Terminal Pleistocene Fish Remains from Homestead Cave, Utah, and Implications for Fish Biogeography in the Bonneville Basin

Eleven fish species were identified from Homestead Cave, Utah. The remains, concentrated in the lowest stratum of the deposit, were accumulated by owls between approximately 11,200 and 10,100 14C yr B.P. and likely represent fish associated with the final die-off of the Lake Bonneville fauna. Four of the species (Salvelinus confluentus, Prosopium abyssicola, Catostomus discobolus, Richardsonius balteatus) represent their first records for Lake Bonneville. The S. confluentus premaxilla is the first Quaternary specimen record for the genus in the Great Basin and suggests a southern range extension during the Pleistocene. The C. discobolus specimens represent the first fossil records for the subgenus Pantosteus in the Great Basin; their presence in Lake Bonneville documents a Pleistocene connection between two presently disjunct populations. The hyomandibulars of Prosopium gemmifer are different from Recent specimens in a pattern suggesting Holocene introgression with Prosopium spilonotus. The lack of Cottus echinatus and the presence of both Cottus bairdi and Cottus extensus may suggest the former species evolved in Utah Lake over the last approximately 10,000 yr B.P. The abundance of Catostomus ardens and the absence of Chasmistes liorus may reflect a restricted spatial distribution of the latter in Lake Bonneville.