A revision of the Ceratopsia or horned dinosaurs

Vene, Clara Mae. Le; Lull, Richard Swann

doi:10.5962/bhl.title.5716

Cited by 73 publications

(121 citation statements)

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“…Whether or not these taxa were largely biogeographically separated or represented ontogenetic variants or sexual dimorphs within a single species has remained unresolved (8,10,12,(15)(16)(17)(18). A record of the stratigraphic distribution of Triceratops from the Upper Cretaceous Lance Formation of Wyoming compiled by Lull (19,20) suggested that these taxa overlap stratigraphically. However, this assessment was likely based on limited stratigraphic data (15) and "the precise stratigraphic placement of these specimens can no longer be established" (ref.…”

mentioning

confidence: 99%

Evolutionary trends inTriceratopsfrom the Hell Creek Formation, Montana

Scannella

Fowler

Goodwin

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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The placement of over 50 skulls of the well-known horned dinosaur Triceratops within a stratigraphic framework for the Upper Cretaceous Hell Creek Formation (HCF) of Montana reveals the evolutionary transformation of this genus. Specimens referable to the two recognized morphospecies of Triceratops, T. horridus and T. prorsus, are stratigraphically separated within the HCF with the T. prorsus morphology recovered in the upper third of the formation and T. horridus found lower in the formation. Hypotheses that these morphospecies represent sexual or ontogenetic variation within a single species are thus untenable. Stratigraphic placement of specimens appears to reveal ancestor-descendant relationships. Transitional morphologies are found in the middle unit of the formation, a finding that is consistent with the evolution of Triceratops being characterized by anagenesis, the transformation of a lineage over time. Variation among specimens from this critical stratigraphic zone may indicate a branching event in the Triceratops lineage. Purely cladogenetic interpretations of the HCF dataset imply greater diversity within the formation. These findings underscore the critical role of stratigraphic data in deciphering evolutionary patterns in the Dinosauria.T he Hell Creek Project (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), a multiinstitutional survey of the fauna, flora, and geology of the Upper Cretaceous Hell Creek Formation (HCF), provides insights into the paleobiology and evolution of the last nonavian dinosaurs (1). Triceratops (Ceratopsidae: Chasmosaurinae) is the most abundant dinosaur in the HCF; >50 skulls, including previously unknown or rare growth stages, have been collected throughout the entire formation (spanning ∼1-2 million y) (2) over the course of the Hell Creek Project (1, 3-5). The combination of a stratigraphically controlled robust sample from the entire ∼90-m-thick HCF and identification of ontogenetic stages makes Triceratops a model organism for testing hypotheses proposed for the modes of dinosaur evolution (e.g., refs. 6-8).Since its initial discovery (9), as many as 16 species of Triceratops were named based on variations in cranial morphology (10, 11). Forster (12) recognized only two species, Triceratops horridus and Triceratops prorsus, based on cranial features including differences in relative length of the postorbital horn cores (long in T. horridus and shorter in T. prorsus), morphology of the rostrum (elongate in T. horridus and shorter in T. prorsus), and closure of the frontoparietal fontanelle (sensu Farke) (13) (open in T. horridus and closed in T. prorsus). Marsh initially distinguished these two species by the morphology of the nasal horn (14); the type specimen of T. horridus possesses a short, blunt nasal horn whereas the nasal horn in T. prorsus is elongate. Whether or not these taxa were largely biogeographically separated or represented ontogenetic variants or sexual dimorphs within a single species has remained unresolved (8,10,12,(15)(16)(...

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mentioning

confidence: 99%

Evolutionary trends inTriceratopsfrom the Hell Creek Formation, Montana

Scannella

Fowler

Goodwin

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The anteroposteriorly broad, blade-like neural spines become more elongate toward the sacrum. The neural spine and postzygapophyses of the last dorsal vertebra (D12) appear to be fused to that of the first dorsosacral, but the centra of these two vertebrae show no evidence of co-ossification, as in one specimen of Centrosaurus (YPM 2015, Lull 1933.…”

Section: Dorsal Vertebrae and Ribsmentioning

confidence: 98%

“…The left lateral surfaces of the vertebrae are covered with cauliflower-shaped growths. At least one pathology has been reported in the cervical region of ceratopsids (Lull 1933), but this is limited to simple fusion of two vertebrae of otherwise normal appearance. The centrum of the ninth cervical is articulated closely to that of C8, to which it may be fused, but otherwise, this vertebra exhibits no obvious abnormalities.…”

Section: Cervical Vertebrae and Ribsmentioning

confidence: 99%

“…The incomplete synsacrum includes two dorsosacrals, four sacral vertebrae bearing stout sacral ribs ('parapophyses' of Hatcher et al, 1907 andLull, 1933), two complete caudosacrals, and the anterior half of the third caudosacral (Figs. 9, 11).…”

Section: Synsacrummentioning

confidence: 99%

“…These ribs project posterolaterally, and expand distally to form the anterior portion of the buttress supporting the medial surface of the acetabular bar. A partial transverse process ('diapophysis' of Hatcher et al 1907 andLull 1933) is preserved only on the left side of the first sacral vertebra. A bony septum originating from the dorsal surface of the sacral rib sweeps posterodorsally to support the underside of this transverse process.…”

Section: Sacral Vertebrae and Ribs: Each Sacral Centrum Ismentioning

confidence: 99%

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The postcranial skeleton of Vagaceratops irvinensis (Dinosauria, Ceratopsidae)

Holmes

2014

Vert. Anat. Morph. Palaeo.

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Abstract:The postcranial skeleton of Vagaceratops (= Chasmosaurus) irvinensis (CMN 41357), lacking only the tail, most of the left front and left hind limbs, and portions of the pelvis, is preserved in articulation. It is one of the most complete, best articulated ceratopsid skeletons known. Both the manus and vertebral column exhibit conspicuous pathologies, possibly an indication of advanced age at the time of death. The vertebral column comprises a syncervical, six additional cervical vertebrae, and 12 dorsals. A partial synsacrum is represented by two dorsosacrals, four sacrals, two caudosacrals, and a partial third caudosacral centrum. The ribcage, although crushed, is nearly complete. The sternum is unusually wide compared with other ceratopsids. As in other chasmosaurines, the humerus bears a prominent deltopectoral crest that forms the anterior edge of the broad, rectangular proximal humeral expansion. The medial tuberosity is separated from the dorsal surface of the humerus by a distinct notch. The insertion for the latissimus dorsi is conspicuous. The deltopectoral crest extends a full half of the distance to the distal end of the humerus. Epipodials of the forelimb are relatively short compared to the corresponding propodial. The ulna has a long, distinctly triangular olecranon, broadly rounded anterolateral process, prominent medial process, and a deeply concave trochlear notch. The terminal phalanges on the fourth and fifth manual digits are relatively large, and unlike other ceratopsids have distinct distal (possibly articular) facets. The fourth trochanter of the femur is relatively proximal in position. This study and other recent studies of ceratopsid postcrania suggest that potentially useful taxonomic variation is present in the number of dorsosacrals, size of the groove on the ventral surface of the sacrum, morphology of the last dorsal and dorsosacral ribs, morphology of the scapula and proximal expansion of the humerus, morphology of the ulna, ratio of humerus/epipodium, morphology of the fifth manual digit, and position of the fourth trochanter of the femur.

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Evaluation of Long Bone Surface Textures as Ontogenetic Indicators in Centrosaurine Ceratopsids

Tumarkin‐Deratzian

2009

The Anatomical Record

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The search for criteria for aging non-mammalian fossil vertebrates has preoccupied paleobiologists in recent years. Previous studies of the long bones of pterosaurs and modern and subfossil birds as well as of cranial material of centrosaurine ceratopsid dinosaurs have documented variations in surface textures that seem to be ontogenetically related. In this study, long bones from the centrosaurine ceratopsid genera Centrosaurus, Einiosaurus, and Pachyrhinosaurus are examined to test the hypothesis that changes in bone surface textures and reduction of surface porosity could be correlated with size (and presumably age) classes, as has been previously documented in pterosaurs and birds. The data set includes 141 bones representing all six long bone elements, collected from monodominant centrosaurine bone beds. Bone surface patterns are documented by macroscopic visual examination, and a sequence of five texture classes ordered by decreasing surface porosity is described based on the common distributions of these patterns. Calculations of Spearman's rank correlation coefficients reveal significant correlations between texture class and size. The smallest bones are invariably associated with porous midshaft textures that grade to fibrous and long-grained patterns proximally and distally [Texture Class (TC) 1]. Post-hoc analysis after Kruskal-Wallis ANOVA on ranks confirms that the mean size of TC1 bones is, in most cases, significantly different than the mean size of bones in other texture classes. Results of this study suggest the presence of an ontogenetic surface textural signal in centrosaurine long bones; however, comparison of texture classes with size-independent maturity criteria is needed to clarify further the potential ontogenetic significance of higher texture classes. Anat Rec, 292:1485Rec, 292: -1500Rec, 292: , 2009. V V C 2009 Wiley-Liss, Inc.

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A revision of the Ceratopsia or horned dinosaurs

Cited by 73 publications

References 2 publications

Evolutionary trends inTriceratopsfrom the Hell Creek Formation, Montana

Evolutionary trends inTriceratopsfrom the Hell Creek Formation, Montana

The postcranial skeleton of Vagaceratops irvinensis (Dinosauria, Ceratopsidae)

Evaluation of Long Bone Surface Textures as Ontogenetic Indicators in Centrosaurine Ceratopsids

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