FOSSIL FISHES OF DEATH VALLEY NATIONAL PARK, CALIFORNIA: RECONSTRUCTING THE ORIGINS AND GEOGRAPHICAL DISTRIBUTION OF THE INDIGENOUS ICHTHYOFAUNA OF SOUTHEASTERN CALIFORNIA

Miller (1945) described three species of cyprinodont fossil fishes from Death Valley National Park (DVNP), southeastern California. Included was the only known record of the extinct pupfish Cyprinodon breviradius. The exact location and stratigraphic horizon of the respective fossil locality and, thus, the geologic age of the specimen have always been uncertain. Recent discoveries of fossil fishes most likely from the same locality represent a taxonomically diverse ichthyofauna. Pending verification, it comprises additional specimens of Cyprinodon (pupfish) and other cyprinodont genera and families, including the genera Profundulus (Middle American killifishes) and Fundulus (topminnows); the family Goodeidae including both subfamilies Empetrichthyinae (spring and poolfishes) and Goodeinae (splitfins); a perch-like fish of the Percidae family, possibly of the genus Etheostoma (darters) and from the Cyprinidae family a specimen resembling a dace. Continued collecting and analysis will likely increase the length of the taxonomic list. Fish are preserved in calcareous mudstones associated with spring mounds, algal mats, and include freshwater mollusks resembling Pyrgulopsis (springsnails). The exact age of the fossil-fish bearing mudstones is still unknown however they are stratigraphically above the Titus Canyon Formation (late Eocene to early Oligocene) and in an interval containing at least five intercalated ash-fall tuff beds. The tuff beds most likely fall within the range for Miocene tuff beds elsewhere in DVNP (ca. 18-10Ma). The extent of the fossil-bearing deposits (several square miles) and the diversity of the fauna will be critical in reconstructing the origins of the native fish fauna of DVNP and the subsequent geographical distribution of some of its constituents.