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Cruz, J. Alberto

La Brea Tar Pits and Museum

5801 Wilshire Blvd

Los Angeles, California USA.

Centro de Investigación Paleontológica Quinametzin

Coordinación Nacional de Arqueología

Instituto Nacional de Antropología e Historia


Lindsey, Emily L.

La Brea Tar Pits and Museum

5801 Wilshire Blvd

Los Angeles, California USA

Lizards exhibit high taxonomic and morphological diversity and occupy a wide range of ecological roles in ecosystems. Many lizard species have been subject to serious extinction risk induced by climate change. One North American locality that does preserve a robust fossil record of lizards is Rancho La Brea (RLB) in Los Angeles, California, owing to naturally occurring seeps of asphalt that have trapped and preserved hundreds of species over the past 60,000 years. Paleontological studies of lizards at Rancho La Brea (RLB) started in the 1950s, and since then only three studies have been conducted, identifying 8 taxa including the alligator lizard (Elgaria multicarinata), legless lizard (Anniella sp.), horned lizard (Phrynosoma coronatum), spiny lizards (Sceloporus magister, S. occidentalis), side-blotched lizards (Uta stansburiana), skink (Plestiodon skiltonianus), and whiptail (Aspidoscelis tigris) from the Pleistocene of RLB. All of these species are present today in the RLB area except S. magister. In this study, we analyzed the RLB fossil collection from the La Brea Tar Pits and Museum (LBTPM) and the University of California Museum of Paleontology (UCPM) to develop a complete lizard taxonomic list for this site. We compared the fossil material with recent skeletal from the Herpetological Collection of Natural History Museum, Los Angeles County (LACM), the Museum of Vertebrate Zoology (MVZ), and UCPM. We identified the horned lizard as P. blainvillii and we added the tree lizard (Urosaurus sp.) and the arboreal alligator lizard (Abronia) for the diversity in RLB. S. magister, Urosaurus, and Abronia are not currently present in the RLB area, indicating distribution changes during the Pleistocene, possibly due to vegetation and/or climate change. More morphological studies are necessary to be able to separate between different species of fossil lizards. Together, this information allows us to understand the Quaternary climate change of southern California.


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