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NoqvitatesAMERICANt MUSEUM PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2796, pp. 1-86, figs. 1-39, tables 1-4 November 13, 1984 Jurassic Fishes from the Western United States, With Comments on Jurassic Fish Distribution BOBB SCHAEFFER' AND COLIN PATTERSON2 CONTENTS Abstract ..................................... 2 Introduction ..................................... 2 Methods and Materials .................................... 3 Acknowledgments ..................................... 3 Abbreviations ..................................... 4 Geologic Occurrence .................................... 5 Systematics .................................... 13 Chondrichthyes ..................................... 13 Elasmobranchii .................................... 13 Hybodontidae .................................... 13 Hybodus sp..................................... 13 Holocephali .................................... 14 Chimaeridae .................................... 14 Ischyodus sp. .................................... 14 Osteichthyes .................................... 14 Actinopterygii .................................... 14 Neopterygii .................................... 14 Halecostomi Incertae Sedis .................................... 14 Hulettia, New Genus ............... ..................... 14 Hulettia americana (Eastman) .................................... 14 Halecostomi .................................... 37 Semionotidae .................................... 37 Lepidotes sp. .................................... 37 Halecomorphi .................................... 38 Caturidae ..................................... 38 Caturus dartoni (Eastman) .................................... 38 'Curator Emeritus, Department of Vertebrate Paleontology, American Museum of Natural History. 2 Research Associate, Department ofIchthyology, American Museum ofNatural History; Senior Principal Scientific Officer, Department of Palaeontology, British Museum (Natural History). Copyright © American Museum of Natural History 1984 ISSN 0003-0082 / Price $7.39 2 AMERICAN MUSEUM NOVITATES NO. 2796 Teleostei .......................................... 40 Ichthyodectiformes Incertae Sedis ..................................... 40 Occithrissops, New Genus ....................................... 40 Occithrissops willsoni, New Species ................ ................ 40 Teleostei Incertae Sedis ................ ....................... 51 Todiltia, New Genus .......................................... 51 Todiltia schoewei (Dunkle) ....................................... 51 Discussion and Summary ......................................... 63 Appendix: The Distribution of Jurassic Fishes ...................................... 66 Literature Cited .......................................... 80 ABSTRACT Seven genera of fishes from the Jurassic (upper thyodectiform teleost, but not assignable to sub- Bathonian-Callovian) Sundance and Wanakah order. Todiltia schoewei (Dunkle), new genus from formations ofwestern United States are described the Wanakah, is a teleost compared with Ascala- and their relationships discussed together with a bos and Leptolepis, but its affinities remain un- review of their stratigraphic occurrence. The as- known. semblage includes isolated teeth ofthe chondrich- The problem of incertae sedis genera and species thyans Hybodus sp. and Ischyodus sp., in part from (e.g., the monotypic Hulettia) is discussed in re- unrecorded Sundance localities near Hulett, Wy- gard to identification and relationships ofJurassic oming. Most common is the generalized neopte- fishes from other parts of the world. Included ta- rygian Hulettia americana (Eastman), new genus bles and paleogeographic maps show temporal and of unknown relationship, which occurs in the spatial distribution of these fishes, but variable Sundance of Montana and Wyoming, and in the preservation, inadequate description, and super- Wanakah ofColorado (including the Pony Express ficial systematic analysis usually preclude detailed Limestone) and New Mexico (Todilto Limestone). comparisons of Jurassic taxa from the literature. Lepidotes sp. and Caturus dartoni (Eastman), which It is probable, however, that most Jurassic fish belong to a monophyletic species group within the assemblages, like those ofthe Sundance-Wanakah, genus Caturus, are both present in the Sundance are mixtures ofform genera and monotypic genera and the Wanakah. Occithrissops willsoni, new ge- whose relationships are imprecisely known. nus, new species from the Sundance, is an ich- INTRODUCTION Our knowledge ofdiversity among various has yielded a fish assemblage that approaches groups of fishes that existed during the Ju- the diversity of the European ones (Gregory, rassic is mostly derived from a few major 1923; D. H. Dunkle, personal commun.). collecting areas in England, France, and Ger- Unfortunately, this fauna is mostly unstud- many. Specimens obtained from these local- ied. More recently Arratia (1982), and others ities have been studied longer and more in- have reported on Oxfordian fishes from tensively than those from rocks ofsimilar age northern Chile. In regard to North America, in other parts of the world. But in order to fishes have long been known from the Sun- obtain a broader understanding of both the dance Formation in South Dakota (Eastman, elasmobranch and osteichthyan fishes during 1899b) and from the Todilto Limestone in this significant interval in their history, it is New Mexico (Koerner, 1930). The primary obviously desirable to search for localities purpose of the present paper is to describe outside of Europe. The European taxa will, and consider the relationships of the fishes of course, continue to play a major role in from the Sundance Formation in northeast- working out the subtleties ofrelationship and ern Wyoming and from the Wanakah For- diversification, but well-preserved specimens mation (including the Todilto), and equiva- from elsewhere should provide additional in- lent units, in northern New Mexico and sights into phylogeny and paleobiogeogra- Colorado. With assistance from members of phy. the United States Geological Survey, an effort For the Western Hemisphere, only the Late has also been made to clarify the age and Oxfordian Jagus Formation in western Cuba somewhat enigmatic stratigraphic relation- 1984 SCHAEFFER AND PATTERSON: JURASSIC FISHES 3 ships ofthe rock units containing these fishes. Mr. R. J. Greffenius of the U.S. Forest Ser- A second objective is to summarize the avail- vice provided information about the fish lo- able information on marine and non-marine cality in the Pony Express Limestone in Pie- Jurassic fish assemblages from various parts dra River Canyon, Colorado, and Dr. G. D. of the world in relation to their distribution, Johnson for the locality near Hot Springs, composition and to current problems ofiden- South Dakota. tification and relationship. The regional geology and stratigraphic re- lationships of the Sundance Formation and METHODS AND MATERIALS the Todilto Limestone and Pony Express Limestone members of the Wanakah For- We have not been successful in making to- from the mation have been clarified through the gen- tal acid preparations of specimens erous assistance of Drs. George Pipiringos American Jurassic localities mentioned in this (retired) and Robert B. O'Sullivan ofthe U.S. report. However, many morphological de- Geological Survey. Additional information tails have been enhanced by local application has been supplied by Drs. Jennie L. Ridgley offormic or acetic acid, by Smooth-On® peels and J. Platt Bradbury, also ofthe Survey, and obtained from natural or prepared negative by Dr. W. F. Tanner. Drs. Ralph Imlay, An- specimens and by the use of alizarin to dis- H. Callomon, Hans-Pe- the good to thony Hallam, John tinguish bone from matrix. Also, ter Schultze, and John Utgaard provided excellent preservation of various neopteryg- opinions on problems ofcorrelation and dat- ian specimens has permitted interpretation ing. Drs. David H. Dunkle and Joseph T. of the dermal skull, some deeper skull struc- Gregory supplied data regarding the Todilto tures, and certain aspects of the postcranial Limestone at the Bull Canyon Todilto fish skeleton. The catalogued specimens listed for locality in northeastern New Mexico. The each taxon have been selected for their in- writers are greatly indebted to all of these formation content, and are the ones on which colleagues for their assistance and coopera- the descriptions are based. tion. For valuable discussion about systematic ACKNOWLEDGMENTS problems we are obligated to Drs. Peter L. The research for this paper was facilitated Forey, Brian G. Gardiner, Lance Grande, by a grant from the National Geographic So- Philippe Janvier, John G. Maisey, Amy R. ciety to Dr. Schaeffer, and by financial sup- McCune, Paul Olsen, and Donn E. Rosen. port to Dr. Patterson from the Department Mr. Walter Sorensen accompanied Schaef- of Geology, Field Museum of Natural His- fer during the first few collecting trips in Wy- tory, during his tenure there as Visiting Sci- oming and New Mexico, and he has prepared entist. The American Museum of Natural most ofthe specimens. Mr. Gilbert F. Stucker History has provided resources for many of served in this capacity during the remainder the illustrations. of the field program. Additional field assis- The fieldwork involved in obtaining the tance was provided at various times by Ms. fish specimens from the Sundance