FOSSIL CHELONIANS, CHRYSEMYS AND CLEMMYS, FROM THE UPPER PLIOCENE OF IDAHO G. R. Zugi The extant reptilian fauna of the Columbian Plateau and the northern half of the Basin and Range Province lacks turtles. Their absence appears to be of relatively recent occurrence, for turtles per-sist in the surrounding areas and have been found in Plio-Pleistocene deposits, Glenn Ferry Formation, of this region. The latest faunal list for the Glenn Ferry Formation (Taylor. 1966. p. 75) includes Kinosternon sp. and Pseudemy idahoensis. Through the effort of Dr. C. W. Hibbard and his field parties, a large collection of chelo-nian shell fragments has been amassed from the vicinity of Hager-man, Twin Falls County, Idaho. Unless indicated otherwise, the specimens reported herein are from the Hagerman area. Family Kinosternidae Kinosternon Spix Remarks. There are no elements that can be assigned to this taxon. Unfortunately, it seems that Taylor (1966) misread Hibbard's (1959), p. 11) statement. Hibbard indicated only that the shell fragments may represent "Kinosternon, Chrysemys, or Pseudemy sJ' This error was compounded by the limited distribution of a faunal compilation and as such has appeared elsewhere (Holman, 1968). Family Testudinidae Chrysemys idahoensis (Gilmore) Material. Peripherals, UMMP V45276A, V52778; Hyoplas-tron, UMMP V53417; Xiphiplastra, UMMP V53417, V54129. Remarks. Of the two turtles represented in this collection, very few elements can be assigned to C. idahoensis. All Chrysemys ele-ments were compared with Gilmore's type series and match the morphology therein. A humeropectoral sulcus extends across the entire width of the hyoplastron and distally forms an anterior loop (Gilmore, 1933, PI. 2). Both xiphiplastra possess a strong step later-ally between the femoral and anal scutes and a shallow dorsal groove medial of the scutes. These features are characteristic of C. idaho-ensis. An anterior half of a plastron (UMMP V42609) has been recov-ered from the Late Hemphilian Wolf Canyon area of Meade County. Kansas. The humeropectoral sulcus of this plastron forms an an-terior loop laterally on each side, indicating that this fossil is also C. idahoensis. Thus temporally, C. idahoensis extends from approxi-^United States National Museum, Washington, DC. 82
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