A diverse Rancholabrean vertebrate microfauna from southern California includes the first fossil record of ensatina (Ensatina eschscholtzii: Plethodontidae) Thomas A. Wake a, ⁎ , Mark A. Roeder b a Zooarchaeology Laboratory, The Cotsen Institute of Archaeology at UCLA, A-210 Fowler, 405 Hilgard Ave., University of California, Los Angeles, CA 90095-1510, USA b Department of Paleontology, San Diego Natural History Museum, P.O. Box 131290, San Diego, CA 92112, USA abstract article info Article history: Received 15 October 2008 Available online 19 August 2009 Keywords: Southern California Rancholabrean Pleistocene Paleoecology Microfauna Herpetology Riparian Zone Ensatina Batrachoseps Analysis of late Pleistocene fossils recovered from near the Huntington Beach, California (USA), pier (site LACM 7679) has revealed a diverse fauna dating to approximately 40 14 C ka BP. Extinct megafauna (three genera) are present; however, a microfauna including three genera of fish, five genera of amphibians, twelve genera of reptiles, two genera of birds, and ten genera of small mammals dominates the assemblage in terms of diversity. Additional identification of seven genera of non-marine mollusks and various macro- and microscopic plant remains including grasses, three families of herbs, and seven genera of trees provides a wealth of information concerning the past ecology of what is currently a coastal dune field complex. During the Rancholabrean Period, the LACM 7679 locality was approximately 10 km inland from the Pleistocene coastline and contained lush riparian zones interspersed with coastal sage scrub, a few trees, and grasslands teeming with a variety of small and large animals. © 2009 University of Washington. Published by Elsevier Inc. All rights reserved. We summarize results of analysis of fossil amphibian and reptile bones recovered from a recently excavated paleontological locality in southern California. Results of mammal, bird, fish, mollusk and pollen analysis are included as well. The Pacific City (LACM 7679) site is located approximately 1 km south of the Huntington Beach Pier and 1 km inland from the current shoreline (Fig. 1). The site lies in stabilized Pleistocene dune deposits consisting primarily of fine- grained fluvial sands with isolated deposits of silts and clays. These sediments are most likely associated with late Pleistocene channels of the Santa Ana River system (De Barros and Roeder, 2001). The microfauna in question was recovered from a thin, dark organic layer of fine-grained silts and clays within the broader light tan interbedded fluvial sand deposits. The Pacific City development site includes several localities dating to the late Pleistocene based on the presence of Columbian mammoth (Mammuthus columbi), horse (Equus sp.) and bison (Bison cf. anti- quus) bone specimens found spread across the upper layers of the property (De Barros and Roeder, 2001). Caliche associated with these megafaunal remains has been radiocarbon dated to 19,890±120 14 C yr BP (Beta-136197). A single freshwater mollusk shell recovered from the dark organic layer that produced the microfaunal remains discussed here (LACM 7679) has been AMS radiocarbon dated to 40,980 ± 800 14 C yr BP (Beta-224795), firmly placing the deposit in the Rancholabrean Period of the Pleistocene. The diverse microfauna recovered from LACM 7679 includes a variety of small mammals, birds, reptiles, amphibians and fish. Several late Rancholabrean herpetofaunas have been described from southern California. The most diverse and well-known collec- tions come from the La Brea tar pits in central Los Angeles and are housed in the Page Museum (e.g., Brattstrom, 1953; LaDuke, 1991a,b; Stock, 1992). Brattstrom (1955) reported a small Pleistocene herpe- tofauna from Carpinteria. All of the species identified at Carpinteria are represented at Rancho La Brea. Hudson and Brattstrom (1977) and Miller (1971) have reported two other Rancholabrean herpetofaunas from Orange County, again duplicated at Rancho La Brea. In contrast, we report here that the LACM 7679 collection includes amphibian species neither represented at Rancho La Brea nor anywhere else in the continental United States. The LACM 7679 herpetofauna is summarized in Table 1 . Methods A bulk sample of 1000 kg of fine-grained fossil-bearing sediments was collected in the field. These sediments were treated with a variety of defloculants and washed through 0.5-mm mesh. The resulting sands were sorted to remove any fossil remains. Thomas Wake identified the fish, amphibian, and reptile remains using comparative osteological specimens housed in the UCLA Institute of Archaeology Zooarchaeology Laboratory (UCLAZL) and specimens on loan from the U.C. Berkeley Museum of Vertebrate Zoology (MVZ) and The Los Angeles County Museum of Natural Quaternary Research 72 (2009) 364–370 ⁎ Corresponding author. Fax: +1 310 206 4723. E-mail address: twake@ucla.edu (T.A. Wake). 0033-5894/$ – see front matter © 2009 University of Washington. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.yqres.2009.06.012 Contents lists available at ScienceDirect Quaternary Research journal homepage: www.elsevier.com/locate/yqres