Morphological Correlates of Locomotion in Anurans: Limb Length, Pelvic Anatomy and Contact Structures A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Masters of Science Verne F. H. Simons June 2008 2 This thesis titled Morphological Correlates of Locomotion in Anurans: Limb Length, Pelvic Anatomy and Contact Structures by VERNE F. H. SIMONS has been approved for the Department of Biological Sciences and the College of Arts and Sciences ______________________________________________ Nancy J. Stevens Assistant Professor of COM-Biomedical Sciences ______________________________________________ Benjamin M. Ogles Dean, College of Arts and Sciences 3 ABSTRACT Simons, Verne F. H., M.S., June 2008, Biological Studies Morphological Correlates of Locomotion in Anurans: Limb Length, Pelvic Anatomy and Contact Structures (87 pp.) Director of Thesis: Nancy J. Stevens This study examines morphological features of the postcranial skeleton in a sample of modern anurans of known locomotor style within the context of a recent phylogenetic hypothesis. Non-destructive methods for collecting skeletal morphometric data from alcohol preserved anuran specimens are herein proposed and tested. Analysis of covariance (ANCOVA) is used to compare morphological structures taking into account differences in body size (SVL) among taxa. Results of this study differ from previous studies in that the patterns of morphological correlates in anurans may not span the entire anuran clade, but are identifiable within phylogenetically focused comparisons. Manus size was predicted to be larger in arboreal than non arboreal anurans, a pattern supported by comparisons within the family Hylidae, and in the derived group Natatanura. Arboreal bufonid species exhibit wider sacra and longer fore- and hind limbs relative to SVL than do terrestrial species. natatanurans capable of long distance jumping exhibit a larger pes (wider and longer) relative to SVL than do arboreal species. Sacral diapophyseal angle (SDA) provides a method of separating walking/running species from all other locomotor groups examined with the exception of members of the strictly aquatic family Pipidae. 4 Fossil anuran specimens recently discovered in Oligocene deposits in the Rukwa Rift Basin of Tanzania preserve pelvic anatomy associated with forceful jumping in modern forms. An estimated sacral diapophyseal angle (SDA) for RRBP 04101 of 21.409° is consistent with this locomotor assessment. Approved:_____________________________________________________________ Nancy J. Stevens Assistant Professor of COM-Biomedical Sciences 5 To my family, thank you all for everything. 6 ACKNOWLEDGEMENTS I would like to thank Dr. Steven Howard and the department of African Studies for two years of funding. Dr. Barry Clarke of the Natural History Museum, London, Laura Abraczinskas and Dr. Mike Gottfried of the Michigan State University Museum, Division of Natural History, Steve Rogers and Dr. Amy Henrici of the Carnegie Museum of Natural History, Greg Schneider of the University of Michigan Museum of Zoology, Alan Resetar, Maureen Kearney and Harold Voris Division of Amphibians and Reptiles Field Museum of Natural History, Chicago, Dr. Bob Hikida, Dr. Joe Eastman, Eric McElroy, Sifa Ngasala, Dr. Eric Roberts, Dr. Anna Mari Baez, Dr. Larry Witmer, David Blackburn, Dr. Zbyněk Roček, Mike Jorgensen, The department of Biological Sciences, Ohio University. I would also like to thank my advisor, Dr. Nancy Stevens, and my committee members, Dr. Scott Moody, Dr. Patrick O’Connor, and Dr. Susan Williams. 7 TABLE OF CONTENTS Page Abstract................................................................................................................................3 Dedication…………………………………………………………………………………4 Acknowledgments................................................................................................................6 List of Tables.......................................................................................................................9 List of Figures....................................................................................................................10 Introduction........................................................................................................................11 Anuran Limb Proportions and Locomotor Style...............................................................14 The Anuran Pectoral Girdle……………………...............................................................15 The Anuran Pelvic Girdle..................................................................................................18 Type I.....................................................................................................................19 Type II (A and B) ..................................................................................................20 Contact Structures in Anurans...........................................................................................24 Hypotheses Considered in This Study...............................................................................24 Materials and Methods.......................................................................................................28 Study Sample.....................................................................................................................28 Measurement Types...........................................................................................................31 Skeletal Specimens............................................................................................................31 Wet Specimens...................................................................................................................31 Radiograph Specimens.......................................................................................................35 Ilio-Sacral Types and Sacral Diapophyseal Angle............................................................40 Analysis of Covariance......................................................................................................41 Analysis of Variance..........................................................................................................43 Narrow Allometric Comparisons.......................................................................................43 Reduced Major Axis Regression.......................................................................................44 Results................................................................................................................................45 Sacral Diapophyseal Angle................................................................................................48 Discussion..........................................................................................................................55 Limb Length Relative to Locomotor Mode.......................................................................55 Natatanura…..........................................................................................................56 Bufonidae…….......................................................................................................56 Hylidae...................................................................................................................57 Contact Structure Size Relative to Locomotor Mode........................................................58 Natatanura…..........................................................................................................58 8 Bufonidae…….......................................................................................................61 Hylidae...................................................................................................................63 Pelvic Dimensions Relative to Locomotor Mode..............................................................64 Natatanura…..........................................................................................................65 Bufonidae…….......................................................................................................70 Hylidae...................................................................................................................73 Leptodactylidae......................................................................................................74 Applying Morphological Correlates of Locomotion to Fossil Anurans............................74 Conclusions………............................................................................................................77 Literature Cited..................................................................................................................81 Appendix: Precision and accuracy of measurement methods…………...……….............87 9 LIST OF TABLES Page Table 1.(Taxa included in study with locomotor habit)...….……………………………29 Table 2.(Measurements used in study)……...……............…………………………...…32 Table 3.(Descriptive statistics for skeletal and wet measurement methods)……….....…35 Table 4.(Descriptive statistics for selected radiographs)………......………….….......... 39 Table 5.(Log10 Reduced major axis regressions of linear measurements on SVL)........ 44 Table 6.(Sacral diapophyseal angles)…..............................……......………………........49 10 LIST OF FIGURES Page Figure 1.(Cladogram with locomotor categories).……………....………………………12 Figure 2.(Cladogram