Osteology and Phylogeny of Oviparous Cyprinodont Fishes (Order Cyprinodontiformes) By RAM PRAKASH SETHI A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA January, I960 ACKNOWLEDGMENTS It has been a long cherished dream of mine to be able to pursue graduate studies in the United States. For making this dream come true by providing me a Graduate Assistantship, I am extremely grateful to the Biology Department and the Graduate School of the University of Florida. The assistantship not only helped me financially and academically but also enabled me to come in contact with many friendly American students with whom I had the opportunity of exchanging ideas on numerous topics. Although lacking appropriate words to express the debt of gratitude which I owe to Dr. John D. Kilby, present chairman, and to Dr. Arnold B. Grobman, ex-chairman of my committee, I wish to thank them both for constant guidance and encouragement during the course of this study. Dr. Kilby originally suggested this problem to me and always answered my numerous questions most sympathetically while Dr. Grobman constantly stimulated me to enlarge its horizons. I also wish to thank the other members of my committee, Drs. Lewis Berner, Walter Auffenberg, Ernest S. Ford, and Howard K. Wallace for numerous courtesies, continued interest in my work, and valuable encouragement. Much of the material for this study was obtained from various institutions and a number of individuals have made available specimens or information to me. For such generous help, I am deeply obliged to Drs. Curt Kosswig, Zoologisches Staatsinstitut und Zoologisches Museum, Hamburg, ¥. Germany} E. Trewavas, British Museum, London, England) ii J. L. B. Smith and R. A. Jubbs, Rhodes University, Grahamstown, South Africa} J. J. Hoederaan, Zoologisch Museum, Amsterdam, Netherlands; James E. Bohlke, Academy of Natural Sciences of Philadelphia} L. P. Schultz, William R. Taylor, 0. A. Cooper, Daniel M. Cohen and Ernest A. Lachner, United States National Museum j William Follett, California Academy of Sciences} Clark Hubbs, University of Texas} Royal D. Suttkus, Tulane University; Caryl P. Haskins, Carnegie Institution of Washington! Donn E. Rosen, Genetics Laboratory, American Museum of Natural History; Margaret Storey and George S. Myers, Stanford University} Howard E. Evans, Cornell University} and Robert R. Miller, University of Michigan. I am also obliged to Drs. Carl L. Hubbs, Scripps Institution of Ocean- ography, and Luis Rene Rivas, University of Miami, for sending to me several papers pertinent to my problem. I am grateful to Mr. Herbert R. Axelrod, Publisher, Tropical Fish Hobbyist, for sending to me many Kodachrome transparencies of cyprinodonts as a special gift. To Drs. Robert R. Miller, Donn E. Rosen, Pierce Brodkorb, and Coleman J. Goin I am especially grateful for answering many questions about my research work and for taking continuous interest in the problems which arose. Thanks are also due to Miss Esther Coogle for help in labeling the figures which are included in this study. For encouragement, for stimulating discussion, and for numer- our courtesies, I am deeply indebted to most of the faculty and the graduate students in the Biology Department at the University of Florida. iv To the Graduate School I am grateful for financial assistance which facilitated my trip to the Genetics Laboratory of the American Museum of Natural History, to study some of the cleared and stained specimens of Dr. Donn E, Rosen and to discuss with him many problems of common Interest. This assistance also enabled me to visit the United States National Museum, where I examined material and arranged for loans. To Dr. Olive I. Reddick, Executive Secretary of the United States Educational Foundation in India, and to the Institute of International Education, Washington, I am indebted for a Fulbright Travel Grant without which my coming to the University of Florida would have been delayed considerably. I am also thankful to the Government of Uttar Pradesh, India, for a small loan for my studies abroad and to the managing committee of Agra College, Agra, India, for sanctioning a leave of absence. TABLE OF CONTENTS Page ACKNOWLEDGMENTS ii LIST OF TABLES viii LIST OF FIGURES ix INTRODUCTION 1 Taxonomic Background 4 Materials and Methods ....... 21 GROUP I 28 Composition, Range, and Habitat 28 Osteology 29 Summary of Significant Osteological Characters of Group I 70 GROUP II 75 Composition, Range, and Habitat 73 Osteology 73 Summary of Significant Osteological Characters of Group II 78 RELATIONSHIPS OF GROUPS I AND II 81 GROUP III 89 Composition, Range, and Habitat . 89 Osteology 91 Summary of Significant Osteological Characters of Group HI 103 Relationships of Group IH 105 Evolutionary Trends within Group III 109 Relationships of Empetrichthys 113 t vi TABLE OF CONTENTS—Continued Page GROUP IV 116 Composition, Range, and Habitat 116 Osteology .......... 116 Summary of Significant Osteological Characters of Group IV 119 Relationships of Group IV 120 GROUP V 125 Composition, Range, and Habitat 123 Osteology 126 Summary of Significant Osteological Characters of Group V 154 Relationships of Group V 157 GROUP VI 140 Composition and Range 140 Osteology 141 Summary of Significant Osteological Characters of Group VI 144 Relationships of Group VI 146 Relationships and Taxonomy of Lamprichthys tanganicanus . 151 GROUP VII . 155 Composition and Range 155 Osteology 155 Summary of Significant Osteological Characters of Group VII 158 Relationships of Group VII 161 GROUP VHI 165 Composition and Range 165 Osteology 165 Summary of Significant Osteological Characters of Group VHI . 166 Relationships of Group VIII 168 vii TABLE OF CONTENTS—Continued Page DISCUSSION AND SUMMARY 172 Major Osteological Characteristics of Oviparous Cyprinodonts ...... 17S Osteological Features Peculiar to Different Groups ....... 174 Cyprinodont Paleontology 182 Ancestral Cyprinodont Stock 187 Evolutionary Trends 191 Taxonomic Implications 195 Dendrogram Showing the Relationship of Cyprinodont Fishes (tentative arrangement) . 196 Synopsis of the Families of Oviparous Cyprinodonts 204 CONCLUSIONS AND RECOMMENDATIONS 207 EXPLANATION OF ABBREVIATIONS USED IN FIGURES 218 FIGURES 224 LITERATURE CITED 267 BIOGRAPHICAL SKETCH 275 LIST OF TABLES Table Page 1. Vertebral Counts for Seven Species of Group I Cyprinodonts ......... 60 2. Dorsal Fin Ray Counts in Five Species of Group I Cyprinodonts ............ 65 S. Anal Fin Ray Counts for Five Species of Group I Cyprinodonts 66 4. Pelvic Fin Ray Counts for Five Species of Group I Cyprinodonts 67 5. Pectoral Fin Ray Counts for Five Species of Group I Cyprinodonts 70 6. Comparison of New World Genera (Group I) and Old World Genera (Group II) of Cyprinodonts 87 7. Comparison of Tooth Structure and Arrangement of Jaw Teeth in Several Species of Group III Cyprinodonts ..... 99 8. Number of Branch! ostegal Rays in Selected Species of Group III 100 9. Osteological Differences Between Empetrichthys and Orestias . 115 viii t LIST OF FIGURES Figure Page 1. Cyprlnodon v. variegatus : head skeleton (lateral~view). 225 2. Cualac tessellatus : A, head skeleton (lateral view); E7~single tooth 226 5. Cyprlnodon v. variegatus , skull i A, dorsal view; B, ventral view 226 4. Cyprlnodon v. variegatus, skull: A, posterior view, B, side view 227 5. Occipital region and first three vertebrae A, Cyprinodon v. variegatus ; B, Cualac tessellatus 228 6. Cyprlnodon v. variegatus t A, ethmoid region (dorsal view) B, ethmoTd region (inner view); C, ethmoid region (side view) j D, vomer and portion of parasphenoid (ventral view); F, nasal (dorsal view) 229 7. Cyprlnodon v. variegatus , orbitotemporal region: A, frontal and postorbital (dorsal view): B, frontal and postorbital (ventral view); C, lachrymal; D, alisphenoid ..... 250 8. Cyprinodon v. variegatus , parasphenoid, prootic, and vomer: A7 inner view; B, ventral view 251 9. Cyprinodon v. variegatus , otic region: A, pterolliic; B, epiotic; C, sphenotic; D, otoliths 252 10. Cyprinodon v. variegatus , exoccipital and basioccipitalj A, ventral view; B, inner view 255 11. Cyprinodon v. variegatus : A, exoccipital and basi- occipitaT (posterior view); B, supraoccipital (dorsal view) , . 254 12. Cyprinodon v. variegatus : hyomandibular, symplectic. mandibular arch, and opercular bones (outer view) . 254 ix j X LIST OF FIGURES—Continued Figures Page 15. Cyprinodon v. variegatus : hyomandibular, symplectic. mandibular arch and opercular bones (mesial view; . 235 14. Cyprinodon v. variegatus : hyoid cornu, branchiostegals and urohyal 235 15. A, branchial arches of Cyprinodon v. variegatus ; B, pharyngobranchial of Floridlchthys c. carpio . 256 16. Cyprinodon v. variegatus , pharyngobranchialsi A, inner""viewj B, ventral view 257 17. Cyprinodon v. variegatus t A, precaudal vertebraej B, caudal vertebrae) C, caudal vertebrae and caudal fin 257 18. Cyprinodon v. variegatus , first vertebra! A, anterior viewj B, posterior view 258 19. Cyprinodon v. variegatus : dorsal fin 258 20. Cyprinodon v. variegatus : anal fin 259 21. Cyprinodon v. variegatus : pelvic bones and fin rays . , 259 22. Cyprinodon v. variegatus : A, posttemporal and supra- cleithrum; B, pectoral girdle and fin rays 240 25. Pectoral girdle and fin rays of four species of cyprinodont fishes: A, Jordanella floridaej B, Qarmanella pulchra ; C, Floridlchthys c. carpio j D, Cualac tessellatus ~ 241 24. Aphanius