Late Pleistocene Vertebrates from a Mormon Mountain Cave in Southern Nevada
Jefferson, George T.
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Late Pleistocene Vertebrates from a Morman Mountain Cave in Southern Nevada by George T. Jefferson, Bull. Southern California Acad. Sci., 81(3): 121-127, 1982. A mammalian assemblage of latest Pleistocene Early Recent age containing animals no longer living in southern Nevada has been recovered from a limestone cave on the north side of the Mormon Mountains, Lincoln County, Nevada, approximately 1 12 kilometers northeast of Las Vegas. The cave is developed in late Paleozoic limestones and lies at an elevation of approximately 1372 meters above sea level in an area which supports a pinyon-juniper, sagebrush floristic community. Some of the fossil species from the cave have modem representatives that presently live in this habitat. Other species, such as Ochotona princeps (pika), Marmota flaviventris (marmot), and Citellus lateralis (golden mantled ground squirrel) either do not now range into southern Nevada or are present only at the highest elevations in this region, in pine or fir forest at elevations about 2135 meters. The fossil occurrence of Ochotona, Marmota, and Citellus lateralis in southern Nevada is anomalous relative to their present distribution and suggests that pine and fir floras were at least 610 to 915 meters lower in elevation when these taxa were living in the area. Upward shifts of floristic communities in the Southwest have been attributed to the warming trend of post-Wisconsin climates over the past 8000 to 11 ,000 years. Changes in the distribution of small mammals in the Southwest have occurred in response to geographic shifts of floristic communities. <br />The difference in elevation between the cave assemblage and Recent small mammal faunas of similar composition is compared to the difference in elevation between radiocarbon-dated fossil floras and Recent floras. These correlations provide an approximate minimum age of 8000 years before present for the assemblage.