University of Alberta Individual and ontogenetic variation in theropod dinosaur teeth: a case study of Coelophysis bauri (Theropoda: Coelophysoidea) and implications for identifying isolated theropod teeth. by Lisa Glynis Buckley A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Systematics and Evolution Department of Biological Sciences Edmonton, Alberta Spring 2009 Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 OttawaONK1A0N4 Canada Canada Your Tile Votre reference ISBN: 978-0-494-54656-7 Our file Notre reference ISBN: 978-0-494-54656-7 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lntemet, prefer, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. •+• Canada ABSTRACT Isolated theropod teeth are useful data for paleogeographical and paleoeco- logical studies, though ambiguous tooth morphotypes are frequently recovered from Late Cretaceous microfossil localities. It is not known if these morphotypes result from individual or ontogenetic variation. Eight hundred forty-eight teeth from twenty- three skulls of the Late Triassic (Carnian - Norian) theropod Coelophysis bauri from Ghost Ranch, New Mexico, were analyzed using statistical and multivariate analy­ ses. Principle component and discriminant analyses show that, despite heterodontic morphology, teeth from premaxillae, maxillae, and dentaries, and teeth from small (juvenile) and large (adult) skulls occupy a similar morphospace and would not be mistakenly identified as newtaxa. Teeth with longitudinal ridging only occur in small (juvenile) skulls also occupy the same morphospace as non-ridged teeth, and may be an ontogenetically controlled character of tooth morphology in C. bauri. Ridged tooth morphotypes from Late Cretaceous microfossil localities may be ontogenetic variants from known theropod taxa. ACKNOWLEDGMENTS I wish to extend my thanks to the following for their aid in the completion of this study: my advisor Dr. Philip Currie (University of Alberta) and committee mem­ bers Dr. Michael Caldwell (University of Alberta) and Dr. Donald Brinkman (Royal Tyrrell Museum of Palaeontology) for their discussions and critiques of this study; Dr. Eva Koppelhus for her aid in coordinating my thesis activities; and Eric Snively (University of Alberta) and Julia Sankey (University of California - Stanislaus) for their discussions on theropod tooth morphology. I also wish to thank Mark Norell and Carl Mehling (American Museum of Natural History), Ken Carpenter and Logan Ivy (Denver Museum of Nature), David Gillette and Janet Whitmore-Gillette (Museum of Northern Arizona), Spencer Lucas, Justin Speilmann, and Larry Rhinehart (New Mexico Museum of Natural History), and Andy Neuman and Brandon Strilisky (Royal Tyrrell Museum of Palaeontology) for access to their institution's collections and for their hospitality during my visits. This study would not have been completed were it not for the many discus­ sions and unwavering support, encouragement, and patience of my husband and colleague Richard T M'Crea. I also wish to thank my family (parents Tom and Su­ san, sisters Cynthia and Sally, grandparents Doreen and Ted Burger) and my husband's family (Raymond, Marlene, Julie, and Kari) for support and encourage­ ment. I also wish to thank my great-aunt Molly Gresley-Jones for inspiring in me an interest in natural history at an early age. Funding was made available through the University of Alberta (Dr. Philip Currie's Lab, Faculty of Graduate Studies and Research Queen Elizabeth II Scholar­ ship, Department of Biological Sciences Graduate Teaching Assistantship), the Jurassic Foundation, and the Dinosaur Research Institute. I also wish to thank the Tumbler Ridge Museum Foundation for employing me during my graduate studies and for their drive and passion to protect British Columbia's fossil heritage. TABLE OF CONTENTS 1.0 INTRODUCTION 1 1.1 Shed theropod teeth in paleontology. 1 1.2 Variation in tooth morphology of tetrapods 2 1.3 Documentation of theropod tooth morphology 3 1.4 Individual variation in theropod teeth 6 1.5 Ontogenetic variation in theropod teeth 7 1.6 Wrinkles, ridges, and tooth crowns 8 1.7 Purpose of study 9 1.8 Institutional abbreviations 9 2.0 TAXONOMIC HISTORY OF COELOPHYSIS BAURI 11 2.1 History of Coelophysis bauri 11 2.2 Taxonomic history of Coelophysis bauri. 11 2.3 Colbert (1989) description of C. bauri dental formulae and morphology 12 3.0 MATERIALS AND METHODS 14 3.1 Specimen variables affecting data collection 14 3.2 Equipment used for data collection 15 3.3 Data collected 15 3.4 Description of statistical analyses 17 3.5 Description of multivariate analyses 18 3.6 Measurement and anatomical abbreviations 19 4.0 RESULTS 20 4.1 Description of C. bauriteeth 20 4.1.1 Overal description 20 4.1.2 Premaxillay and anterior dentary teeth 22 4.1.3 Mid-tooth row maxillary and dentary teeth 23 4.1.4 Posterior maxillary and dentary teeth 25 4.1.5 Longitudinal ridged teeth in C. bauri. 27 4.2 Individual variation in teeth of C. bauri. 28 4.3 Patterns in C. bauritooth replacement 31 4.4 Regression results 33 4.5 Multivariate results 36 4.5.1 Normality and specimen variation 36 4.5.2 Separating teeth from premaxillae, maxillae, and dentaries 39 4.5.3 Separating teeth from large (adult) and small (juvenile) specimens 43 4.5.4 Separating anterior and posterior tooth positions 45 4.5.5 Multivariate results of denticle measurements 48 4.6 Multivariate comparison of teeth from C. bauri and Allosaurus sp 50 SYSTEMATIC PALEONTOLOGY. 53 5.1 Revised description of Coelophysis bauri 53 DISCUSSIONS AND CONCLUSION 55 6.1 Amendment to Colbert (1989) description of C. bauri dentition 55 6.1.1 Revised dental formula for observed C. bauri specimens 55 6.1.2 Premaxillary teeth and denticulate carinae 55 6.2 Sexual variation and tooth morphology in C. bauri 56 6.3 Variation and heterodonty in C. bauri 57 6.4 Allometry and C. bauriteeVh 57 6.5 Ontogenetic change and C. bauriteeth 58 6.6 Longitudinally ridged tooth crowns and ontogeny 60 6.6.1 Longitudinally ridged teeth in C. bauri. 60 6.6.2 Longitudinally ridged teeth in Ceratosauria 61 6.6.3 Longitudinally ridged teeth in Theropoda 62 6.6.4 Functionality of longitudinally ridged tooth crowns 63 6.7 Implications of dental variation in C. bauri for shed theropod tooth identification 64 6.8 Conclusions 68 6.8.1 Updated description of C. bauri dentition 68 6.8.2 Potential variation in shed theropod tooth morphology 69 7.0 REFERENCES 71 APPENDIX: Data collected from Coelophysis bauri skulls SV LIST OF TABLES Table 1.1: Methodology and description for shed theropod tooth meaurements 5 Table 3.1: List of repositories with Ghost Ranch Coelophysis quarry blocks 12 Table 4.1: Univariate statistics on C. bauri tooth measurement s for tooth bearing elements 21 Table 4.2: Skulls with longitudinally ridged teeth in C. bauri sample size series from Figure 2 23 Table 4.3: Reduced major axis (RMA) results for bivariate comparisons on tooth and skull measurements of C. bauri 31 Table 4.4: Shapiro-Wilks normality test for C. bauri sample 33 Table 4.5: Variable loadings for principle component analysis on whole C. bauri sample 37 Table 4.6: Principle component analysis results from C. bauri dataset interalveolar distance removed 39 Table 4.7: Discriminant anlysis results of C.bauri comparisons and percent of teeth correctly identified 43 Table 4.8: Principle component analysis percent variance results on C. bauri denticle measurements 47 LIST OF FIGURES Figure 1.1: Graphical description of theropod tooth measurements in study. 4 Figure 3.1: Sample ontogenetic series for whole C. bauri skulls in study 16 Figure 4.1: C. bauri specimen NMMNH P-42579 tooth IM5 anterior carina denticles, labial view. 22 Figure 4.2: C. bauri specimen AMNH 7240 right premaxillary tooth P3 showing denticles on posterior carina 23 Figure 4.3: C. bauri specimen RTMP 1984.63.1-1 left lateral view showing longitudinally ridged maxillary teeth 24 Figure 4.4: C. bauri specimen NMMNH P-42200 left lateral view of longitudinally ridged premaxillary, maxillary, and dentary teeth 25 Figure 4.5: C. bauri specimen MNAV3318 premaxilla and anterior dentary, rostral view, showing longitudinally ridged premaxillary teeth 26 Figure 4.6: Positional variation in FABLand crown basal width (CBW) for all C.