Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae: Chasmosaurinae): Synonymy Through Ontogeny

@inproceedings{Scannella2010TorosaurusM1,
  title={Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae: Chasmosaurinae): Synonymy Through Ontogeny},
  author={John B. Scannella and John R. Horner},
  year={2010}
}
ABSTRACT Although they have been considered distinct genera for over a century, ontogenetic analyses reveal that Triceratops and “Torosaurus” actually represent growth stages of a single genus. Major changes in cranial morphology—including the opening of parietal fenestrae and the elongation of the squamosals—occur rapidly, very late in Triceratops ontogeny and result in the characteristic ‘Torosaurus’ morphology. This report presents the results of a 10-year field study of the dinosaurs of the… Expand
Ontogenetic and stratigraphic cranial variation in the ceratopsid dinosaur 'Triceratops' from the Hell Creek Formation, Montana
Although they have been considered distinct genera for over a century, ontogenetic analyses reveal that Triceratops and 'Torosaurus' actually represent growth stages of a single genus. Major changesExpand
Torosaurus Is Not Triceratops: Ontogeny in Chasmosaurine Ceratopsids as a Case Study in Dinosaur Taxonomy
TLDR
A well-defined sequence of changes exists in horned dinosaurs: development of cranial ornament occurs in juveniles, followed by fusion of the skull roof in subadults, and finally, the epoccipitals, epijugals, and rostral fuse to the skull in adults. Expand
Anatomy and Taxonomic Status of the Chasmosaurine Ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A
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N. hatcheri is tentatively considered valid, and closely related to Triceratops spp, indicating that species richness for chasmosaurine ceratopsids in the Lance Formation just prior to the Cretaceous-Paleocene extinction was roughly equivalent to that earlier in the Cretsaceous. Expand
Skull ontogeny in Arrhinoceratops brachyops (Ornithischia: Ceratopsidae) and other horned dinosaurs
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This study elucidates the otherwise contentious evolutionary relationships of Arrhinoceratops, and highlights the importance of ontogenetic data for resolving phylogenies when morphological data from adults alone are inadequate. Expand
Ceratopsia increase: history and trends1
The taxonomic history of the Ceratopsia began in 1876 with the description of Monoclonius crassus Cope followed in 1889 by Triceratops horridus Marsh. After a peak of discovery and description in theExpand
‘Nedoceratops’: An Example of a Transitional Morphology
TLDR
The Triceratops, ‘Torosaurus’, and ‘Nedoceratops’ morphologies represent ontogenetic variation within a single genus of chasmosaurine: Tricer atops. Expand
Evolutionary trends in Triceratops from the Hell Creek Formation, Montana
TLDR
This research indicates that the two currently recognized species of Triceratops are stratigraphically separated and that the evolution of this genus likely incorporated anagenetic (transformational) change, which impact interpretations of dinosaur diversity at the end of the Cretaceous and illuminate potential modes of evolution in the Dinosauria. Expand
Is Torosaurus Triceratops? Geometric Morphometric Evidence of Late Maastrichtian Ceratopsid Dinosaurs
TLDR
This new approach confirms the taxonomic status of Torosaurus as well as the comparatively low diversity of ceratopsids at the end of the Maastrichtian in North America. Expand
New information on the rare horned dinosaur Arrhinoceratops brachyops (Ornithischia: Ceratopsidae) from the Upper Cretaceous of Alberta, Canada
Arrhinoceratops brachyops is a poorly understood chasmosaurine ceratopsid from the Upper Cretaceous Horseshoe Canyon Formation of Alberta, previously described on the basis of only a single skull.Expand
Titanoceratops ouranos, a giant horned dinosaur from the late Campanian of New Mexico
Abstract At the end of the Cretaceous, 65.5 million years ago, the giant ceratopsids Triceratops and Torosaurus dominated North America’s dinosaur fauna. The origins of these giant ceratopsids, theExpand
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References

SHOWING 1-10 OF 57 REFERENCES
REDESCRIPTION OF THE CERATOPSID DINOSAUR TOROSAURUS UTAHENSIS (GILMORE, 1946) AND A REVISION OF THE GENUS
TLDR
Associated elements (lower jaws and others), which may pertain to the holotype, are described for the first time; they provide additional information regarding the osteology of this rare chasmosaurine. Expand
Attributes of the Ceratopsian Dinosaur Torosaurus, and New Material from the Javelina Formation (Maastrichtian) of Texas
Abstract A bone bed in the middle part of the Javelina Formation (Maastrichtian) in Texas yielded parts of about 37 identifiable ceratopsid dinosaur bones, mostly appendicular and limb girdleExpand
A CERATOPSID DINOSAUR PARIETAL FROM NEW MEXICO AND ITS IMPLICATIONS FOR CERATOPSID BIOGEOGRAPHY AND SYSTEMATICS
Ceratopsid (horned dinosaur) cranial material is relatively common in the Upper Cretaceous Naashoibito Member of the Kirtland Formation, San Juan Basin, New Mexico. However, the specimens areExpand
Two new horned dinosaurs from the upper Cretaceous Two Medicine Formation of Montana; with a phylogenetic analysis of the Centrosaurinae (Ornithischia: Ceratopsidae)
TLDR
Two new ceratopsid dinosaurs, Einiosaurus procurvicornis and Achelousaurus horneri, are described from the Two Medicine Formation of Montana and suggest an increased rate of evolution that may correlate with the late Campanian transgression of the Bearpaw Sea. Expand
Taxonomic Implications of Relative growth in Lambeosaurine Hadrosaurs
TLDR
A fauna of 3 genera and 12 species of lambeosaurine hadrosaurs (crested duck-billed dinosaurs) from the Oldman Formation of southern Alberta is examined, finding niche differentiation by size among closely related species of large reptiles does not seem to be a feasible strategy. Expand
Species resolution in Triceratops: cladistic and morphometric approaches
TLDR
All available skulls of the ten remaining “species” of Triceratops are placed in one of two species: T. horridus and T. prorsus, invalidating eight of the original ten species. Expand
Two Ornithischian Dinosaurs Renamed: Microceratops Bohlin 1953 and Diceratops Lull 1905
TLDR
The name of the ceratopsian dinosaur Diceratops Lull, 1905 from the Late Cretaceous of United States is a junior homonym of the hymenoptera Diteratops Foerster, 1868, and Diceratus n. Expand
Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications
TLDR
An important implication arising directly from this study is that juvenile and sub-adult centrosaurines are difficult to distinguish taxonomically at the specific level. Expand
THE SMALLEST KNOWN TRICERATOPS SKULL: NEW OBSERVATIONS ON CERATOPSID CRANIAL ANATOMY AND ONTOGENY
TLDR
The discovery of the smallest Triceratops skull provides a new ontogenetic end member for the earliest stage of ceratopsid cranial development and shows that the cranial ornamentation of the frill and the postorbital horns were not restricted to adults, but began at an early age in this species. Expand
Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)
TLDR
An increase in tooth width, accompanied by loss of tooth positions, and a global shift from an immature gracile to a mature robust morphotype in the craniofacial skeleton typifies the ontogenetic changes in T. rex. Expand
...
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...