapsids (mostly archosaurs) are rare elements and apparently of little ecological importance. In upper Triassic and lower Jurassic assemblages the situation is reversed, therapsids rare with limited diversity and variety but archosaurs abundant, diverse and varied. The archosaur expansion starts in middle of the succession; pterodactyls, crocodylomorphs, and dinosaurs appear (as archosaur subclades) in approximate coincidence with a marked decline in therapsids. Mammals (at least 3 subclades) occur along with two other subclades of very mammal-like therapsids very close to the top. In the upper Triassic two relatively sharp breaks in faunal composition appear, one relatively low, in the top of the Carnian and base of the Norian stages (around 225 Ma), and one higher, at the top of the Norian (around 215 Ma). These breaks, if real and not a consequence of miscorrelations or gaps in sampling, suggest high rates of taxonomic extinction and origination and have been interpreted as intervals of catastrophic extinction. These changes coincide more or less with some in the flora (except that the latter seem continuous rather than stepped) and thus with overall changes in terrestrial ecosystems. Radically different explanations have been offered for these patterns, at one extreme a deterministic argument from the competitive superiority of dinosaurs to the other, an opportunistic one based on chance differences in survival through episodes of mass extinction. This book can be viewed (and reviewed) as an extended example of analysis and interpretation in historical biology. The concerns of the discipline are twofold, chronicle and narrative (the concepts those of O'Hara, 1988). Chronicle comprises when, what, and where; narrative, how. A chronicle extends of course beyond description and chronologic ordering of fossils to paleobiogeographic, paleoecologic, and phylogenetic reconstructions. The latter derive from patterns in form and occurrence of fossils as analyzed in terms of taphonomic, constructional, functional, and phylogenetic processes and factors (viz Seilacher, 1970) and of stratigraphic and geographic distribution. Each reconstruction represents a particular state, and stratigraphic analysis arranges these reconstructions into a chronicle. Narrative, in contrast, involves explanation of the patterns (temporal, geographic, ecologic and phyletic) in the chronicle by a sequence of biological and physical circumstances and by evolutionary processes and factors (genetic, phylogenetic, and ecological). Of the 26 papers in this volume, 24 focus primarily on the chronicle and are dominated by consideration of what-when, i.e., the stratigraphic distribution of various groups of fossils, and of what-how, i.e., the phylogenetic and functional analyses. Among those in the what-when group are papers by Colbert on historical aspects of upper Triassic-lower Jurassic stratigraphy, by Ash on fossil plants, by Olsen and Baird on the ichnogenus Atreipus, by Chatterjee and by Parrish and Carpenter on vertebrates of the Dockum Group (Texas and New Mexico), and by Long and Padian on biostratigraphy of the Chinle Formation (Arizona). Also best included here are the studies by McCune and Schaeffer on Triassic and Jurassic fishes, Gaffney on turtles, Clemens on mammals, Olson and Padian on crocodylomorph ichnogenera, Sun and Cui on saurishians from the lower Lufeng (China), Clark and Fastovsky on the vertebrates of the Glen Canyon Group (Arizona), Haubold on archosaur trackways, Sigogneau-Russell, Frank, and Hemmerle on a new family of Triassic",
    url = "https://doi.org/10.2307/3514751",
    doi = "10.2307/3514751",
    openalex = "W2320472492",
    references = "doi101017cbo9780511608551, doi1023072807146, doi1023072992272"
}

@article{lucas1990late,
    author = "Lucas, Spencer G. and Basabilvazo, George and Lawton, Timothy F.",
    title = "Late cretaceous dinosaurs from the ringbone formation, southwestern New Mexico, U.S.A.",
    year = "1990",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/s0195-6671(05)80045-x",
    doi = "10.1016/s0195-6671(05)80045-x",
    number = "4",
    openalex = "W2018184613",
    pages = "343-349",
    volume = "11"
}

40 Ar/ 39 Ar dating of sanidine from a bentonite interbedded in the Ischigualasto Formation of northwestern Argentina yielded a plateau age of 227.8 ± 0.3 million years ago. This middle Carnian age is a direct calibration of the Ischigualasto tetrapod assemblage, which includes some of the best known early dinosaurs. This age shifts last appearances of Ischigualasto taxa back into the middle Carnian, diminishing the magnitude of the proposed late Carnian tetrapod extinction event. By 228 million years ago, the major dinosaurian lineages were established, and theropods were already important constituents of the carnivorous tetrapod guild in the Ischigualasto—Villa Unión Basin. Dinosaurs as a whole remained minor components of tetrapod faunas for at least another 10 million years.

@article{doi101126science2605109794,
    author = "Rogers, Raymond R. and Swisher, Carl C. and Sereno, Paul C. and Monetta, Alfredo M. and Forster, Catherine A. and Martínez, Ricardo N.",
    title = "The Ischigualasto Tetrapod Assemblage (Late Triassic, Argentina) and 40 Ar/ 39 Ar Dating of Dinosaur Origins",
    year = "1993",
    journal = "Science",
    abstract = "40 Ar/ 39 Ar dating of sanidine from a bentonite interbedded in the Ischigualasto Formation of northwestern Argentina yielded a plateau age of 227.8 ± 0.3 million years ago. This middle Carnian age is a direct calibration of the Ischigualasto tetrapod assemblage, which includes some of the best known early dinosaurs. This age shifts last appearances of Ischigualasto taxa back into the middle Carnian, diminishing the magnitude of the proposed late Carnian tetrapod extinction event. By 228 million years ago, the major dinosaurian lineages were established, and theropods were already important constituents of the carnivorous tetrapod guild in the Ischigualasto—Villa Unión Basin. Dinosaurs as a whole remained minor components of tetrapod faunas for at least another 10 million years.",
    url = "https://doi.org/10.1126/science.260.5109.794",
    doi = "10.1126/science.260.5109.794",
    openalex = "W2017250743",
    references = "doi101007bf01134434, doi101111j155856461971tb01922x, doi1023073514444, doi1023073514695, doi105962bhlpart22965, openalexw1574544995"
}

Fragmentary bones and teeth of three Late Cretaceous dinosaur taxa occur along both sides of the Georgia-Alabama border, in the extreme southeastern Coastal Plain Province. The localities lie in the middle and upper Blufftown Formation, in nearshore marine deposits. Exogyra ssp. and calcareous nannofossils give a late Santonian through mid-Campanian age range. Taxa determined are: Hadrosauridae, genus and species indeterminate; Ornithomimidae, genus and species indeterminate; and Albertosaurus? sp.

@article{schwimmer1993late,
    author = "Schwimmer, David R. and Williams, G. Dent and Dobie, James L. and Siesser, William G.",
    title = "Late Cretaceous dinosaurs from the Blufftown Formation in western Georgia and eastern Alabama",
    year = "1993",
    journal = "Journal of Paleontology",
    abstract = "Fragmentary bones and teeth of three Late Cretaceous dinosaur taxa occur along both sides of the Georgia-Alabama border, in the extreme southeastern Coastal Plain Province. The localities lie in the middle and upper Blufftown Formation, in nearshore marine deposits. Exogyra ssp. and calcareous nannofossils give a late Santonian through mid-Campanian age range. Taxa determined are: Hadrosauridae, genus and species indeterminate; Ornithomimidae, genus and species indeterminate; and Albertosaurus? sp.",
    url = "https://doi.org/10.1017/s0022336000032212",
    doi = "10.1017/s0022336000032212",
    number = "2",
    openalex = "W2460649140",
    pages = "288-296",
    volume = "67",
    references = "doi101130spe40p1, doi101139e72031, doi1023071005355, doi102475ajss321125417, doi102475ajss32313381, doi102475ajss33922981, doi105281zenodo814935, doi105962bhltitle39830, doi107208chicago97802268816830010001, openalexw1999719961"
}

A diverse assemblage of fossil vertebrates has been discovered in the Fleming Fjord Formation (Malmros Klint and Ørsted Dal Members) in East Greenland between latitudes 71°15'N and 71°50'N. The fauna includes several species of mammals as well as prosauropod (Plateosaurus) and theropod dinosaurs, turtles (cf. Proganochelys), pterosaurs, aetosaurs (Aetosaurus ferratus, Paratypothorax andressi), labyrinthodont amphibians (Gerrothorax, Cyclotosaurus and possibly other taxa) and fishes (including sharks, actinopterygians, coelacanths and lungfish). The association of the genera Aetosaurus, Plateosaurus, Proganochelys, Cyclotosaurus and Gerrothorax is shared with well known European Norian faunas, and confirms the paleogeographic proximity of Greenland and Europe during Late Triassic time. On this evidence, the Ørsted Dal Member may be estimated to be at least as old as mid-Norian, but a comparable age estimate for the underlying Malmros Klint Member cannot be made on the basis of the fauna as presently known. The Malmros Klint Member is characterized by composite cyclicity with four orders of cycles involving silt-rich, ephemeral lake or playa-mudflat systems, loess beds, wave-reworked sand flats, flat pebble conglomerates and paleosols. The rhythmicity and thickness ratios of the beds are evidence that depositional conditions were controlled by Milankovitch cycles, with climatic conditions varying from humid, to dry with seasonal rainfall, to arid. Cyclical sedimentary conditions and climatic fluctuations appear to have continued during the subsequent deposition of the overlying Ørsted Dal Member.

@article{doi107146moggeosciv32i140904,
    author = "Jenkins, Farish A. and Shubin, Neil H. and Amaral, William W. and Gatesy, Stephen M. and Schaff, Charles R. and Clemmensen, Lars B. and Downs, William R. and Davidson, Amy R. and Bonde, Niels and Osbæck, Frank",
    title = "Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland",
    year = "1994",
    journal = "Meddelelser om Grønland Geoscience",
    abstract = "A diverse assemblage of fossil vertebrates has been discovered in the Fleming Fjord Formation (Malmros Klint and Ørsted Dal Members) in East Greenland between latitudes 71°15'N and 71°50'N. The fauna includes several species of mammals as well as prosauropod (Plateosaurus) and theropod dinosaurs, turtles (cf. Proganochelys), pterosaurs, aetosaurs (Aetosaurus ferratus, Paratypothorax andressi), labyrinthodont amphibians (Gerrothorax, Cyclotosaurus and possibly other taxa) and fishes (including sharks, actinopterygians, coelacanths and lungfish). The association of the genera Aetosaurus, Plateosaurus, Proganochelys, Cyclotosaurus and Gerrothorax is shared with well known European Norian faunas, and confirms the paleogeographic proximity of Greenland and Europe during Late Triassic time. On this evidence, the Ørsted Dal Member may be estimated to be at least as old as mid-Norian, but a comparable age estimate for the underlying Malmros Klint Member cannot be made on the basis of the fauna as presently known. The Malmros Klint Member is characterized by composite cyclicity with four orders of cycles involving silt-rich, ephemeral lake or playa-mudflat systems, loess beds, wave-reworked sand flats, flat pebble conglomerates and paleosols. The rhythmicity and thickness ratios of the beds are evidence that depositional conditions were controlled by Milankovitch cycles, with climatic conditions varying from humid, to dry with seasonal rainfall, to arid. Cyclical sedimentary conditions and climatic fluctuations appear to have continued during the subsequent deposition of the overlying Ørsted Dal Member.",
    url = "https://doi.org/10.7146/moggeosci.v32i.140904",
    doi = "10.7146/moggeosci.v32i.140904",
    openalex = "W4389136907",
    references = "doi1010160031018279901123, doi101017s0094837300010575, doi101126science2344778842, doi101126science3616622, doi1023072412728, doi1023072421869, doi1023073514751, doi1034194bullgguv1396681, openalexw2242116350, openalexw3140893762"
}

Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well-developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.

@article{doi101017s0022336000038427,
    author = "Lehman, Thomas M.",
    title = "A horned dinosaur from the El Picacho Formation of west Texas, and review of ceratopsian dinosaurs from the American southwest",
    year = "1996",
    journal = "Journal of Paleontology",
    abstract = "Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well-developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.",
    url = "https://doi.org/10.1017/s0022336000038427",
    doi = "10.1017/s0022336000038427",
    openalex = "W2492024881",
    references = "lozinsky1984late, openalexw2772929664"
}

ABSTRACT Skin impressions from the tail region of an indeterminate hadrosaur recently excavated from the Upper Cretaceous Ringbone Formation, southwest New Mexico represent the first known dinosaur specimen from New Mexico with impressions of the integument preserved in association with skeletal remains. The mid- to distal-caudal region is represented by 20 articulated centra, other disarticulated centra, a single chevron, ossified tendons and fragmentary bone, including poorly preserved neural spines. The skin impressions are preserved in negative and positive relief between two very fine-grained sandstone beds, interpreted as part of a fluvio-lacustrine facies package. The impression surface is directly below the ossified tendons, and 2.5 m from the articulated vertebral column. The skin impressions are six discrete patches characterized by predominantly apical, circular to ovate tubercles. Measurements of the long and short axes of individual tubercles demonstrate that a distribution of relatively homogenous tubercle sizes occur along the tail section. The tubercles range from 3 to 12 mm and 10 to 16 mm on the short and long axes, respectively. All tubercles examined are ornamented with radiating ridges and grooves that converge at their apex. Presently, the material cannot be identified below the level of Hadrosauridae; however, a comparison of tubercle size, shape and ornamentation described previously from hadrosaur skin impressions indicates the integument morphology of the Ringbone hadrosaur has some similarities to that of the gryposaurs. In general, the complexity of the radial sculpturing, specifically the number of ridges and rugosity, increases with increasing tubercle size. This specific type of ornamentation is not known from modern reptiles or birds; however, the tubercular morphology is similar to that of the lizard Heloderma. Although it is impossible to determine whether the ridges and grooves may have had a physiologic function, these features would increase the surface area of the skin, and therefore may have afforded more efficient heat exchange across the skin, or possibly provided added resistance to tearing and puncturing.

@article{doi10108002724634199810011102,
    author = "Anderson, Brian G. and Lucas, Spencer G. and Barrick, Reese E. and Heckert, Andrew B. and Basabilvazo, G.",
    title = "Dinosaur skin impressions and associated skeletal remains from the upper Campanian of southwestern New Mexico: new data on the integument morphology of hadrosaurs",
    year = "1998",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT Skin impressions from the tail region of an indeterminate hadrosaur recently excavated from the Upper Cretaceous Ringbone Formation, southwest New Mexico represent the first known dinosaur specimen from New Mexico with impressions of the integument preserved in association with skeletal remains. The mid- to distal-caudal region is represented by 20 articulated centra, other disarticulated centra, a single chevron, ossified tendons and fragmentary bone, including poorly preserved neural spines. The skin impressions are preserved in negative and positive relief between two very fine-grained sandstone beds, interpreted as part of a fluvio-lacustrine facies package. The impression surface is directly below the ossified tendons, and 2.5 m from the articulated vertebral column. The skin impressions are six discrete patches characterized by predominantly apical, circular to ovate tubercles. Measurements of the long and short axes of individual tubercles demonstrate that a distribution of relatively homogenous tubercle sizes occur along the tail section. The tubercles range from 3 to 12 mm and 10 to 16 mm on the short and long axes, respectively. All tubercles examined are ornamented with radiating ridges and grooves that converge at their apex. Presently, the material cannot be identified below the level of Hadrosauridae; however, a comparison of tubercle size, shape and ornamentation described previously from hadrosaur skin impressions indicates the integument morphology of the Ringbone hadrosaur has some similarities to that of the gryposaurs. In general, the complexity of the radial sculpturing, specifically the number of ridges and rugosity, increases with increasing tubercle size. This specific type of ornamentation is not known from modern reptiles or birds; however, the tubercular morphology is similar to that of the lizard Heloderma. Although it is impossible to determine whether the ridges and grooves may have had a physiologic function, these features would increase the surface area of the skin, and therefore may have afforded more efficient heat exchange across the skin, or possibly provided added resistance to tearing and puncturing.",
    url = "https://doi.org/10.1080/02724634.1998.10011102",
    doi = "10.1080/02724634.1998.10011102",
    openalex = "W2053213212",
    references = "lucas1990late"
}

The first formal report of Tertiary portunid crabs for Mexico is based on two new species, Portunus atecuicitli and Necronectes tajinensis, from the middle Miocene beds of the Tuxpan Formation in Veracruz, east-central Mexico. Associated crustacean remains include fragments of calappid fingers, calappid carapace fragments possibly assignable to Matuta Fabricius, and callianassid hands. Low tolerance to osmotic variations of recent species of Portunus confirms paleoenvironmental interpretations for shallow, euryhaline, tropical waters during deposition of the Tuxpan Formation.

@article{vega1999a,
    author = "Vega, Francisco J. and Feldmann, Rodney M. and Villalobos-Hiriart, José Luis and Gío-Argíez, Raúl",
    title = "A new decapod fauna from the Miocene Tuxpan Formation, eastern Mexico",
    year = "1999",
    journal = "Journal of Paleontology",
    abstract = "The first formal report of Tertiary portunid crabs for Mexico is based on two new species, Portunus atecuicitli and Necronectes tajinensis, from the middle Miocene beds of the Tuxpan Formation in Veracruz, east-central Mexico. Associated crustacean remains include fragments of calappid fingers, calappid carapace fragments possibly assignable to Matuta Fabricius, and callianassid hands. Low tolerance to osmotic variations of recent species of Portunus confirms paleoenvironmental interpretations for shallow, euryhaline, tropical waters during deposition of the Tuxpan Formation.",
    url = "https://doi.org/10.1017/s0022336000027931",
    doi = "10.1017/s0022336000027931",
    number = "3",
    openalex = "W2181967431",
    pages = "407-413",
    volume = "73",
    references = "doi1023071352125, doi105281zenodo16563925, doi105479si03629236152i, doi105860choice272711, doi105962bhltitle106607, doi105962bhltitle12297, doi105962bhltitle15764, openalexw2403805483, openalexw2787496728, openalexw602415728"
}

(2000). Alamosaurus (Dinosauria: Sauropoda) from the late Campanian of New Mexico and its significance. Journal of Vertebrate Paleontology: Vol. 20, No. 2, pp. 400-403.

@article{doi1016710272463420000200400adsftl20co2,
    author = "Sullivan, Robert M. and Lucas, Spencer G.",
    title = "Alamosaurus (Dinosauria: Sauropoda) from the late Campanian of New Mexico and its significance",
    year = "2000",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "(2000). Alamosaurus (Dinosauria: Sauropoda) from the late Campanian of New Mexico and its significance. Journal of Vertebrate Paleontology: Vol. 20, No. 2, pp. 400-403.",
    url = "https://doi.org/10.1671/0272-4634(2000)020[0400:adsftl]2.0.co;2",
    doi = "10.1671/0272-4634(2000)020[0400:adsftl]2.0.co;2",
    openalex = "W2172591754",
    references = "lucas1990late"
}

Abstract An accumulation of skeletons of the pre-dinosaur Silesaurus opolensis, gen. et sp. nov. is described from the Keuper (Late Triassic) claystone of Krasiejów in southern Poland. The strata are correlated with the late Carnian Lehrberg Beds and contain a diverse assemblage of tetrapods, including the phytosaur Paleorhinus, which in other regions of the world co-occurs with the oldest dinosaurs. A narrow pelvis with long pubes and the extensive development of laminae in the cervical vertebrae place S. opolensis close to the origin of the clade Dinosauria above Pseudolagosuchus, which agrees with its geological age. Among the advanced characters is the beak on the dentaries, and the relatively low tooth count. The teeth have low crowns and wear facets, which are suggestive of herbivory. The elongate, but weak, front limbs are probably a derived feature.

@article{doi101671a1097,
    author = "Dzik, Jerzy",
    title = "A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland",
    year = "2003",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "Abstract An accumulation of skeletons of the pre-dinosaur Silesaurus opolensis, gen. et sp. nov. is described from the Keuper (Late Triassic) claystone of Krasiejów in southern Poland. The strata are correlated with the late Carnian Lehrberg Beds and contain a diverse assemblage of tetrapods, including the phytosaur Paleorhinus, which in other regions of the world co-occurs with the oldest dinosaurs. A narrow pelvis with long pubes and the extensive development of laminae in the cervical vertebrae place S. opolensis close to the origin of the clade Dinosauria above Pseudolagosuchus, which agrees with its geological age. Among the advanced characters is the beak on the dentaries, and the relatively low tooth count. The teeth have low crowns and wear facets, which are suggestive of herbivory. The elongate, but weak, front limbs are probably a derived feature.",
    url = "https://doi.org/10.1671/a1097",
    doi = "10.1671/a1097",
    openalex = "W2101751293",
    references = "doi101016s001669959880123x, doi101016s0031018298001175, doi101038361064a0, doi10108002724634199110011386, doi10108002724634199110011426, doi10108002724634199910011178, doi101098rstb19990489, doi10718895fylantbak30809522, openalexw2310875238, openalexw2788234611, openalexw606525048, openalexw616953834, sereno1997the"
}

ABSTRACT The discovery of a new genus and species of tyrannosauroid from the Demopolis Formation (middle Campanian) of Alabama increases the known diversity of the clade, although it does not elucidate the place of initial dispersal. This subadult tyrannosauroid is the most complete non-avian theropod collected and described from the Cretaceous of eastern North America. In contrast to tyrannosaurids, the new taxon possesses several plesiomorphic characters, including lacrimals that lack a distinct peaked cornual process, and a dorsoventrally shallow horizontal ramus of the maxilla. Autapomorphies include a wide jugal process of the ectopterygoid, a caudal pneumatic foramen of the palatine that pierces the rostral half of the vomeropterygoid process of the bone, an articular surface for the lacrimal on the palatine that is distally positioned on the dorsolateral process, and pedal unguals that have a distinct proximodorsal lip over the articular surface. Cladistic analysis indicates the new taxon is a basal tyrannosauroid and its presence in eastern North America suggests that the recent common ancestor of Tyrannosauridae probably evolved following the transgression of the Western Interior Seaway. Cladistic analysis indicates that Dryptosaurus aquilunguis is also a basal tyrannosauroid but is less derived than the new genus.

@article{doi1016710272463420050250119angaso20co2,
    author = "Carr, Thomas D. and Williamson, Thomas E. and Schwimmer, David R.",
    title = "A new genus and species of tyrannosauroid from the Late Cretaceous (Middle Campanian) Demopolis Formation of Alabama",
    year = "2005",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "ABSTRACT The discovery of a new genus and species of tyrannosauroid from the Demopolis Formation (middle Campanian) of Alabama increases the known diversity of the clade, although it does not elucidate the place of initial dispersal. This subadult tyrannosauroid is the most complete non-avian theropod collected and described from the Cretaceous of eastern North America. In contrast to tyrannosaurids, the new taxon possesses several plesiomorphic characters, including lacrimals that lack a distinct peaked cornual process, and a dorsoventrally shallow horizontal ramus of the maxilla. Autapomorphies include a wide jugal process of the ectopterygoid, a caudal pneumatic foramen of the palatine that pierces the rostral half of the vomeropterygoid process of the bone, an articular surface for the lacrimal on the palatine that is distally positioned on the dorsolateral process, and pedal unguals that have a distinct proximodorsal lip over the articular surface. Cladistic analysis indicates the new taxon is a basal tyrannosauroid and its presence in eastern North America suggests that the recent common ancestor of Tyrannosauridae probably evolved following the transgression of the Western Interior Seaway. Cladistic analysis indicates that Dryptosaurus aquilunguis is also a basal tyrannosauroid but is less derived than the new genus.",
    url = "https://doi.org/10.1671/0272-4634(2005)025[0119:angaso]2.0.co;2",
    doi = "10.1671/0272-4634(2005)025[0119:angaso]2.0.co;2",
    openalex = "W2179448599",
    references = "doi10108002724634199710011003, schwimmer1993late"
}

Synopsis The North American Triassic dinosaur record has been repeatedly cited as one of the most complete early dinosaur assemblages. The discovery of Silesaurus from Poland and the recognition that Herrerasaurus and Eoraptor may not be theropods have forced a re‐evaluation of saurischian and theropod synapomorphies. Here, we re‐evaluate each purported Triassic dinosaur from North America on a specimen by specimen basis using an apomorphy‐based approach. We attempt to assign specimens to the most exclusive taxon possible. Our revision of purported Late Triassic dinosaur material from North America indicates that dinosaurs were rarer and less diverse in these strata than previously thought. This analysis concludes that non‐dinosaurian dinosauriforms were present in North America in the Late Triassic. Most of the proposed theropod specimens are fragmentary and/or indistinguishable from corresponding elements in the only well‐known Triassic theropod of North America, Coelophysis bauri. No Triassic material from North America can be assigned to Sauropodomorpha, because none of the purported ‘prosauropod’ material is diagnostic. Recent discovery of the skull and skeleton of Revueltosaurus callenderi from Arizona shows that it is a pseudosuchian archosaur, not an ornithischian dinosaur. As a result, other purported North American ornithischian teeth cannot be assigned to the Ornithischia and therefore, there are no confirmed North American Triassic ornithischians. Non‐tetanuran theropods and possible basal saurischians are the only identifiable dinosaurs recognised in North America until the beginning of the Jurassic Period.

@article{doi101017s1477201907002040,
    author = "Nesbitt, Sterling J. and Irmis, Randall B. and Parker, William G.",
    title = "A critical re‐evaluation of the Late Triassic dinosaur taxa of North America",
    year = "2007",
    journal = "Journal of Systematic Palaeontology",
    abstract = "Synopsis The North American Triassic dinosaur record has been repeatedly cited as one of the most complete early dinosaur assemblages. The discovery of Silesaurus from Poland and the recognition that Herrerasaurus and Eoraptor may not be theropods have forced a re‐evaluation of saurischian and theropod synapomorphies. Here, we re‐evaluate each purported Triassic dinosaur from North America on a specimen by specimen basis using an apomorphy‐based approach. We attempt to assign specimens to the most exclusive taxon possible. Our revision of purported Late Triassic dinosaur material from North America indicates that dinosaurs were rarer and less diverse in these strata than previously thought. This analysis concludes that non‐dinosaurian dinosauriforms were present in North America in the Late Triassic. Most of the proposed theropod specimens are fragmentary and/or indistinguishable from corresponding elements in the only well‐known Triassic theropod of North America, Coelophysis bauri. No Triassic material from North America can be assigned to Sauropodomorpha, because none of the purported ‘prosauropod’ material is diagnostic. Recent discovery of the skull and skeleton of Revueltosaurus callenderi from Arizona shows that it is a pseudosuchian archosaur, not an ornithischian dinosaur. As a result, other purported North American ornithischian teeth cannot be assigned to the Ornithischia and therefore, there are no confirmed North American Triassic ornithischians. Non‐tetanuran theropods and possible basal saurischians are the only identifiable dinosaurs recognised in North America until the beginning of the Jurassic Period.",
    url = "https://doi.org/10.1017/s1477201907002040",
    doi = "10.1017/s1477201907002040",
    openalex = "W2002503490",
    references = "chatterjee2013a, crossref1976allosaurus, crossref1998encyclopedia, doi101007bf00377897, doi101016s001669959880123x, doi101017cbo9780511608377010, doi10108002724634199110011426, doi10108002724634199710011027, doi10108002724634199810011086, doi10108002724634199910011124, doi10108002724634199910011178, doi101093auk12041206, doi101111j150239311985tb00690x, doi101126science2562999, doi101126science28454232137, doi1023071441916, doi1034191b109, doi105281zenodo16171435, doi105860choice353642, doi105962bhltitle54054, doi10718895fylantbak30806570, lucas2001theropod, openalexw2912219260, openalexw3210282143"
}

It has generally been thought that the first dinosaurs quickly replaced more archaic Late Triassic faunas, either by outcompeting them or when the more archaic faunas suddenly became extinct. Fossils from the Hayden Quarry, in the Upper Triassic Chinle Formation of New Mexico, and an analysis of other regional Upper Triassic assemblages instead imply that the transition was gradual. Some dinosaur relatives preserved in this Chinle assemblage belong to groups previously known only from the Middle and lowermost Upper Triassic outside North America. Thus, the transition may have extended for 15 to 20 million years and was probably diachronous at different paleolatitudes.

@article{doi101126science1143325,
    author = "Irmis, Randall B. and Nesbitt, Sterling J. and Padian, Kevin and Smith, Nathan D. and Turner, Alan H. and Woody, Daniel and Downs, Alex",
    title = "A Late Triassic Dinosauromorph Assemblage from New Mexico and the Rise of Dinosaurs",
    year = "2007",
    journal = "Science",
    abstract = "It has generally been thought that the first dinosaurs quickly replaced more archaic Late Triassic faunas, either by outcompeting them or when the more archaic faunas suddenly became extinct. Fossils from the Hayden Quarry, in the Upper Triassic Chinle Formation of New Mexico, and an analysis of other regional Upper Triassic assemblages instead imply that the transition was gradual. Some dinosaur relatives preserved in this Chinle assemblage belong to groups previously known only from the Middle and lowermost Upper Triassic outside North America. Thus, the transition may have extended for 15 to 20 million years and was probably diachronous at different paleolatitudes.",
    url = "https://doi.org/10.1126/science.1143325",
    doi = "10.1126/science.1143325",
    openalex = "W2056991518",
    references = "benton1983dinosaur, doi1010160034666791900282, doi1010160169534789901626, doi101016s0031018298001175, doi101017s1477201907002040, doi10108002724634199410011538, doi10108002724634199610011361, doi10108008912960600719988, doi101086413056, doi101098rspb20043047, doi101126science1065522, doi101126science2605109794, doi101146annurevearth251435, doi101671a1097, sereno1997the"
}

The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and Spondylosoma absconditum. The identification of dinosaur apomorphies is jeopardized by the incompleteness of skeletal remains attributed to most basal dinosauromorphs, the skulls and forelimbs of which are particularly poorly known. Nonetheless, Dinosauria can be diagnosed by a suite of derived traits, most of which are related to the anatomy of the pelvic girdle and limb. Some of these are connected to the acquisition of a fully erect bipedal gait, which has been traditionally suggested to represent a key adaptation that allowed, or even promoted, dinosaur radiation during Late Triassic times. Yet, contrary to the classical "competitive" models, dinosaurs did not gradually replace other terrestrial tetrapods over the Late Triassic. In fact, the radiation of the group comprises at least three landmark moments, separated by controversial (Carnian-Norian, Triassic-Jurassic) extinction events. These are mainly characterized by early diversification in Carnian times, a Norian increase in diversity and (especially) abundance, and the occupation of new niches from the Early Jurassic onwards. Dinosaurs arose from fully bipedal ancestors, the diet of which may have been carnivorous or omnivorous. Whereas the oldest dinosaurs were geographically restricted to south Pangea, including rare ornithischians and more abundant basal members of the saurischian lineage, the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as "prosauropods" and coelophysoids.

@article{doi101111j1469185x200900094x,
    author = "Langer, Max C. and Ezcurra, Martín D. and Bittencourt, Jonathas S. and Novas, Fernando E.",
    title = "The origin and early evolution of dinosaurs",
    year = "2009",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = {The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and Spondylosoma absconditum. The identification of dinosaur apomorphies is jeopardized by the incompleteness of skeletal remains attributed to most basal dinosauromorphs, the skulls and forelimbs of which are particularly poorly known. Nonetheless, Dinosauria can be diagnosed by a suite of derived traits, most of which are related to the anatomy of the pelvic girdle and limb. Some of these are connected to the acquisition of a fully erect bipedal gait, which has been traditionally suggested to represent a key adaptation that allowed, or even promoted, dinosaur radiation during Late Triassic times. Yet, contrary to the classical "competitive" models, dinosaurs did not gradually replace other terrestrial tetrapods over the Late Triassic. In fact, the radiation of the group comprises at least three landmark moments, separated by controversial (Carnian-Norian, Triassic-Jurassic) extinction events. These are mainly characterized by early diversification in Carnian times, a Norian increase in diversity and (especially) abundance, and the occupation of new niches from the Early Jurassic onwards. Dinosaurs arose from fully bipedal ancestors, the diet of which may have been carnivorous or omnivorous. Whereas the oldest dinosaurs were geographically restricted to south Pangea, including rare ornithischians and more abundant basal members of the saurischian lineage, the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as "prosauropods" and coelophysoids.},
    url = "https://doi.org/10.1111/j.1469-185x.2009.00094.x",
    doi = "10.1111/j.1469-185x.2009.00094.x",
    openalex = "W2121596487",
    references = "chatterjee2013a, crossref1998encyclopedia, currie2009stratigraphy, doi1010160031018281900924, doi1010160031018295000178, doi101016c20090644421, doi101016jjsames200504002, doi101016jpalaeo200606041, doi101016s0012825203000825, doi101016s0016699580800386, doi101016s0016699583800205, doi101016s0031018298001175, doi101017cbo9780511628948, doi101017s0094837300010575, doi101017s1477201906001970, doi101017s1477201907002040, doi101017s1477201907002246, doi101017s1477201907002271, doi101017s247526300000091x, doi10103820167, doi10106313060577, doi101073pnas0606028103, doi10108002724634199410011538, doi10108002724634199510011271, doi10108002724634199810011115, doi10108002724634199910011124, doi101098rspb20042692, doi101098rspb20080715, doi101098rspl18870117, doi101098rstb19990489, doi101111j109636421985tb01796x, doi101111j10963642200400130x, doi101126science1143325, doi101126science21545391501, doi101126science2645160828, doi101126science2845414616, doi101126science3616622, doi101127njgpa210199841, doi101144gsjgs14720321, doi1012060003009020073021taoeoa20co2, doi101525california97805202420980010001, doi1015468gbdyof, doi1016710272463420020220510toomka20co2, doi1016710272463420072773tclagn20co2, doi101671a1097, doi1023071292217, doi1023071441916, doi1023073889325, doi102475ajss319111253, doi102475ajss32313381, doi104202app20080415, doi10432497802030907329, doi105281zenodo16120887, doi105281zenodo16171435, doi105281zenodo16246150, doi105860choice325663, doi105860choice393984, doi105860choice465038, doi107146moggeosciv32i140904, doi10718895fylantbak30809522, openalexw114509570, openalexw1496509561, openalexw1535663436, openalexw205674743, openalexw2242116350, openalexw2788234611, openalexw2991310333, openalexw3208547338, openalexw3215057009, padian1989presence, rowe1989a, walker1964triassic"
}

Early Dinosaur Discovery Our understanding of the evolution of early dinosaurs is hampered by limited material, especially compared to the many Jurassic and Cretaceous samples. Nesbitt et al. (p. 1530) provide a complete view of a Late Triassic theropod based on several nearly complete skeletons from New Mexico. The dinosaur elucidates the likely relationships between early theropods and shows that some prominent features were already derived by this time. Comparison among Triassic dinosaur fauna and other early species suggests that Triassic North American fauna were diverse but not endemic, perhaps arising from earlier migrants from South America.

@article{nesbitt2009a,
    author = "Nesbitt, Sterling J. and Smith, Nathan D. and Irmis, Randall B. and Turner, Alan H. and Downs, Alex and Norell, Mark A.",
    title = "A Complete Skeleton of a Late Triassic Saurischian and the Early Evolution of Dinosaurs",
    year = "2009",
    journal = "Science",
    abstract = "Early Dinosaur Discovery Our understanding of the evolution of early dinosaurs is hampered by limited material, especially compared to the many Jurassic and Cretaceous samples. Nesbitt et al. (p. 1530) provide a complete view of a Late Triassic theropod based on several nearly complete skeletons from New Mexico. The dinosaur elucidates the likely relationships between early theropods and shows that some prominent features were already derived by this time. Comparison among Triassic dinosaur fauna and other early species suggests that Triassic North American fauna were diverse but not endemic, perhaps arising from earlier migrants from South America.",
    url = "https://doi.org/10.1126/science.1180350",
    doi = "10.1126/science.1180350",
    number = "5959",
    openalex = "W2075629590",
    pages = "1530-1533",
    volume = "326",
    references = "doi101016jsedgeo200605013, doi101017s1477201906001970, doi101017s1477201907002040, doi10108008912960600719988, doi10108010635150701883881, doi101093sysbio461195, doi101098rspb20080715, doi101111j001438202005tb00940x, doi101126science1065522, doi101126science1143325, doi101126science28454232137, doi101126science28554321386, doi1011300091761320020300251tameat20co2, doi1012060003009020073021taoeoa20co2, doi1016710390290218, doi105281zenodo16120887"
}

It was traditionally thought that the oldest known dinosaur assemblages were not diverse, and that their early diversification and numerical dominance over other tetrapods occurred during the latest Triassic. However, new evidence gathered from the lower levels of the Ischigualasto Fm. of Argentina challenges this view. New dinosaur remains are described from this stratigraphical unit, including the new species Chromogisaurus novasi. This taxon is distinguished from other basal dinosauriforms by the presence of proximal caudals without median notch separating the postzygapophyses, femoral lateral surface with deep and large fossa immediately below the trochanteric shelf, and metatarsal II with strongly dorsoventrally asymmetric distal condyles. A phylogenetic analysis found Chromogisaurus to lie at the base of Sauropodomorpha, as a member of Guaibasauridae, an early branch of basal sauropodomorphs composed of Guaibasaurus, Agnosphitys, Panphagia, Saturnalia and Chromogisaurus. Such an affinity is for the first time suggested for Guaibasaurus, whereas Panphagia is not recovered as the most basal sauropodomorph. Furthermore, Chromogisaurus is consistently located as more closely related to Saturnalia than to any other dinosaur. Thus, the Saturnalia + Chromogisaurus clade is named here as the new subfamily Saturnaliinae. In addition, Eoraptor is found to be the sister-taxon of Neotheropoda, and herrerasaurids to be non-eusaurischian saurischians. The new evidence presented here demonstrates that dinosaurs first appeared in the fossil record as a diverse group, although they were a numerically minor component of faunas in which they occur. Accordingly, the early increase of dinosaur diversity and their numerical dominance over other terrestrial tetrapods were diachronous processes, with the latter preceded by a period of low abundance but high diversity.

@article{doi101080147720192010484650,
    author = "Ezcurra, Martín D.",
    title = "A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: a reassessment of dinosaur origin and phylogeny",
    year = "2010",
    journal = "Journal of Systematic Palaeontology",
    abstract = "It was traditionally thought that the oldest known dinosaur assemblages were not diverse, and that their early diversification and numerical dominance over other tetrapods occurred during the latest Triassic. However, new evidence gathered from the lower levels of the Ischigualasto Fm. of Argentina challenges this view. New dinosaur remains are described from this stratigraphical unit, including the new species Chromogisaurus novasi. This taxon is distinguished from other basal dinosauriforms by the presence of proximal caudals without median notch separating the postzygapophyses, femoral lateral surface with deep and large fossa immediately below the trochanteric shelf, and metatarsal II with strongly dorsoventrally asymmetric distal condyles. A phylogenetic analysis found Chromogisaurus to lie at the base of Sauropodomorpha, as a member of Guaibasauridae, an early branch of basal sauropodomorphs composed of Guaibasaurus, Agnosphitys, Panphagia, Saturnalia and Chromogisaurus. Such an affinity is for the first time suggested for Guaibasaurus, whereas Panphagia is not recovered as the most basal sauropodomorph. Furthermore, Chromogisaurus is consistently located as more closely related to Saturnalia than to any other dinosaur. Thus, the Saturnalia + Chromogisaurus clade is named here as the new subfamily Saturnaliinae. In addition, Eoraptor is found to be the sister-taxon of Neotheropoda, and herrerasaurids to be non-eusaurischian saurischians. The new evidence presented here demonstrates that dinosaurs first appeared in the fossil record as a diverse group, although they were a numerically minor component of faunas in which they occur. Accordingly, the early increase of dinosaur diversity and their numerical dominance over other terrestrial tetrapods were diachronous processes, with the latter preceded by a period of low abundance but high diversity.",
    url = "https://doi.org/10.1080/14772019.2010.484650",
    doi = "10.1080/14772019.2010.484650",
    openalex = "W2035329065",
    references = "chatterjee2013a, crossref1998encyclopedia, currie2009stratigraphy, doi101002ara10097, doi101046j10963642200200029x, doi10108002724634199910011124, doi101111j00310239200300301x, doi101111j10960031200800217x, doi101126science10246376, doi101126science28454232137, doi10167102724634200727350asoitp20co2, doi1016710272463420072773tclagn20co2, doi10230730135049, doi105281zenodo16171435, leal2004a, openalexw2242116350, openalexw2560671010, openalexw3215057009, openalexw617951419"
}

@article{doi101016jepsl201107015,
    author = "Irmis, Randall B. and Mundil, Roland and Martz, Jeffrey W. and Parker, William G.",
    title = "High-resolution U–Pb ages from the Upper Triassic Chinle Formation (New Mexico, USA) support a diachronous rise of dinosaurs",
    year = "2011",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/j.epsl.2011.07.015",
    doi = "10.1016/j.epsl.2011.07.015",
    openalex = "W2037559770",
    references = "doi101007bf01134434, doi1010160034666791900282, doi101016jchemgeo200503011, doi101016jepsl200909013, doi101016jgca200511032, doi101016jgca201006017, doi101016s001669959880123x, doi101016s0031018298001175, doi101017cbo9780511536045, doi101017s1755691011020020, doi101017s1755691011020032, doi101098rspb20043047, doi101126science1097023, doi101126science1101012, doi101126science1198467, doi1011300091761320020300251tameat20co2, doi101130g306831, doi101144sp33415, doi101371journalpone0009329, doi1016710390290218, doi103133pp690, doi1056577ffc56302, openalexw1504637003, parker2010the, riggs2003isotopic"
}

The Triassic successions of the Colorado Plateau preserve an important record of vertebrate evolution and climate change, but correlations to a global Triassic framework are hampered by a lack of geochronological control. Tuffaceous sandstones and siltstones were collected from the Upper Triassic Chinle Formation exposed in the Petrified Forest National Park, Arizona, USA, within a refined stratigraphic context of 31 detailed measured sections. U-Pb analyses by the isotope dilution-thermal ionization mass spectrometry (ID-TIMS) method constrain maximum depositional ages for nine tuffaceous beds and provide new insights into the depositional history of the Chinle fluvial system. The base of the Blue Mesa Member of the Chinle Formation is placed at ca. 225 Ma, and the top of the Petrified Forest Member is placed at 208 Ma or younger, bracketing an ̃280-m-thick section that spans nearly the entire Norian Stage of the Late Triassic. Estimated sediment accumulation rates throughout the section reflect extensive hiatuses and/ or sediment removal by channel erosion. The new geochronology for the Chinle Formation underscores the potential pitfalls of correlation of fluvial units based solely on lithostratigraphic criteria. A mid-Norian age (ca. 219-213 Ma) for the distinctive Sonsela conglomeratic sandstone bed constrains the Adamanian-Revueltian land vertebrate faunachron boundary. Our new data permit a significant time overlap between the lower Chinle sequence and the dinosauromorphrich Ischigualasto Formation of northwestern Argentina. Near-contemporaneity of the trans-American deposits and their faunal similarities imply that early dinosaur evolution occurred rapidly across the Americas. © 2011 Geological Society of America.

@article{doi101130b304331,
    author = "Ramezani, Jahandar and Hoke, Gregory D. and Fastovsky, David E. and Bowring, Samuel A. and Therrien, François and Dworkin, S. I. and Atchley, Stacy C. and Nordt, Lee C.",
    title = "High-precision U-Pb zircon geochronology of the Late Triassic Chinle Formation, Petrified Forest National Park (Arizona, USA): Temporal constraints on the early evolution of dinosaurs",
    year = "2011",
    journal = "Geological Society of America Bulletin",
    abstract = "The Triassic successions of the Colorado Plateau preserve an important record of vertebrate evolution and climate change, but correlations to a global Triassic framework are hampered by a lack of geochronological control. Tuffaceous sandstones and siltstones were collected from the Upper Triassic Chinle Formation exposed in the Petrified Forest National Park, Arizona, USA, within a refined stratigraphic context of 31 detailed measured sections. U-Pb analyses by the isotope dilution-thermal ionization mass spectrometry (ID-TIMS) method constrain maximum depositional ages for nine tuffaceous beds and provide new insights into the depositional history of the Chinle fluvial system. The base of the Blue Mesa Member of the Chinle Formation is placed at ca. 225 Ma, and the top of the Petrified Forest Member is placed at 208 Ma or younger, bracketing an ̃280-m-thick section that spans nearly the entire Norian Stage of the Late Triassic. Estimated sediment accumulation rates throughout the section reflect extensive hiatuses and/ or sediment removal by channel erosion. The new geochronology for the Chinle Formation underscores the potential pitfalls of correlation of fluvial units based solely on lithostratigraphic criteria. A mid-Norian age (ca. 219-213 Ma) for the distinctive Sonsela conglomeratic sandstone bed constrains the Adamanian-Revueltian land vertebrate faunachron boundary. Our new data permit a significant time overlap between the lower Chinle sequence and the dinosauromorphrich Ischigualasto Formation of northwestern Argentina. Near-contemporaneity of the trans-American deposits and their faunal similarities imply that early dinosaur evolution occurred rapidly across the Americas. © 2011 Geological Society of America.",
    url = "https://doi.org/10.1130/b30433.1",
    doi = "10.1130/b30433.1",
    openalex = "W2057937776",
    references = "doi1010160034666791900282, doi101016jchemgeo200503011, doi101016jepsl200909013, doi101016s0016703799002045, doi101016s0031018298001175, doi101017cbo9780511536045, doi10102991jb00336, doi101111j1469185x200900094x, doi101126science1101012, doi101126science1154339, doi101126science1198467, doi10113000917613198614567ltpots20co2, doi101130g306831, doi101144sp33415, doi101371journalpone0009329, doi102110jsr2008088, doi1023073514678, doi103133pp521b, doi103133pp644e, doi103133pp690, nesbitt2009a, openalexw1504637003, riggs2003isotopic, therrien2000paleoenvironments"
}

The Ingersoll shale (Santonian) is a small mudstone lens in eastern Alabama, interpreted as an abandoned tidal-channel fill that accumulated rapidly within the lower reaches of a bayhead delta. The diverse biota found in this fossil Lagerstatte includes 14 individual feather specimens, the largest collection known from the Mesozoic of North America. Occurring separately throughout nearly the entire thickness of the clay lens and with a range of sizes and morphologies, the feathers most likely represent a number of theropod species. Based on known taxa in the region, the largest specimen (16.5 cm) may be a rectrix (tail feather) from a dromaeosaurid dinosaur or from a hesperornithid. Smaller feathers may have belonged to a range of shore birds. The best-preserved specimens were found in the finest grained intervals. SEM examination reveals very well preserved microstructure consisting of carbonized rod-shaped bodies ∼1 µm in length, preserved in three dimensions and solid internally. Although identical in size and shape to modern feather-degrading bacilliform bacteria and displaying some bacteria-like features, their alignment along the axis of feather structures indicates that they are more likely the fossil remains of melanosomes, melanin bodies used for color production during life. No three-dimensional arrays or patterned differences of morphotypes have been seen thus far; almost all elements are elongate (apparently eumelanin). Inferred colors for four of the feathers, based on differences in melanosome morphologies, range from gray and brownish gray to black. Whereas the majority of feather-bearing deposits represent inland lakes, the estuarine setting adds a view of coastal feathered theropods preserved in detail by rapid deposition of fine-grained sediment.

@article{doi102110palo2010p10091r,
    author = "Knight, Terrell K. and Bingham, P. Sean and LEWIS, R. D. and Savrda, Charles E.",
    title = "FEATHERS OF THE INGERSOLL SHALE, EUTAW FORMATION (UPPER CRETACEOUS), EASTERN ALABAMA: THE LARGEST COLLECTION OF FEATHERS FROM NORTH AMERICAN MESOZOIC ROCKS",
    year = "2011",
    journal = "Palaios",
    abstract = "The Ingersoll shale (Santonian) is a small mudstone lens in eastern Alabama, interpreted as an abandoned tidal-channel fill that accumulated rapidly within the lower reaches of a bayhead delta. The diverse biota found in this fossil Lagerstatte includes 14 individual feather specimens, the largest collection known from the Mesozoic of North America. Occurring separately throughout nearly the entire thickness of the clay lens and with a range of sizes and morphologies, the feathers most likely represent a number of theropod species. Based on known taxa in the region, the largest specimen (16.5 cm) may be a rectrix (tail feather) from a dromaeosaurid dinosaur or from a hesperornithid. Smaller feathers may have belonged to a range of shore birds. The best-preserved specimens were found in the finest grained intervals. SEM examination reveals very well preserved microstructure consisting of carbonized rod-shaped bodies ∼1 µm in length, preserved in three dimensions and solid internally. Although identical in size and shape to modern feather-degrading bacilliform bacteria and displaying some bacteria-like features, their alignment along the axis of feather structures indicates that they are more likely the fossil remains of melanosomes, melanin bodies used for color production during life. No three-dimensional arrays or patterned differences of morphotypes have been seen thus far; almost all elements are elongate (apparently eumelanin). Inferred colors for four of the feathers, based on differences in melanosome morphologies, range from gray and brownish gray to black. Whereas the majority of feather-bearing deposits represent inland lakes, the estuarine setting adds a view of coastal feathered theropods preserved in detail by rapid deposition of fine-grained sediment.",
    url = "https://doi.org/10.2110/palo.2010.p10-091r",
    doi = "10.2110/palo.2010.p10-091r",
    openalex = "W2071643156",
    references = "schwimmer1993late"
}

ABSTRACT The Post Quarry, within the lower part of the type section of the Upper Triassic Cooper Canyon Formation in southern Garza County, western Texas, contains a remarkably diverse vertebrate assemblage. The Post Quarry has produced: the small temnospondyl Rileymillerus cosgriffi; the metoposaurid Apachesaurus gregorii; possible dicynodonts and eucynodonts; a clevosaurid sphenodontian; non-archosauriform archosauromorphs (Trilophosaurus dornorum, simiosaurians, and possibly Malerisaurus); the phytosaur Leptosuchus; several aetosaurs (Calyptosuchus wellesi, Typothorax coccinarum, Paratypothorax, and Desmatosuchus smalli); the poposauroid Shuvosaurus inexpectatus (“ Chatterjeea elegans ”); the rauisuchid Postosuchus kirkpatricki; an early crocodylomorph; several dinosauromorphs (the lagerpetid Dromomeron gregorii, the silesaurid Technosaurus smalli, a herrerasaurid, and an early neotheropod); and several enigmatic small diapsids. Revised lithostratigraphic correlations of the lower Cooper Canyon Formation with the Tecovas Formation, the occurrence of Leptosuchus, and the overall composition of the assemblage indicate that the Post Quarry falls within the Adamanian biozone, and not the Revueltian biozone. Stratigraphic subdivision of the Adamanian biozone may be possible, and the Post Quarry may be correlative with the upper part of the Adamanian biozone in Arizona. The age of the Post Quarry assemblage is possibly late Lacian or earliest Alaunian (late early Norian or earliest middle Norian), between 220 and 215 Ma.

@article{doi101017s1755691013000376,
    author = "Martz, Jeffrey W. and Mueller, Bill and Nesbitt, Sterling J. and Stocker, Michelle R. and Parker, William G. and Atanassov, Momchil and Fraser, Nicholas C. and Weinbaum, Jonathan C. and Lehane, James R.",
    title = "A taxonomic and biostratigraphic re-evaluation of the Post Quarry vertebrate assemblage from the Cooper Canyon Formation (Dockum Group, Upper Triassic) of southern Garza County, western Texas",
    year = "2012",
    journal = "Earth and Environmental Science Transactions of the Royal Society of Edinburgh",
    abstract = "ABSTRACT The Post Quarry, within the lower part of the type section of the Upper Triassic Cooper Canyon Formation in southern Garza County, western Texas, contains a remarkably diverse vertebrate assemblage. The Post Quarry has produced: the small temnospondyl Rileymillerus cosgriffi; the metoposaurid Apachesaurus gregorii; possible dicynodonts and eucynodonts; a clevosaurid sphenodontian; non-archosauriform archosauromorphs (Trilophosaurus dornorum, simiosaurians, and possibly Malerisaurus); the phytosaur Leptosuchus; several aetosaurs (Calyptosuchus wellesi, Typothorax coccinarum, Paratypothorax, and Desmatosuchus smalli); the poposauroid Shuvosaurus inexpectatus (“ Chatterjeea elegans ”); the rauisuchid Postosuchus kirkpatricki; an early crocodylomorph; several dinosauromorphs (the lagerpetid Dromomeron gregorii, the silesaurid Technosaurus smalli, a herrerasaurid, and an early neotheropod); and several enigmatic small diapsids. Revised lithostratigraphic correlations of the lower Cooper Canyon Formation with the Tecovas Formation, the occurrence of Leptosuchus, and the overall composition of the assemblage indicate that the Post Quarry falls within the Adamanian biozone, and not the Revueltian biozone. Stratigraphic subdivision of the Adamanian biozone may be possible, and the Post Quarry may be correlative with the upper part of the Adamanian biozone in Arizona. The age of the Post Quarry assemblage is possibly late Lacian or earliest Alaunian (late early Norian or earliest middle Norian), between 220 and 215 Ma.",
    url = "https://doi.org/10.1017/s1755691013000376",
    doi = "10.1017/s1755691013000376",
    openalex = "W2105545114",
    references = "doi101016s0031018298001175, doi10108002724634199110011426, doi101098rspl18870117, doi1012063521, doi1023071005355, doi1023072413376, doi102475ajss319111253, doi105281zenodo16171435, doi1056577ffc5285, gregory1972vertebrate, openalexw3215057009, sereno1997the"
}

Prior studies of Mesozoic biodiversity document a diversity peak for dinosaur species in the Campanian stage of the Late Cretaceous, yet have failed to provide explicit causal mechanisms. We provide evidence that a marked increase in North American dinosaur biodiversity can be attributed to dynamic orogenic episodes within the Western Interior Basin (WIB). Detailed fossil occurrences document an association between the shift from Sevier-style, latitudinally arrayed basins to smaller Laramide-style, longitudinally arrayed basins and a well substantiated decreased geographic range/increased taxonomic diversity of megaherbivorous dinosaur species. Dispersal-vicariance analysis demonstrates that the nearly identical biogeographic histories of the megaherbivorous dinosaur clades Ceratopsidae and Hadrosauridae are attributable to rapid diversification events within restricted basins and that isolation events are contemporaneous with known tectonic activity in the region. SymmeTREE analysis indicates that megaherbivorous dinosaur clades exhibited significant variation in diversification rates throughout the Late Cretaceous. Phylogenetic divergence estimates of fossil clades offer a new lower boundary on Laramide surficial deformation that precedes estimates based on sedimentological data alone.

@article{doi101371journalpone0042135,
    author = "Gates, Terry A. and Prieto‐Márquez, Albert and Zanno, Lindsay E.",
    title = "Mountain Building Triggered Late Cretaceous North American Megaherbivore Dinosaur Radiation",
    year = "2012",
    journal = "PLoS ONE",
    abstract = "Prior studies of Mesozoic biodiversity document a diversity peak for dinosaur species in the Campanian stage of the Late Cretaceous, yet have failed to provide explicit causal mechanisms. We provide evidence that a marked increase in North American dinosaur biodiversity can be attributed to dynamic orogenic episodes within the Western Interior Basin (WIB). Detailed fossil occurrences document an association between the shift from Sevier-style, latitudinally arrayed basins to smaller Laramide-style, longitudinally arrayed basins and a well substantiated decreased geographic range/increased taxonomic diversity of megaherbivorous dinosaur species. Dispersal-vicariance analysis demonstrates that the nearly identical biogeographic histories of the megaherbivorous dinosaur clades Ceratopsidae and Hadrosauridae are attributable to rapid diversification events within restricted basins and that isolation events are contemporaneous with known tectonic activity in the region. SymmeTREE analysis indicates that megaherbivorous dinosaur clades exhibited significant variation in diversification rates throughout the Late Cretaceous. Phylogenetic divergence estimates of fossil clades offer a new lower boundary on Laramide surficial deformation that precedes estimates based on sedimentological data alone.",
    url = "https://doi.org/10.1371/journal.pone.0042135",
    doi = "10.1371/journal.pone.0042135",
    openalex = "W2034247742",
    references = "doi101016jpalaeo201206024, doi101016jsedgeo200610001, doi101111j10963642201000642x, doi101139e09050, doi101306m41456c20, doi101371journalpone0024487, doi101371journalpone0032623, doi10167102724634200727373aarolm20co2, lucas1990late"
}

@article{doi101016jcretres201302001,
    author = "Jennings, George R. and Lawton, Timothy F. and Clinkscales, Christopher",
    title = "Late Cretaceous U–Pb tuff ages from the Skunk Ranch Formation and their implications for age of Laramide deformation, Little Hatchet Mountains, southwestern New Mexico, U.S.A.",
    year = "2013",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2013.02.001",
    doi = "10.1016/j.cretres.2013.02.001",
    openalex = "W1989015417",
    references = "lucas1990late"
}

Titanosauriforms represent a diverse and globally distributed clade of neosauropod dinosaurs, but their inter-relationships remain poorly understood. Here we redescribe Lusotitan atalaiensis from the Late Jurassic Lourinhã Formation of Portugal, a taxon previously referred to Brachiosaurus. The lectotype includes cervical, dorsal, and caudal vertebrae, and elements from the forelimb, hindlimb, and pelvic girdle. Lusotitan is a valid taxon and can be diagnosed by six autapomorphies, including the presence of elongate postzygapophyses that project well beyond the posterior margin of the neural arch in anterior-to-middle caudal vertebrae. A new phylogenetic analysis, focused on elucidating the evolutionary relationships of basal titanosauriforms, is presented, comprising 63 taxa scored for 279 characters. Many of these characters are heavily revised or novel to our study, and a number of ingroup taxa have never previously been incorporated into a phylogenetic analysis. We treated quantitative characters as discrete and continuous data in two parallel analyses, and explored the effect of implied weighting. Although we recovered monophyletic brachiosaurid and somphospondylan sister clades within Titanosauriformes, their compositions were affected by alternative treatments of quantitative data and, especially, by the weighting of such data. This suggests that the treatment of quantitative data is important and the wrong decisions might lead to incorrect tree topologies. In particular, the diversity of Titanosauria was greatly increased by the use of implied weights. Our results support the generic separation of the contemporaneous taxa Brachiosaurus, Giraffatitan, and Lusotitan, with the latter recovered as either a brachiosaurid or the sister taxon to Titanosauriformes. Although Janenschia was recovered as a basal macronarian, outside Titanosauria, the sympatric Australodocus provides body fossil evidence for the pre-Cretaceous origin of titanosaurs. We recovered evidence for a sauropod with close affinities to the Chinese taxon Mamenchisaurus in the Late Jurassic Tendaguru beds of Africa, and present new information demonstrating the wider distribution of caudal pneumaticity within Titanosauria. The earliest known titanosauriform body fossils are from the late Oxfordian (Late Jurassic), although trackway evidence indicates a Middle Jurassic origin. Diversity increased throughout the Late Jurassic, and titanosauriforms did not undergo a severe extinction across the Jurassic/Cretaceous boundary, in contrast to diplodocids and non-neosauropods. Titanosauriform diversity increased in the Barremian and Aptian–Albian as a result of radiations of derived somphospondylans and lithostrotians, respectively, but there was a severe drop (up to 40%) in species numbers at, or near, the Albian/Cenomanian boundary, representing a faunal turnover whereby basal titanosauriforms were replaced by derived titanosaurs, although this transition occurred in a spatiotemporally staggered fashion.

@article{doi101111zoj12029,
    author = "Mannion, Philip D. and Upchurch, Paul and Barnes, Rosie N. and Mateus, Octávio",
    title = "Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms",
    year = "2013",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Titanosauriforms represent a diverse and globally distributed clade of neosauropod dinosaurs, but their inter-relationships remain poorly understood. Here we redescribe Lusotitan atalaiensis from the Late Jurassic Lourinhã Formation of Portugal, a taxon previously referred to Brachiosaurus. The lectotype includes cervical, dorsal, and caudal vertebrae, and elements from the forelimb, hindlimb, and pelvic girdle. Lusotitan is a valid taxon and can be diagnosed by six autapomorphies, including the presence of elongate postzygapophyses that project well beyond the posterior margin of the neural arch in anterior-to-middle caudal vertebrae. A new phylogenetic analysis, focused on elucidating the evolutionary relationships of basal titanosauriforms, is presented, comprising 63 taxa scored for 279 characters. Many of these characters are heavily revised or novel to our study, and a number of ingroup taxa have never previously been incorporated into a phylogenetic analysis. We treated quantitative characters as discrete and continuous data in two parallel analyses, and explored the effect of implied weighting. Although we recovered monophyletic brachiosaurid and somphospondylan sister clades within Titanosauriformes, their compositions were affected by alternative treatments of quantitative data and, especially, by the weighting of such data. This suggests that the treatment of quantitative data is important and the wrong decisions might lead to incorrect tree topologies. In particular, the diversity of Titanosauria was greatly increased by the use of implied weights. Our results support the generic separation of the contemporaneous taxa Brachiosaurus, Giraffatitan, and Lusotitan, with the latter recovered as either a brachiosaurid or the sister taxon to Titanosauriformes. Although Janenschia was recovered as a basal macronarian, outside Titanosauria, the sympatric Australodocus provides body fossil evidence for the pre-Cretaceous origin of titanosaurs. We recovered evidence for a sauropod with close affinities to the Chinese taxon Mamenchisaurus in the Late Jurassic Tendaguru beds of Africa, and present new information demonstrating the wider distribution of caudal pneumaticity within Titanosauria. The earliest known titanosauriform body fossils are from the late Oxfordian (Late Jurassic), although trackway evidence indicates a Middle Jurassic origin. Diversity increased throughout the Late Jurassic, and titanosauriforms did not undergo a severe extinction across the Jurassic/Cretaceous boundary, in contrast to diplodocids and non-neosauropods. Titanosauriform diversity increased in the Barremian and Aptian–Albian as a result of radiations of derived somphospondylans and lithostrotians, respectively, but there was a severe drop (up to 40\%) in species numbers at, or near, the Albian/Cenomanian boundary, representing a faunal turnover whereby basal titanosauriforms were replaced by derived titanosaurs, although this transition occurred in a spatiotemporally staggered fashion.",
    url = "https://doi.org/10.1111/zoj.12029",
    doi = "10.1111/zoj.12029",
    openalex = "W1572867283",
    references = "doi101002jez513, doi101016jgr201212009, doi101017s0094837300026543, doi101038nature04633, doi101046j10963642200200029x, doi101073pnas1011369108, doi10108002724634199910011178, doi101080027246342012671204, doi101080147720192011630927, doi101093oso97801985052350010001, doi101111j109600311993tb00209x, doi101111j109600312003tb00376x, doi101111j10960031200800217x, doi101111j109636421998tb00569x, doi101111j1469185x200900107x, doi101111j1469185x201100190x, doi101139e93176, doi101144001676492006032, doi10129879781933789439, doi101371journalpone0001230, doi101371journalpone0006190, doi101371journalpone0006924, doi101371journalpone0017114, doi101525california97805202420980010001, doi101525california97805202420980030015, doi101525california97805202462320010001, doi10167102724634200727931dtftco20co2, doi1023071292217, doi1023073889325, doi102475ajss31695411, doi102475ajss319111253, doi104202app20080049, doi104202app20110051, doi105281zenodo16171435, martinsander2006bone, openalexw1025856234, openalexw2294506137, openalexw2611511275, openalexw3114518543, openalexw603337959, openalexw70084438, ostrom2020stratigraphy"
}

A measured magnetozone sequence defined by 24 sampling sites with normal polarity and 28 sites with reverse polarity characteristic magnetizations was established for the heretofore poorly age-constrained Los Colorados Formation and its dinosaur-bearing vertebrate fauna in the Ischigualasto-Villa Union continental rift basin of Argentina. The polarity pattern in this ∼600-m-thick red-bed section can be correlated to Chrons E7r to E15n of the Newark astrochronological polarity time scale. This represents a time interval from 227 to 213 Ma, indicating that the Los Colorados Formation is predominantly Norian in age, ending more than 11 My before the onset of the Jurassic. The magnetochronology confirms that the underlying Ischigualasto Formation and its vertebrate assemblages including some of the earliest known dinosaurs are of Carnian age. The oldest dated occurrences of vertebrate assemblages with dinosaurs in North America (Chinle Formation) are younger (Norian), and thus the rise of dinosaurs was diachronous across the Americas. Paleogeography of the Ischigualasto and Los Colorados Formations indicates prolonged residence in the austral temperate humid belt where a provincial vertebrate fauna with early dinosaurs may have incubated. Faunal dispersal across the Pangean supercontinent in the development of more cosmopolitan vertebrate assemblages later in the Norian may have been in response to reduced contrasts between climate zones and lowered barriers resulting from decreasing atmospheric pCO2 levels.

@article{doi101073pnas1402369111,
    author = "Kent, Dennis V. and Malnis, Paula Santi and Colombi, Carina E. and Alcober, Oscar A. and Martínez, Ricardo N.",
    title = "Age constraints on the dispersal of dinosaurs in the Late Triassic from magnetochronology of the Los Colorados Formation (Argentina)",
    year = "2014",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "A measured magnetozone sequence defined by 24 sampling sites with normal polarity and 28 sites with reverse polarity characteristic magnetizations was established for the heretofore poorly age-constrained Los Colorados Formation and its dinosaur-bearing vertebrate fauna in the Ischigualasto-Villa Union continental rift basin of Argentina. The polarity pattern in this ∼600-m-thick red-bed section can be correlated to Chrons E7r to E15n of the Newark astrochronological polarity time scale. This represents a time interval from 227 to 213 Ma, indicating that the Los Colorados Formation is predominantly Norian in age, ending more than 11 My before the onset of the Jurassic. The magnetochronology confirms that the underlying Ischigualasto Formation and its vertebrate assemblages including some of the earliest known dinosaurs are of Carnian age. The oldest dated occurrences of vertebrate assemblages with dinosaurs in North America (Chinle Formation) are younger (Norian), and thus the rise of dinosaurs was diachronous across the Americas. Paleogeography of the Ischigualasto and Los Colorados Formations indicates prolonged residence in the austral temperate humid belt where a provincial vertebrate fauna with early dinosaurs may have incubated. Faunal dispersal across the Pangean supercontinent in the development of more cosmopolitan vertebrate assemblages later in the Norian may have been in response to reduced contrasts between climate zones and lowered barriers resulting from decreasing atmospheric pCO2 levels.",
    url = "https://doi.org/10.1073/pnas.1402369111",
    doi = "10.1073/pnas.1402369111",
    openalex = "W2148235107",
    references = "currie2009stratigraphy, doi101016jearscirev201004001, doi101016jgeobios200304008, doi101017cbo9780511564413024, doi101017cbo9780511628948, doi101017s0094837300010575, doi101017s1755691011020020, doi1010292009jb007205, doi101080027246342013818546, doi101111j1365246x1980tb02601x, doi101111j1365246x1990tb05683x, doi101126science1198467, doi101126science1234204, doi101130g22967a1, doi101130g306831, doi101175jcli39901, doi101371journalpone0009329, parker2010the"
}

Abstract Laser ablation‐multi collector‐inductively coupled mass spectrometry U ‐ P b geochronology, detailed field mapping and stratigraphic data offer improved insights into the timing and style of Laramide deformation and basin development in the Little Hatchet Mountains, southwestern New Mexico, USA, a key locality in the ‘southern Laramide province.’ The Laramide synorogenic section in the northern Little Hatchet Mountains comprises upper Campanian to Maastrichtian strata consisting of the Ringbone and Skunk Ranch formations, with a preserved maximum thickness of >2400 m, and the correlative Hidalgo Formation with a total thickness >1700 m. The Ringbone Formation and superjacent Skunk Ranch Formation are each generally composed of (1) a basal conglomerate member; (2) a middle member consisting of lacustrine shale, limestone, sandstone, and interbedded ash‐fall tuffs; and (3) an upper sandstone and conglomerate member. Basaltic andesite flows are intercalated with the upper member of the Ringbone Formation and the middle member of the Skunk Ranch Formation. The Hidalgo Formation, which crops out in the northern part of the range, is dominantly composed of basaltic andesite breccias and flows equivalent to those of the Ringbone and Skunk Ranch formations. The Laramide section was deposited in an intermontane basin partitioned across intrabasinal thrust structures, which controlled growth‐stratal development. U ‐ P b zircon ages from five tuffs indicate that the age range of the Laramide sedimentary succession is ca. 75–70 Ma. U‐ P b detrital‐zircon age data (n = 356 analyses) from the Ringbone Formation and a Lower Cretaceous unit indicate sediment contribution from uplifted Lower and Upper Cretaceous rocks adjacent to the basin and the contemporary Tarahumara magmatic arc in nearby northern Sonora, Mexico. The new ages, combined with published data, indicate that uplift, basin development, and magmatism in the region proceeded diachronously northeastwards as the subducting Farallon slab flattened under northern Mexico and southern New Mexico from Campanian to Palaeogene time.

@article{doi101111bre12083,
    author = "Clinkscales, Christopher and Lawton, Timothy F.",
    title = "Timing of Late Cretaceous shortening and basin development, Little Hatchet Mountains, southwestern New Mexico, USA – implications for regional Laramide tectonics",
    year = "2014",
    journal = "Basin Research",
    abstract = "Abstract Laser ablation‐multi collector‐inductively coupled mass spectrometry U ‐ P b geochronology, detailed field mapping and stratigraphic data offer improved insights into the timing and style of Laramide deformation and basin development in the Little Hatchet Mountains, southwestern New Mexico, USA, a key locality in the ‘southern Laramide province.’ The Laramide synorogenic section in the northern Little Hatchet Mountains comprises upper Campanian to Maastrichtian strata consisting of the Ringbone and Skunk Ranch formations, with a preserved maximum thickness of >2400 m, and the correlative Hidalgo Formation with a total thickness >1700 m. The Ringbone Formation and superjacent Skunk Ranch Formation are each generally composed of (1) a basal conglomerate member; (2) a middle member consisting of lacustrine shale, limestone, sandstone, and interbedded ash‐fall tuffs; and (3) an upper sandstone and conglomerate member. Basaltic andesite flows are intercalated with the upper member of the Ringbone Formation and the middle member of the Skunk Ranch Formation. The Hidalgo Formation, which crops out in the northern part of the range, is dominantly composed of basaltic andesite breccias and flows equivalent to those of the Ringbone and Skunk Ranch formations. The Laramide section was deposited in an intermontane basin partitioned across intrabasinal thrust structures, which controlled growth‐stratal development. U ‐ P b zircon ages from five tuffs indicate that the age range of the Laramide sedimentary succession is ca. 75–70 Ma. U‐ P b detrital‐zircon age data (n = 356 analyses) from the Ringbone Formation and a Lower Cretaceous unit indicate sediment contribution from uplifted Lower and Upper Cretaceous rocks adjacent to the basin and the contemporary Tarahumara magmatic arc in nearby northern Sonora, Mexico. The new ages, combined with published data, indicate that uplift, basin development, and magmatism in the region proceeded diachronously northeastwards as the subducting Farallon slab flattened under northern Mexico and southern New Mexico from Campanian to Palaeogene time.",
    url = "https://doi.org/10.1111/bre.12083",
    doi = "10.1111/bre.12083",
    openalex = "W2098996266",
    references = "lucas1990late"
}

Abstract High-precision geochronology provides unprecedented insights into the depositional history of the Upper Triassic Chinle Formation of the Colorado Plateau, as well as its paleoenvironmental and paleobiological records. The Chinle succession exposed in the Petrified Forest National Park (PEFO) and vicinity, Arizona, includes two large-scale alluvial composite sequences. Although each composite sequence fines upward, the upper composite sequence is more dominated by coarser-grained deposits. Petrographic analysis of sandstone lithic content indicates an upward decrease in the proportion of volcanic rock fragments in each composite sequence. Paleocurrent indicators in the lower composite sequence suggest a variable paleoflow direction, whereas northward paleoflow dominated the upper composite sequence. The change in paleoflow appears to coincide with a reorganization of alluvial depositional processes and associated source terranes, and precedes a rapid acceleration in basin subsidence. Climate proxy records from paleosol geochemistry indicate a gradual shift from humid to dry conditions across the transition between the lower and upper composite sequences and the Adamanian–Revueltian biotic turnover. Composite-sequence depositional reorganization, climatic shift and biologic turnover, in turn, appear to coincide with episodes of magmatism recorded in Triassic granitoid plutons presently exposed in southern California. Taken collectively, these observations suggest that the Late Triassic depositional, climatic, and ecologic history at PEFO may be related to emergence of the incipient Cordilleran magmatic arc along the convergent western margin of Pangea. A new U-Pb date for the lower part of the Chinle Formation suggests that most or all of the formation was deposited in the Norian Stage.

@article{doi102110jsr201389,
    author = "Atchley, S. C. and Nordt, Lee C. and Dworkin, S. I. and Ramezani, Jahandar and Parker, William G. and Ash, Sidney R. and Bowring, Samuel A.",
    title = "A Linkage Among Pangean Tectonism, Cyclic Alluviation, Climate Change, and Biologic Turnover In the Late Triassic: The Record From The Chinle Formation, Southwestern United States",
    year = "2014",
    journal = "Journal of Sedimentary Research",
    abstract = "Abstract High-precision geochronology provides unprecedented insights into the depositional history of the Upper Triassic Chinle Formation of the Colorado Plateau, as well as its paleoenvironmental and paleobiological records. The Chinle succession exposed in the Petrified Forest National Park (PEFO) and vicinity, Arizona, includes two large-scale alluvial composite sequences. Although each composite sequence fines upward, the upper composite sequence is more dominated by coarser-grained deposits. Petrographic analysis of sandstone lithic content indicates an upward decrease in the proportion of volcanic rock fragments in each composite sequence. Paleocurrent indicators in the lower composite sequence suggest a variable paleoflow direction, whereas northward paleoflow dominated the upper composite sequence. The change in paleoflow appears to coincide with a reorganization of alluvial depositional processes and associated source terranes, and precedes a rapid acceleration in basin subsidence. Climate proxy records from paleosol geochemistry indicate a gradual shift from humid to dry conditions across the transition between the lower and upper composite sequences and the Adamanian–Revueltian biotic turnover. Composite-sequence depositional reorganization, climatic shift and biologic turnover, in turn, appear to coincide with episodes of magmatism recorded in Triassic granitoid plutons presently exposed in southern California. Taken collectively, these observations suggest that the Late Triassic depositional, climatic, and ecologic history at PEFO may be related to emergence of the incipient Cordilleran magmatic arc along the convergent western margin of Pangea. A new U-Pb date for the lower part of the Chinle Formation suggests that most or all of the formation was deposited in the Norian Stage.",
    url = "https://doi.org/10.2110/jsr.2013.89",
    doi = "10.2110/jsr.2013.89",
    openalex = "W2122960116",
    references = "doi1010160016703792901426, doi101016jchemgeo200503011, doi101016jrevpalbo201211001, doi101016s0016706100000975, doi101017s1755691011020020, doi101017s1755691013000376, doi1010292010gc003478, doi1010292010gc003479, doi101086342865, doi101086648217, doi101103physrevc41889, doi101371journalpone0009329, doi1016660094837320000260137ccpfrt20co2, doi105860choice444462, parker2010the, therrien2000paleoenvironments"
}

We report on tanystropheids from the Late Triassic (middle Norian) Hayden Quarry of northern New Mexico (Chinle Formation, Hayden Quarry). These elements, consisting of isolated vertebrae and appendicular bones, represent the first unambiguously identified tanystropheid from western North America and likely the latest occurrence of the group, postdating Tanytrachelos in the eastern United States. A new phylogenetic analysis of early saurians identifies synapomorphies of tanystropheid subclades, which are recognized in the recovered vertebrae and a calcaneum. The femora are consistent with referral to Tanystropheidae. There is no clear association of the remains, however, so we refrain from erecting a new taxon. The analysis also indicates that the Hayden Quarry tanystropheid fossils belong to a newly recognized clade including the Late Triassic taxa Langobardisaurus and Tanytrachelos. Because most tanystropheid specimens are two-dimensionally crushed skeletons, the Hayden Quarry tanystropheid fossils provide valuable insights into the three-dimensional osteology of derived tanystropheids. The most striking feature of the Hayden vertebrae is a rugose, flattened expansion of the neural spines in the dorsal, sacral, and caudal regions, probably linked to a ligamentous bracing system. These fossils and others from Late Triassic sites in the American West suggest that tanystropheids underwent a previously unrecognized radiation in North America just prior to their extinction.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

@article{doi101080027246342014911186,
    author = "Pritchard, Adam C. and Turner, Alan H. and Nesbitt, Sterling J. and Irmis, Randall B. and Smith, Nathan D.",
    title = "Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae",
    year = "2015",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "We report on tanystropheids from the Late Triassic (middle Norian) Hayden Quarry of northern New Mexico (Chinle Formation, Hayden Quarry). These elements, consisting of isolated vertebrae and appendicular bones, represent the first unambiguously identified tanystropheid from western North America and likely the latest occurrence of the group, postdating Tanytrachelos in the eastern United States. A new phylogenetic analysis of early saurians identifies synapomorphies of tanystropheid subclades, which are recognized in the recovered vertebrae and a calcaneum. The femora are consistent with referral to Tanystropheidae. There is no clear association of the remains, however, so we refrain from erecting a new taxon. The analysis also indicates that the Hayden Quarry tanystropheid fossils belong to a newly recognized clade including the Late Triassic taxa Langobardisaurus and Tanytrachelos. Because most tanystropheid specimens are two-dimensionally crushed skeletons, the Hayden Quarry tanystropheid fossils provide valuable insights into the three-dimensional osteology of derived tanystropheids. The most striking feature of the Hayden vertebrae is a rugose, flattened expansion of the neural spines in the dorsal, sacral, and caudal regions, probably linked to a ligamentous bracing system. These fossils and others from Late Triassic sites in the American West suggest that tanystropheids underwent a previously unrecognized radiation in North America just prior to their extinction.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP",
    url = "https://doi.org/10.1080/02724634.2014.911186",
    doi = "10.1080/02724634.2014.911186",
    openalex = "W2141363548",
    references = "doi101017s1755691013000376"
}

Abstract The Lobo Formation of southwestern New Mexico consists of spatially variable continental successions attributed to the Laramide orogeny (80–40 Myr), although its age and provenance are virtually undocumented. This study combines sedimentological, magnetostratigraphical and geochronological data to infer the timing and origin of the Lobo Formation. Measured sections of Lobo strata at two locations, Capitol Dome in the Florida Mountains and in the Victorio Mountains, indicate significant differences in depositional environments and sediment provenance. At Capitol Dome, where Lobo strata were deposited above a syncline developed in Palaeozoic strata, deposition took place in fluvial, palustrine and marginal lacustrine settings, with alluvial‐fan deposits only at the top of the formation. Combined magnetostratigraphy and a young U–Pb detrital zircon age suggest deposition of the section at Capitol Dome from ~60 to 52 Ma. The Lobo Formation in the Victorio Mountains was deposited in alluvial‐fan and fluvial settings; the age of deposition is poorly bracketed between 66 ± 2 Ma, the weighted‐mean age of two young zircons, and middle Eocene (~40 Ma), the approximate age of overlying volcanic rocks. U–Pb zircon ages from sandstones at the Victorio and Capitol Dome localities indicate that different source rocks provided sediment to the Lobo Formation. Local Proterozoic basement (~1.47–1.45 Ga) dominated the source of the Lobo Formation in the Victorio Mountains, consistent with abundant granitic clasts that are present in the proximal facies there; a diverse range of grain ages suggest that recycled Lower Cretaceous strata provided the dominant source for Lobo Formation sediment at the Capitol Dome locality. The U–Pb data suggest that the depositional systems at the two sites were not connected. Contrasts in depositional setting and detrital zircon provenance indicate that the Palaeogene Lobo Formation in southwest New Mexico was deposited in an assemblage of local depositional settings, possibly in separate structural basins, as a consequence of Laramide tectonics in the region.

@article{doi101111bre12226,
    author = "los Santos, Marie G. De and Lawton, Timothy F. and Copeland, Peter and Licht, Alexis and Hall, Stuart A.",
    title = "Magnetostratigraphy, age and depositional environment of the Lobo Formation, southwest New Mexico: implications for the Laramide orogeny in the southern Rocky Mountains",
    year = "2016",
    journal = "Basin Research",
    abstract = "Abstract The Lobo Formation of southwestern New Mexico consists of spatially variable continental successions attributed to the Laramide orogeny (80–40 Myr), although its age and provenance are virtually undocumented. This study combines sedimentological, magnetostratigraphical and geochronological data to infer the timing and origin of the Lobo Formation. Measured sections of Lobo strata at two locations, Capitol Dome in the Florida Mountains and in the Victorio Mountains, indicate significant differences in depositional environments and sediment provenance. At Capitol Dome, where Lobo strata were deposited above a syncline developed in Palaeozoic strata, deposition took place in fluvial, palustrine and marginal lacustrine settings, with alluvial‐fan deposits only at the top of the formation. Combined magnetostratigraphy and a young U–Pb detrital zircon age suggest deposition of the section at Capitol Dome from \textasciitilde 60 to 52 Ma. The Lobo Formation in the Victorio Mountains was deposited in alluvial‐fan and fluvial settings; the age of deposition is poorly bracketed between 66 ± 2 Ma, the weighted‐mean age of two young zircons, and middle Eocene (\textasciitilde 40 Ma), the approximate age of overlying volcanic rocks. U–Pb zircon ages from sandstones at the Victorio and Capitol Dome localities indicate that different source rocks provided sediment to the Lobo Formation. Local Proterozoic basement (\textasciitilde 1.47–1.45 Ga) dominated the source of the Lobo Formation in the Victorio Mountains, consistent with abundant granitic clasts that are present in the proximal facies there; a diverse range of grain ages suggest that recycled Lower Cretaceous strata provided the dominant source for Lobo Formation sediment at the Capitol Dome locality. The U–Pb data suggest that the depositional systems at the two sites were not connected. Contrasts in depositional setting and detrital zircon provenance indicate that the Palaeogene Lobo Formation in southwest New Mexico was deposited in an assemblage of local depositional settings, possibly in separate structural basins, as a consequence of Laramide tectonics in the region.",
    url = "https://doi.org/10.1111/bre.12226",
    doi = "10.1111/bre.12226",
    openalex = "W2556729877",
    references = "lucas1990late"
}

Three small and gracile jaw fragments are recovered from the Boren Quarry, one of the lowest fossil quarries of the Upper Triassic Dockum Group of Texas. The specimens are referred to archosauromorphs, where the morphology of the dentary and teeth of two specimens resemble what is observed in basal saurischians. Growing numbers of early dinosaur fossils from the lowest quarries of the Dockum Group of Texas which correspond to the lowermost Norian raises doubts concerning early dinosaur dispersal during the late Carnian-early Norian interval and the first occurrence of North American dinosaurs which might have happened earlier than previously suggested.

@article{doi1010800891296320171333609,
    author = "Sarıgül, Volkan",
    title = "New archosauromorph fragments from the Dockum Group of Texas and assessment of the earliest dinosaurs in North America",
    year = "2017",
    journal = "Historical Biology",
    abstract = "Three small and gracile jaw fragments are recovered from the Boren Quarry, one of the lowest fossil quarries of the Upper Triassic Dockum Group of Texas. The specimens are referred to archosauromorphs, where the morphology of the dentary and teeth of two specimens resemble what is observed in basal saurischians. Growing numbers of early dinosaur fossils from the lowest quarries of the Dockum Group of Texas which correspond to the lowermost Norian raises doubts concerning early dinosaur dispersal during the late Carnian-early Norian interval and the first occurrence of North American dinosaurs which might have happened earlier than previously suggested.",
    url = "https://doi.org/10.1080/08912963.2017.1333609",
    doi = "10.1080/08912963.2017.1333609",
    openalex = "W2624364871",
    references = "doi101016jepsl200909013, doi101016s0031018298001175, doi10108002724634199810011115, doi101098rspl18870117, doi1012063521, doi1018814epiiugs2013v36i3002, doi1023071005355, doi105281zenodo16171435, doi10718895fylantbak30806570, gregory1972vertebrate, openalexw2912219260, openalexw3215057009"
}

The Late Triassic (Norian-early Rhaetian) Fleming Fjord Formation of central East Greenland preserves a diverse fossil fauna, including both body and trace fossils. Trackways of large quadrupedal archosaurs, although already reported in 1994 and mentioned in subsequent publications, are here described and figured in detail for the first time, based on photogrammetric data collected during fieldwork in 2012. Two trackways can be referred to Eosauropus, while a third, bipedal trackway may be referred to Evazoum, both of which have been considered to represent sauropodomorph dinosaur tracks. Both the Evazoum and the Eosauropus trackways are distinctly larger than other trackways referred to the respective ichnogenera. The trackmaker of the best preserved Eosauropus trackway is constrained using a synapomorphy-based approach. The quadrupedal posture, the entaxonic pes structure, and five weight-bearing digits indicate a derived sauropodiform trackmaker. Other features exhibited by the tracks, including the semi-digitigrade pes and the laterally deflected unguals, are commonly considered synapomorphies of more exclusive clades within Sauropoda. The present trackway documents an early acquisition of a eusauropod-like pes anatomy while retaining a well-developed claw on pedal digit IV, which is reduced in eusauropods. Although unequivocal evidence for sauropod dinosaurs is no older than the Early Jurassic, the present trackway provides evidence for a possible Triassic origin of the group.

@article{doi104202app003742017,
    author = "Lallensack, Jens N. and Klein, Hendrik and Milàn, Jesper and Wings, Oliver and Mateus, Octávio and Clemmensen, Lars B.",
    title = "Sauropodomorph dinosaur trackways from the Fleming Fjord Formation of East Greenland: evidence for Late Triassic sauropods",
    year = "2017",
    journal = "Acta Palaeontologica Polonica",
    abstract = "The Late Triassic (Norian-early Rhaetian) Fleming Fjord Formation of central East Greenland preserves a diverse fossil fauna, including both body and trace fossils. Trackways of large quadrupedal archosaurs, although already reported in 1994 and mentioned in subsequent publications, are here described and figured in detail for the first time, based on photogrammetric data collected during fieldwork in 2012. Two trackways can be referred to Eosauropus, while a third, bipedal trackway may be referred to Evazoum, both of which have been considered to represent sauropodomorph dinosaur tracks. Both the Evazoum and the Eosauropus trackways are distinctly larger than other trackways referred to the respective ichnogenera. The trackmaker of the best preserved Eosauropus trackway is constrained using a synapomorphy-based approach. The quadrupedal posture, the entaxonic pes structure, and five weight-bearing digits indicate a derived sauropodiform trackmaker. Other features exhibited by the tracks, including the semi-digitigrade pes and the laterally deflected unguals, are commonly considered synapomorphies of more exclusive clades within Sauropoda. The present trackway documents an early acquisition of a eusauropod-like pes anatomy while retaining a well-developed claw on pedal digit IV, which is reduced in eusauropods. Although unequivocal evidence for sauropod dinosaurs is no older than the Early Jurassic, the present trackway provides evidence for a possible Triassic origin of the group.",
    url = "https://doi.org/10.4202/app.00374.2017",
    doi = "10.4202/app.00374.2017",
    openalex = "W2750743522",
    references = "doi1034194bullgguv1396681"
}

Ceratopsids ("horned dinosaurs") are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

@article{doi107717peerj3342,
    author = "Farke, Andrew A. and Phillips, George E.",
    title = "The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA)",
    year = "2017",
    journal = "PeerJ",
    abstract = {Ceratopsids ("horned dinosaurs") are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.},
    url = "https://doi.org/10.7717/peerj.3342",
    doi = "10.7717/peerj.3342",
    openalex = "W2580404050",
    references = "longrich2016a, schwimmer1993late"
}

Abstract A new sauropodomorph dinosaur from the Late Triassic Candelária Sequence (Santa Maria Formation), south Brazil, Bagualosaurus agudoensis gen. et sp. nov., helps to fill a morphological gap between the previously known Carnian members of the group and younger sauropodomorphs. In some aspects, the skull, lower jaw, and dental anatomy of the new taxon approaches that seen in Norian forms like Pantydraco caducus, Efraasia minor, and Plateosaurus engelhardti. On the contrary, the post-cranial skeleton is broadly reminiscent of coeval, early dinosaurs. Although not reaching the size of most Norian and younger sauropodomorphs, B. agudoensis is significantly larger than coeval forms. The new data thus suggest that modifications in skull anatomy, possibly related to more efficient herbivorous habits, appeared early in sauropodomorph evolution, along with a moderate increase in size, followed in post-Carnian times by further increase in size, accompanied by more radical changes in post-cranial anatomy.

@article{doi101093zoolinneanzly028,
    author = "Pretto, Flávio Augusto and Langer, Max C. and Schultz, César Leandro",
    title = "A new dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Brazil provides insights on the evolution of sauropodomorph body plan",
    year = "2018",
    journal = "Zoological Journal of the Linnean Society",
    abstract = "Abstract A new sauropodomorph dinosaur from the Late Triassic Candelária Sequence (Santa Maria Formation), south Brazil, Bagualosaurus agudoensis gen. et sp. nov., helps to fill a morphological gap between the previously known Carnian members of the group and younger sauropodomorphs. In some aspects, the skull, lower jaw, and dental anatomy of the new taxon approaches that seen in Norian forms like Pantydraco caducus, Efraasia minor, and Plateosaurus engelhardti. On the contrary, the post-cranial skeleton is broadly reminiscent of coeval, early dinosaurs. Although not reaching the size of most Norian and younger sauropodomorphs, B. agudoensis is significantly larger than coeval forms. The new data thus suggest that modifications in skull anatomy, possibly related to more efficient herbivorous habits, appeared early in sauropodomorph evolution, along with a moderate increase in size, followed in post-Carnian times by further increase in size, accompanied by more radical changes in post-cranial anatomy.",
    url = "https://doi.org/10.1093/zoolinnean/zly028",
    doi = "10.1093/zoolinnean/zly028",
    openalex = "W2804989805",
    references = "doi101007bf02985709, doi101016jcub201609040, doi101016jgr201801005, doi101080031155182015994114"
}

The Cenomanian to Maastrichtian of the Late Cretaceous saw the flooding of the interior of North America by the Western Interior Seaway, which created the eastern landmass of Appalachia and the western landmass of Laramidia. Though Appalachian dinosaur faunas are poorly known, they are nevertheless important for understanding Cretaceous dinosaur paleobiogeography and ecology. In order to better track the vicariance of eastern and western North American dinosaur faunas over the duration of the Cretaceous, the former were compared with the latter from the Aptian to Maastrichtian Stages of the Late Cretaceous using several similarity indices. The data gathered from biogeographic similarity indices suggest that an almost completely homogenous North American dinosaur fauna found in the Early Cretaceous experienced significant vicariance, splitting into a Laramidian fauna differentiated by the presence of ceratopsids, pachycephalosaurids, saurolophids, lambeosaurines, ankylosaurids, therizinosaurids, and troodontids and an Appalachian fauna characterized by the lack of the aforementioned groups and the presence of non-hadrosaurid hadrosauroids, massive hadrosauroids, basal hadrosaurids, leptoceratopsians, "intermediate"-grade tyrannosauroids, and nodosaurids between the Cenomanian and Campanian, with these two faunas later experiencing limited dispersal after the disappearance of the Western Interior Seaway from the American Interior during the Maastrichtian. Dinosaur provincialism and ecology on Appalachia are also investigated and discussed. Though the fossil record of dinosaurs for parts of the Cretaceous is poor throughout North America and in the eastern portion of the continent especially, the analyses herein nevertheless allow for a greater glimpse at dinosaur biogeography and ecology in Appalachia and in North America generally during the time.

@article{doi1026879801,
    author = "Brownstein, Chase Doran",
    title = "The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia",
    year = "2018",
    journal = "Palaeontologia Electronica",
    abstract = {The Cenomanian to Maastrichtian of the Late Cretaceous saw the flooding of the interior of North America by the Western Interior Seaway, which created the eastern landmass of Appalachia and the western landmass of Laramidia. Though Appalachian dinosaur faunas are poorly known, they are nevertheless important for understanding Cretaceous dinosaur paleobiogeography and ecology. In order to better track the vicariance of eastern and western North American dinosaur faunas over the duration of the Cretaceous, the former were compared with the latter from the Aptian to Maastrichtian Stages of the Late Cretaceous using several similarity indices. The data gathered from biogeographic similarity indices suggest that an almost completely homogenous North American dinosaur fauna found in the Early Cretaceous experienced significant vicariance, splitting into a Laramidian fauna differentiated by the presence of ceratopsids, pachycephalosaurids, saurolophids, lambeosaurines, ankylosaurids, therizinosaurids, and troodontids and an Appalachian fauna characterized by the lack of the aforementioned groups and the presence of non-hadrosaurid hadrosauroids, massive hadrosauroids, basal hadrosaurids, leptoceratopsians, "intermediate"-grade tyrannosauroids, and nodosaurids between the Cenomanian and Campanian, with these two faunas later experiencing limited dispersal after the disappearance of the Western Interior Seaway from the American Interior during the Maastrichtian. Dinosaur provincialism and ecology on Appalachia are also investigated and discussed. Though the fossil record of dinosaurs for parts of the Cretaceous is poor throughout North America and in the eastern portion of the continent especially, the analyses herein nevertheless allow for a greater glimpse at dinosaur biogeography and ecology in Appalachia and in North America generally during the time.},
    url = "https://doi.org/10.26879/801",
    doi = "10.26879/801",
    openalex = "W2788818218",
    references = "longrich2016a, schwimmer1993late"
}

The Upper Triassic Dockum Group of Garza County, Texas (lower, middle, and upper Cooper Canyon Formation) captures the radiation of Triassic non-marine tetrapods by preserving a variety of Late Triassic taxa from the southwestern United States. Our understanding of the vertebrate assemblage from these strata largely comes from a single site, the Post Quarry (lower Cooper Canyon Formation), with previous research documenting a variety of temnospondyls, sphenodontians, non-archosauriform archosauromorphs, and archosauriforms including a phytosaur, three species of aetosaurs, a poposauroid, a rauisuchid, a crocodylomorph, and several dinosauromorphs. To more completely reconstruct the vertebrate assemblage of the Dockum Group of Garza County we use an apomorphy-based approach to identify morphologically similar disarticulated and fragmentary elements from a variety of localities that span the entire Cooper Canyon Formation (Norian-Rhaetian), allowing assignments from the large clade level to the species level. Many skeletal elements are incomplete yet diagnostic and are assigned to the least inclusive clade if discrete character states do not allow for an unambiguous species-level identification. We identify new specimens referable to numerous clades including Tanystropheidae, Allokotosauria + Prolacerta + Archosauriformes, Vancleavea + Litorosuchus, Phytosauria, Paracrocodylomorpha, Dinosauriformes, and Saurischia, in addition to additional species identifications of the aetosaur Scutarx deltatlyus, and the dinosauromorph Dromomeron gregorii. Our study of this material demonstrates the utility of an apomorphy-based approach in making testable and repeatable observations for identifying small, isolated fragmentary fossil tetrapod material to reconstruct a more accurate faunal hypothesis for a portion of the Late Triassic of Texas. Previous claims of the earliest dinosaurs from near the base of the Dockum Group do not pass the apomorphy-based identification test, and the question of whether the oldest known North American dinosaurs are present in the Chinle Formation or Dockum Group can be resolved by utilizing vertebrate biostratigraphic correlation. Our revision of these fossil assemblages supports the hypothesis that early diapsids, early archosauromorphs, and non-dinosaurian dinosauromorphs were more common, diverse, and widespread in low latitudes during this time than previously thought.

@article{doi105070p9351039960,
    author = "Lessner, Emily J. and Parker, William G. and Marsh, Adam D. and Nesbitt, Sterling J. and Irmis, Randall B. and Mueller, Bill",
    title = "New insights into Late Triassic dinosauromorph-bearing assemblages from Texas using apomorphy-based identifications",
    year = "2018",
    journal = "PaleoBios",
    abstract = "The Upper Triassic Dockum Group of Garza County, Texas (lower, middle, and upper Cooper Canyon Formation) captures the radiation of Triassic non-marine tetrapods by preserving a variety of Late Triassic taxa from the southwestern United States. Our understanding of the vertebrate assemblage from these strata largely comes from a single site, the Post Quarry (lower Cooper Canyon Formation), with previous research documenting a variety of temnospondyls, sphenodontians, non-archosauriform archosauromorphs, and archosauriforms including a phytosaur, three species of aetosaurs, a poposauroid, a rauisuchid, a crocodylomorph, and several dinosauromorphs. To more completely reconstruct the vertebrate assemblage of the Dockum Group of Garza County we use an apomorphy-based approach to identify morphologically similar disarticulated and fragmentary elements from a variety of localities that span the entire Cooper Canyon Formation (Norian-Rhaetian), allowing assignments from the large clade level to the species level. Many skeletal elements are incomplete yet diagnostic and are assigned to the least inclusive clade if discrete character states do not allow for an unambiguous species-level identification. We identify new specimens referable to numerous clades including Tanystropheidae, Allokotosauria + Prolacerta + Archosauriformes, Vancleavea + Litorosuchus, Phytosauria, Paracrocodylomorpha, Dinosauriformes, and Saurischia, in addition to additional species identifications of the aetosaur Scutarx deltatlyus, and the dinosauromorph Dromomeron gregorii. Our study of this material demonstrates the utility of an apomorphy-based approach in making testable and repeatable observations for identifying small, isolated fragmentary fossil tetrapod material to reconstruct a more accurate faunal hypothesis for a portion of the Late Triassic of Texas. Previous claims of the earliest dinosaurs from near the base of the Dockum Group do not pass the apomorphy-based identification test, and the question of whether the oldest known North American dinosaurs are present in the Chinle Formation or Dockum Group can be resolved by utilizing vertebrate biostratigraphic correlation. Our revision of these fossil assemblages supports the hypothesis that early diapsids, early archosauromorphs, and non-dinosaurian dinosauromorphs were more common, diverse, and widespread in low latitudes during this time than previously thought.",
    url = "https://doi.org/10.5070/p9351039960",
    doi = "10.5070/p9351039960",
    openalex = "W2884213488",
    references = "doi1010800891296320171333609, doi107717peerj1583"
}

The giant tyrannosaurids were the apex predators of western North America and Asia during the close of the Cretaceous Period. Although many tyrannosaurid species are known from numerous skeletons representing multiple growth stages, the early evolution of Tyrannosauridae remains poorly known, with the well-known species temporally restricted to the middle Campanian-latest Maastrichtian (∼77-66 Ma). The recent discovery of a new tyrannosaurid, Lythronax argestes, from the Wahweap Formation of Utah provided new data on early Campanian (∼80 Ma) tyrannosaurids. Nevertheless, the early evolution of Tyrannosauridae is still largely unsampled. We report a new tyrannosaurid represented by an associated skeleton from the lower Campanian Allison Member of the Menefee Formation of New Mexico. Despite fragmentation of much of the axial and appendicular skeleton prior to discovery, the frontals, a metacarpal, and two pedal phalanges are well-preserved. The frontals exhibit an unambiguous autapomorphy and a second potential autapomorphy that distinguish this specimen from all other tyrannosaurids. Therefore, the specimen is made the holotype of the new genus and species Dynamoterror dynastes. A phylogenetic analysis places Dynamoterror dynastes in the tyrannosaurid subclade Tyrannosaurinae. Laser-scanning the frontals and creation of a composite 3-D digital model allows the frontal region of the skull roof of Dynamoterror to be reconstructed.

@article{doi107717peerj5749,
    author = "McDonald, Andrew T. and Wolfe, Douglas G. and Dooley, Alton C.",
    title = "A new tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico",
    year = "2018",
    journal = "PeerJ",
    abstract = "The giant tyrannosaurids were the apex predators of western North America and Asia during the close of the Cretaceous Period. Although many tyrannosaurid species are known from numerous skeletons representing multiple growth stages, the early evolution of Tyrannosauridae remains poorly known, with the well-known species temporally restricted to the middle Campanian-latest Maastrichtian (∼77-66 Ma). The recent discovery of a new tyrannosaurid, Lythronax argestes, from the Wahweap Formation of Utah provided new data on early Campanian (∼80 Ma) tyrannosaurids. Nevertheless, the early evolution of Tyrannosauridae is still largely unsampled. We report a new tyrannosaurid represented by an associated skeleton from the lower Campanian Allison Member of the Menefee Formation of New Mexico. Despite fragmentation of much of the axial and appendicular skeleton prior to discovery, the frontals, a metacarpal, and two pedal phalanges are well-preserved. The frontals exhibit an unambiguous autapomorphy and a second potential autapomorphy that distinguish this specimen from all other tyrannosaurids. Therefore, the specimen is made the holotype of the new genus and species Dynamoterror dynastes. A phylogenetic analysis places Dynamoterror dynastes in the tyrannosaurid subclade Tyrannosaurinae. Laser-scanning the frontals and creation of a composite 3-D digital model allows the frontal region of the skull roof of Dynamoterror to be reconstructed.",
    url = "https://doi.org/10.7717/peerj.5749",
    doi = "10.7717/peerj.5749",
    openalex = "W2897729545",
    references = "doi101002ar20982, doi101002ar20983, doi101017s1755691013000261, doi101038nature21700, doi10108002724634200310010947, doi101111cla12160, doi101126science1230492, doi10120637172, doi1015468lnfamn, doi1018814epiiugs2013v36i3002, doi1023073889334, doi102475ajss32313381, doi103133b1940, openalexw3215057009, schwimmer1993late"
}

Present knowledge of Late Triassic tetrapod evolution, including the rise of dinosaurs, relies heavily on the fossil-rich continental deposits of South America, their precise depositional histories and correlations. We report on an extended succession of the Ischigualasto Formation exposed in the Hoyada del Cerro Las Lajas (La Rioja, Argentina), where more than 100 tetrapod fossils were newly collected, augmented by historical finds such as the ornithosuchid Venaticosuchus rusconii and the putative ornithischian Pisanosaurus mertii. Detailed lithostratigraphy combined with high-precision U-Pb geochronology from three intercalated tuffs are used to construct a robust Bayesian age model for the formation, constraining its deposition between 230.2 ± 1.9 Ma and 221.4 ± 1.2 Ma, and its fossil-bearing interval to 229.20 + 0.11/- 0.15-226.85 + 1.45/- 2.01 Ma. The latter is divided into a lower Hyperodapedon and an upper Teyumbaita biozones, based on the ranges of the eponymous rhynchosaurs, allowing biostratigraphic correlations to elsewhere in the Ischigualasto-Villa Unión Basin, as well as to the Paraná Basin in Brazil. The temporally calibrated Ischigualasto biostratigraphy suggests the persistence of rhynchosaur-dominated faunas into the earliest Norian. Our ca. 229 Ma age assignment to Pi. mertii partially fills the ghost lineage between younger ornithischian records and the oldest known saurischians at ca. 233 Ma.

@article{doi101038s41598020678541,
    author = "Desojo, Julia B. and Fiorelli, Lucas E. and Ezcurra, Martín D. and Martinelli, Agustín G. and Ramezani, Jahandar and da Rosa, Átila Augusto Stock and von Baczko, M. Belén and Trotteyn, M. Jimena and Montefeltro, Felipe C. and Ezpeleta, Miguel and Langer, Max C.",
    title = "The Late Triassic Ischigualasto Formation at Cerro Las Lajas (La Rioja, Argentina): fossil tetrapods, high-resolution chronostratigraphy, and faunal correlations",
    year = "2020",
    journal = "Scientific Reports",
    abstract = "Present knowledge of Late Triassic tetrapod evolution, including the rise of dinosaurs, relies heavily on the fossil-rich continental deposits of South America, their precise depositional histories and correlations. We report on an extended succession of the Ischigualasto Formation exposed in the Hoyada del Cerro Las Lajas (La Rioja, Argentina), where more than 100 tetrapod fossils were newly collected, augmented by historical finds such as the ornithosuchid Venaticosuchus rusconii and the putative ornithischian Pisanosaurus mertii. Detailed lithostratigraphy combined with high-precision U-Pb geochronology from three intercalated tuffs are used to construct a robust Bayesian age model for the formation, constraining its deposition between 230.2 ± 1.9 Ma and 221.4 ± 1.2 Ma, and its fossil-bearing interval to 229.20 + 0.11/- 0.15-226.85 + 1.45/- 2.01 Ma. The latter is divided into a lower Hyperodapedon and an upper Teyumbaita biozones, based on the ranges of the eponymous rhynchosaurs, allowing biostratigraphic correlations to elsewhere in the Ischigualasto-Villa Unión Basin, as well as to the Paraná Basin in Brazil. The temporally calibrated Ischigualasto biostratigraphy suggests the persistence of rhynchosaur-dominated faunas into the earliest Norian. Our ca. 229 Ma age assignment to Pi. mertii partially fills the ghost lineage between younger ornithischian records and the oldest known saurischians at ca. 233 Ma.",
    url = "https://doi.org/10.1038/s41598-020-67854-1",
    doi = "10.1038/s41598-020-67854-1",
    openalex = "W3045879460",
    references = "doi101016c20090644421, doi101016jgr201801005, doi101016jquascirev200807009, doi101016s0753396900800026, doi101017cbo9780511612381, doi101017s1755691013000431, doi101038nature22037, doi101073pnas1402369111, doi101080027246342013818546, doi101080027246342013820113, doi101080031155182015994114, doi101098rstb19740001, doi101111j109600311988tb00514x, doi101111j10963642200900631x, doi101111j14679876200800623x, doi101126science1198467, doi101144sp37916, doi1012063521, doi1018814epiiugs2013v36i3002, doi1023071005355, doi1023072413376, doi107717peerj1778"
}

The twelve Gondwanan stratigraphic horizons of India have yielded varied vertebrate fossils. The oldest fossil record is the Endothiodon-dominated multitaxic Kundaram fauna, which correlates the Kundaram Formation with several other coeval Late Permian horizons of South Africa, Zambia, Tanzania, Mozambique, Malawi, Madagascar and Brazil. The Permian-Triassic transition in India is marked by distinct taxonomic shift and faunal characteristics and represented by small-sized holdover fauna of the Early Triassic Panchet and Kamthi fauna. The Middle and Late Triassic saw extensive radiations of the indigenous and living faunas in the form of new temnospondyls, varied archosauromorphs, the basal dinosaurs, non-mammalian cynodonts and mammaliaforms. All the Triassic Gondwanan horizons of India can be correlated with other horizons around the world, resulting in precise biostratigraphic correlation. The Triassic-Jurassic transition in India show marked biotic turnover, which may have resulted from global warming and volcanism. On a Pangaean landscape, the Indian Gondwanan vertebrate assemblages reflect major transformations in vertebrate evolution, global faunal transitions, and constitute important biostratigraphic markers.

@article{doi1018814epiiugs2020020028,
    author = "Bandyopadhyay, Saswati and Ray, Sanghamitra",
    title = "Gondwana Vertebrate Faunas of India: Their Diversity and Intercontinental Relationships",
    year = "2020",
    journal = "Episodes",
    abstract = "The twelve Gondwanan stratigraphic horizons of India have yielded varied vertebrate fossils. The oldest fossil record is the Endothiodon-dominated multitaxic Kundaram fauna, which correlates the Kundaram Formation with several other coeval Late Permian horizons of South Africa, Zambia, Tanzania, Mozambique, Malawi, Madagascar and Brazil. The Permian-Triassic transition in India is marked by distinct taxonomic shift and faunal characteristics and represented by small-sized holdover fauna of the Early Triassic Panchet and Kamthi fauna. The Middle and Late Triassic saw extensive radiations of the indigenous and living faunas in the form of new temnospondyls, varied archosauromorphs, the basal dinosaurs, non-mammalian cynodonts and mammaliaforms. All the Triassic Gondwanan horizons of India can be correlated with other horizons around the world, resulting in precise biostratigraphic correlation. The Triassic-Jurassic transition in India show marked biotic turnover, which may have resulted from global warming and volcanism. On a Pangaean landscape, the Indian Gondwanan vertebrate assemblages reflect major transformations in vertebrate evolution, global faunal transitions, and constitute important biostratigraphic markers.",
    url = "https://doi.org/10.18814/epiiugs/2020/020028",
    doi = "10.18814/epiiugs/2020/020028",
    openalex = "W3012224504",
    references = "doi101007978331968009510, doi101016jgeobios201806004, doi101017s1755691013000376, doi1010800891296320191609957"
}

The Late Triassic (Norian) outcrops of the Malmros Klint Formation, Jameson Land (Greenland) have yielded numerous specimens of non-sauropod sauropodomorphs. Relevant fossils were briefly reported in 1994 and were assigned to Plateosaurus trossingensis. However, continuous new findings of early non-sauropod sauropodomorphs around the globe facilitate comparisons and allow us to now revise this material. Here, the non-sauropod sauropodomorph Issi saaneq gen. et sp. nov. is described based on two almost complete and articulated skulls. The two skulls represent a middle-stage juvenile and a late-stage juvenile or subadult. Issi saaneq differs from all other sauropodomorphs by several unique traits: (1) a small foramen at the medial surface of the premaxilla; (2) an anteroposteriorly elongated dorsoposterior process of the squamosal; (3) a relatively high quadrate relative to rostrum height; (4) a well-developed posterodorsal process of the articular. These features cannot be explained by taphonomy, ontogeny, or intraspecific variation. Issi saaneq shows affinities to Brazilian plateosaurids and the European Plateosaurus, being recovered as the sister clade of the latter in our phylogenetic analysis. It is the northernmost record of a Late Triassic sauropodomorph, and a new dinosaur species erected for Greenland. Issi saaneq broadens our knowledge about the evolution of plateosaurid sauropodomorphs.

@article{doi103390d13110561,
    author = "Beccari, Victor and Mateus, Octávio and Wings, Oliver and Milàn, Jesper and Clemmensen, Lars B.",
    title = "Issi saaneq gen. et sp. nov.—A New Sauropodomorph Dinosaur from the Late Triassic (Norian) of Jameson Land, Central East Greenland",
    year = "2021",
    journal = "Diversity",
    abstract = "The Late Triassic (Norian) outcrops of the Malmros Klint Formation, Jameson Land (Greenland) have yielded numerous specimens of non-sauropod sauropodomorphs. Relevant fossils were briefly reported in 1994 and were assigned to Plateosaurus trossingensis. However, continuous new findings of early non-sauropod sauropodomorphs around the globe facilitate comparisons and allow us to now revise this material. Here, the non-sauropod sauropodomorph Issi saaneq gen. et sp. nov. is described based on two almost complete and articulated skulls. The two skulls represent a middle-stage juvenile and a late-stage juvenile or subadult. Issi saaneq differs from all other sauropodomorphs by several unique traits: (1) a small foramen at the medial surface of the premaxilla; (2) an anteroposteriorly elongated dorsoposterior process of the squamosal; (3) a relatively high quadrate relative to rostrum height; (4) a well-developed posterodorsal process of the articular. These features cannot be explained by taphonomy, ontogeny, or intraspecific variation. Issi saaneq shows affinities to Brazilian plateosaurids and the European Plateosaurus, being recovered as the sister clade of the latter in our phylogenetic analysis. It is the northernmost record of a Late Triassic sauropodomorph, and a new dinosaur species erected for Greenland. Issi saaneq broadens our knowledge about the evolution of plateosaurid sauropodomorphs.",
    url = "https://doi.org/10.3390/d13110561",
    doi = "10.3390/d13110561",
    openalex = "W3209360235",
    references = "doi101073pnas2020778118, doi1034194bullgguv1396681"
}

Abstract Non-archosaur archosauromorphs are a paraphyletic group of diapsid reptiles that were important members of global Middle and Late Triassic continental ecosystems. Included in this group are the azendohsaurids, a clade of allokotosaurians (kuehneosaurids and Azendohsauridae + Trilophosauridae) that retain the plesiomorphic archosauromorph postcranial body plan but evolved disparate cranial features that converge on later dinosaurian anatomy, including sauropodomorph-like marginal dentition and ceratopsian-like postorbital horns. Here we describe a new malerisaurine azendohsaurid from two monodominant bonebeds in the Blue Mesa Member, Chinle Formation (Late Triassic, ca. 218–220 Ma); the first occurs at Petrified Forest National Park and preserves a minimum of eight individuals of varying sizes, and the second occurs near St. Johns, Arizona. Puercosuchus traverorum n. gen. n. sp. is a carnivorous malerisaurine that is closely related to Malerisaurus robinsonae from the Maleri Formation of India and to Malerisaurus langstoni from the Dockum Group of western Texas. Dentigerous elements from Puercosuchus traverorum n. gen. n. sp. confirm that some Late Triassic tooth morphotypes thought to represent early dinosaurs cannot be differentiated from, and likely pertain to, Puercosuchus -like malerisaurine taxa. These bonebeds from northern Arizona support the hypothesis that non-archosauriform archosauromorphs were locally diverse near the middle Norian and experienced an extinction event prior to the end-Triassic mass extinction coincidental with the Adamanian-Revueltian boundary recognized at Petrified Forest National Park. The relatively late age of this early-diverging taxon (Norian) suggests that the diversity of azendohsaurids is underrepresented in Middle and Late Triassic fossil records around the world. UUID: http://zoobank.org/e6eeefd2-a0ae-47fc-8604-9f45af8c1147.

@article{doi101017jpa202249,
    author = "Marsh, Adam D. and Parker, William G. and Nesbitt, Sterling J. and Kligman, Ben T. and Stocker, Michelle R.",
    title = "Puercosuchus traverorum n. gen. n. sp.: a new malerisaurine azendohsaurid (Archosauromorpha: Allokotosauria) from two monodominant bonebeds in the Chinle Formation (Upper Triassic, Norian) of Arizona",
    year = "2022",
    journal = "Journal of Paleontology",
    abstract = "Abstract Non-archosaur archosauromorphs are a paraphyletic group of diapsid reptiles that were important members of global Middle and Late Triassic continental ecosystems. Included in this group are the azendohsaurids, a clade of allokotosaurians (kuehneosaurids and Azendohsauridae + Trilophosauridae) that retain the plesiomorphic archosauromorph postcranial body plan but evolved disparate cranial features that converge on later dinosaurian anatomy, including sauropodomorph-like marginal dentition and ceratopsian-like postorbital horns. Here we describe a new malerisaurine azendohsaurid from two monodominant bonebeds in the Blue Mesa Member, Chinle Formation (Late Triassic, ca. 218–220 Ma); the first occurs at Petrified Forest National Park and preserves a minimum of eight individuals of varying sizes, and the second occurs near St. Johns, Arizona. Puercosuchus traverorum n. gen. n. sp. is a carnivorous malerisaurine that is closely related to Malerisaurus robinsonae from the Maleri Formation of India and to Malerisaurus langstoni from the Dockum Group of western Texas. Dentigerous elements from Puercosuchus traverorum n. gen. n. sp. confirm that some Late Triassic tooth morphotypes thought to represent early dinosaurs cannot be differentiated from, and likely pertain to, Puercosuchus -like malerisaurine taxa. These bonebeds from northern Arizona support the hypothesis that non-archosauriform archosauromorphs were locally diverse near the middle Norian and experienced an extinction event prior to the end-Triassic mass extinction coincidental with the Adamanian-Revueltian boundary recognized at Petrified Forest National Park. The relatively late age of this early-diverging taxon (Norian) suggests that the diversity of azendohsaurids is underrepresented in Middle and Late Triassic fossil records around the world. UUID: http://zoobank.org/e6eeefd2-a0ae-47fc-8604-9f45af8c1147.",
    url = "https://doi.org/10.1017/jpa.2022.49",
    doi = "10.1017/jpa.2022.49",
    openalex = "W4312527876",
    references = "doi101002ar24757, doi1010800891296320171333609"
}

The Late Triassic Dockum Group in northwestern Texas preserves a rich diversity of pseudosuchian taxa, particularly of aetosaurs. In this contribution, we present Garzapelta muelleri gen. et sp. nov., a new aetosaur from the Late Triassic middle Cooper Canyon Formation (latest Adamanian-earliest Revueltian teilzones) in Garza County, Texas, based on an associated specimen that preserves a significant portion of its dorsal carapace. The carapace of G. muelleri exhibits a striking degree of similarity between that of the paratypothoracin Rioarribasuchus chamaensis and desmatosuchins. We quantitatively assessed the relationships of G. muelleri using several iterations of the matrix. Scoring the paramedian and lateral osteoderms of G. muelleri independently results in conflicting topologies. Thus, it is evident that our current matrix is limited in its ability to discern the convergence within this new taxon and that our current character lists are not fully accounting for the morphological disparity of the aetosaurian carapace. Qualitative comparisons suggest that G. muelleri is a Rioarribasuchus-like paratypothoracin with lateral osteoderms that are convergent with those of desmatosuchins. Although the shape of the dorsal eminence, and the presence of a dorsal flange that is rectangular and proportionately longer than the lateral flange are desmatosuchin-like features of G. muelleri, the taxon does not exhibit the articulation style between the paramedian and lateral osteoderms which diagnose the Desmatosuchini (i.e., a rigid interlocking contact, and an anteromedial edge of the lateral osteoderm that overlaps the adjacent paramedian osteoderm).

@article{doi101002ar25379,
    author = "Reyes, William A. and Martz, Jeffrey W. and Small, Bryan J.",
    title = "Garzapelta muelleri gen. et sp. nov., a new aetosaur (Archosauria: Pseudosuchia) from the Late Triassic (middle Norian) middle Cooper Canyon Formation, Dockum Group, Texas, USA, and its implications on our understanding of the morphological disparity of the aetosaurian dorsal carapace",
    year = "2024",
    journal = "The Anatomical Record",
    abstract = "The Late Triassic Dockum Group in northwestern Texas preserves a rich diversity of pseudosuchian taxa, particularly of aetosaurs. In this contribution, we present Garzapelta muelleri gen. et sp. nov., a new aetosaur from the Late Triassic middle Cooper Canyon Formation (latest Adamanian-earliest Revueltian teilzones) in Garza County, Texas, based on an associated specimen that preserves a significant portion of its dorsal carapace. The carapace of G. muelleri exhibits a striking degree of similarity between that of the paratypothoracin Rioarribasuchus chamaensis and desmatosuchins. We quantitatively assessed the relationships of G. muelleri using several iterations of the matrix. Scoring the paramedian and lateral osteoderms of G. muelleri independently results in conflicting topologies. Thus, it is evident that our current matrix is limited in its ability to discern the convergence within this new taxon and that our current character lists are not fully accounting for the morphological disparity of the aetosaurian carapace. Qualitative comparisons suggest that G. muelleri is a Rioarribasuchus-like paratypothoracin with lateral osteoderms that are convergent with those of desmatosuchins. Although the shape of the dorsal eminence, and the presence of a dorsal flange that is rectangular and proportionately longer than the lateral flange are desmatosuchin-like features of G. muelleri, the taxon does not exhibit the articulation style between the paramedian and lateral osteoderms which diagnose the Desmatosuchini (i.e., a rigid interlocking contact, and an anteromedial edge of the lateral osteoderm that overlaps the adjacent paramedian osteoderm).",
    url = "https://doi.org/10.1002/ar.25379",
    doi = "10.1002/ar.25379",
    openalex = "W4390740354",
    references = "doi1010800891296320171333609"
}

Silesaurids (Archosauria: Dinosauriformes) are found in Middle to Upper Triassic deposits across Pangea, but few stratigraphic sections record the evolution of the group in one geographic area over millions of years. Here, we describe silesaurid remains from the oldest of the Upper Triassic stratigraphic sequence from the base of the Dockum Group, from the type locality of the Otischalkian faunachronozone. Isolated limb bones diagnostic of silesaurids include humeri, femora, and tibiae of a seemingly unique Silesaurus-like taxon from the same locality (Otis Chalk Quarry 3). The femora consist of four specimens of different lengths that sample the variation of character states associated with ontogeny, also sampled previously in both silesaurids (e.g., Asilisaurus kongwe and Silesaurus opolensis) and within neotheropods within Dinosauria (e.g., Coelophysis bauri). Our observations of the variation in the silesaurid sample further reinforce the interpretation of high variation of morphological features common in dinosauriforms. Furthermore, we show that overpreparation of bone surfaces has hidden some of this variation in previous interpretations. The tibia growth series shows that the fibular crest of the tibia develops during ontogeny, yet another phylogenetically informative character for dinosaurs and their kin that is at least ontogenetically variable in silesaurids. The presence of silesaurids at the base of the Dockum Group (late Carnian or early Norian) conclusively shows that the group was present near the onset of deposition of Upper Triassic rocks and survived for millions of years in the same geographic area at low latitudes throughout the Late Triassic.

@article{doi101002ar25677,
    author = "Tolchard, Frederick and Perkins, B. and Nesbitt, Sterling J.",
    title = "Silesaurid (Archosauria: Dinosauriformes) remains from the base of the Dockum Group (Late Triassic: Otischalkian) of Texas provide new insights to the North American record of dinosauriforms",
    year = "2025",
    journal = "The Anatomical Record",
    abstract = "Silesaurids (Archosauria: Dinosauriformes) are found in Middle to Upper Triassic deposits across Pangea, but few stratigraphic sections record the evolution of the group in one geographic area over millions of years. Here, we describe silesaurid remains from the oldest of the Upper Triassic stratigraphic sequence from the base of the Dockum Group, from the type locality of the Otischalkian faunachronozone. Isolated limb bones diagnostic of silesaurids include humeri, femora, and tibiae of a seemingly unique Silesaurus-like taxon from the same locality (Otis Chalk Quarry 3). The femora consist of four specimens of different lengths that sample the variation of character states associated with ontogeny, also sampled previously in both silesaurids (e.g., Asilisaurus kongwe and Silesaurus opolensis) and within neotheropods within Dinosauria (e.g., Coelophysis bauri). Our observations of the variation in the silesaurid sample further reinforce the interpretation of high variation of morphological features common in dinosauriforms. Furthermore, we show that overpreparation of bone surfaces has hidden some of this variation in previous interpretations. The tibia growth series shows that the fibular crest of the tibia develops during ontogeny, yet another phylogenetically informative character for dinosaurs and their kin that is at least ontogenetically variable in silesaurids. The presence of silesaurids at the base of the Dockum Group (late Carnian or early Norian) conclusively shows that the group was present near the onset of deposition of Upper Triassic rocks and survived for millions of years in the same geographic area at low latitudes throughout the Late Triassic.",
    url = "https://doi.org/10.1002/ar.25677",
    doi = "10.1002/ar.25677",
    openalex = "W4410190660",
    references = "doi1010800891296320171333609, doi10159000013765202420231248"
}