Book contents
- Frontmatter
- Contents
- List of contributors
- Foreword: Charles Mortram Sternberg and the Alberta Dinosaurs
- Preface
- List of institutional abbreviations
- Introduction: on systematics and morphological variation
- I Methods
- II Sauropodomorpha
- III Theropoda
- 5 Variation in theory and in theropods
- 6 Variation in Coelophysis bauri
- 7 Morphological variation in small theropods and its meaning in systematics: evidence from Syntarsus rhodesiensis
- 8 Theropod teeth from the Judith River Formation of southern Alberta, Canada
- 9 The systematic position of Baryonyx walkeri, in the light of Gauthier's reclassification of the Theropoda
- 10 Variation in Tyrannosaurus rex
- IV Ornithopoda
- V Pachycephalosauria
- VI Ceratopsia
- VII Stegosauria
- VIII Ankylosauria
- IX Footprints
- Summary and prospectus
- Taxonomic index
6 - Variation in Coelophysis bauri
Published online by Cambridge University Press: 07 September 2010
- Frontmatter
- Contents
- List of contributors
- Foreword: Charles Mortram Sternberg and the Alberta Dinosaurs
- Preface
- List of institutional abbreviations
- Introduction: on systematics and morphological variation
- I Methods
- II Sauropodomorpha
- III Theropoda
- 5 Variation in theory and in theropods
- 6 Variation in Coelophysis bauri
- 7 Morphological variation in small theropods and its meaning in systematics: evidence from Syntarsus rhodesiensis
- 8 Theropod teeth from the Judith River Formation of southern Alberta, Canada
- 9 The systematic position of Baryonyx walkeri, in the light of Gauthier's reclassification of the Theropoda
- 10 Variation in Tyrannosaurus rex
- IV Ornithopoda
- V Pachycephalosauria
- VI Ceratopsia
- VII Stegosauria
- VIII Ankylosauria
- IX Footprints
- Summary and prospectus
- Taxonomic index
Summary
Abstract
The large series of skeletons and partial skeletons of Coelophysis bauri collected from the Upper Triassic Chinle Formation at Ghost Ranch, New Mexico, affords an opportunity to study the ontogeny, individual variation, and possible sexual dimorphism in this species. Although truly small specimens have not been found in the deposit, it is possible to follow an incomplete growth series in this dinosaurian species involving a threefold increase in linear dimensions. By working back from this partial sequence, it is estimated that there was probably between a ten to fifteenfold increase in size from hatchling to adult, during which there were proportional changes in the size of the orbit, length of the neck, and length of the hind limb and some changes in skull proportions. Substantive differences are to be seen in individual variations, which are especially marked between two adult specimens of approximately the same size. One of these specimens has a larger skull, a longer neck, and a smaller forelimb than the other, and is further differentiated by fusion of the sacral vertebrae, not seen in its counterpart. These differences may be an expression of sexual dimorphism. A variation of fusion within the skeleton is especially marked in the ankle of Coelophysis, particularly as seen in the size and solidity of the ascending process of the astragalocalcaneum, the fusion of this bone to the tibia, and the fusion of the second and third distal tarsals to their respective metatarsals.
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- Information
- Dinosaur SystematicsApproaches and Perspectives, pp. 81 - 90Publisher: Cambridge University PressPrint publication year: 1990
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