The distribution of Tantilla utahensis Blanchard

Abstract

Tantilla utahensis was originally described by Blanchard (1938: 372-3), based on a few specimens from southwestern Utah and east central California. Since then there has been uncertainty as to its distributional limits. The occurrence of known populations in Utah and California with no authentic records from Nevada left a hiatus in the distribution which seemed artificial. Recent field work in the Nevada Atomic Test Site as well as in California and Utah has not only extended the range of T. utahensis in California and Utah, but has also provided specimens from southern Nevada, thus bridging the widely separated populations in Utah and California. The first record of this species was published by Van Denburgh (1922:880), who listed it as Tantilla nigriceps, based upon a specimen in the collection of the California Academy of Sciences taken by V. M. Tanner at Saint George, Washington County, Utah. This specimen became the holotype for T. utahensis (Blanchard, loc. cit.; Slevin and Leviton, 1956:549). V. M. Tanner (1927:57) and Woodbury (1928:21 and 1931:107-8) listed a Tantilla for southwestern Utah, but also referred it to Tantilla nigriceps. More recently Tanner (1954:92-4) extended the range in Utah (to central Kane County) and reported a record for nothern Arizona. Since this report T. utahensis has been found at Star Spring, on the southeast slope of Mount Hilliar (elevation 6,000 feet), Garfield County, Utah. This record extends the range approximately 1 00 miles to the northeast.