A new alligator lizard from the Panamint Mountains, Inyo County, California. American Museum novitates ; no. 1883

Abstract

In the higher mountains of southwestern United States, as in arid regions elsewhere in the world, are isolated species of plants and ani- mals that are unable to exist in the surrounding dry lowlands.They or their ancestors must have dispersed across the intermountain basins at a time when conditions of temperature and humidity were more favorable to them than now.The divergence of many of the isolated organisms from their closest relatives in other areas indicates an evolu- tionary history antedating man.AMERICAN MUSEUM NOVITATES NO. 1883 dence Mountains,' San Bernardino County, California, between the main body of the species and D. regalis of Arizona, Tantilla utahensis in the Panamint and Charleston Mountains, between Tantilla eiseni of California and T. atriceps of Arizona, and Eumeces gilberti in the Panamints, between the main body of the species in California and an isolated population on the Arizona plateau.Once more the Panamint Range is found to afford sanctuary for a reptile that is intolerant of desert conditions.On October 23, 1954, James McDonald, Jr., found an alligator lizard (Gerrhonotus) in Surprise Canyon at an elevation of 4500 feet.Subsequent collecting provided additional specimens, and the present study shows this lizard to be related to Gerrhonotnts multicarinatuts (including its close relatives paucicarinatus and cedrosensis) and G. kingi, yet sufficiently dif- ferent to be regarded as a new species.We may add, therefore, another example of a reptilian desert isolate suggestive of a former connection between mesic elements in the herpetofauna of Arizona an(d those of California.