Late Pleistocene Freshwater Fishes from the Rancho La Brea Deposit, Southern California
Swift, Camm C.
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Three species of Pleistocene freshwater fishes occur at Rancho La Brea, <br /><br />the type deposit of the Rancho La Brea Age MammaHan faunas. Remains of <br /><br />rainbow trout, Salmo gairdneri, (mostly isolated vertebrae) and threespine stick- <br /><br />leback, Gasterosteus aculeatus (primarily pelvic spines), are both common. One <br /><br />dentary and two vertebrae represent one individual of arroyo chub, Gila orcutti. <br /><br />Based on pelvic and dorsal spine morphology, a relatively unarmored form of <br /><br />stickleback (possibly representing the recent Gasterosteus aculeatus williamsoni) <br /><br />existed in the Los Angeles Basin up to 30,000 years ago. Collectively the fish <br /><br />fossils indicate local, permanent stream conditions, and not stream transport from <br /><br />distant mountainous areas 10-30 km away. Absence of the more montane Ca- <br /><br />tostomus santaanae and Rhinichthys osculus also argues against long-distance <br /><br />transport. As with other ectothermic organisms (and possibly small endotherms), <br /><br />no extinct freshwater fishes are known from the Rancho La Brea deposits.