Bison occidentalis and associated invertebrates from the late Wisconsin of Randall County, Texas
1970; Cambridge University Press; Volume: 44; Issue: 5 Linguagem: Inglês
ISSN
1937-2337
AutoresGerald E. Schultz, Elmer P. Cheatum,
Tópico(s)Aquatic Invertebrate Ecology and Behavior
ResumoBison occidentalis is known from various Pleistocene sites in North America. The recent discovery of a skull of this species in Randall County, Texas, is worthy of note. The skull, which lacks the dentition and palatal region, was collected from a blue-gray to black organic clay deposit in a stream bank in the upper reaches of Palo Duro Canyon. The horn cores are complete; the spread is 775 mm. Associated with the skull were remains of small fish, ostracodes, two species of pelecypods, and twenty-three species of freshwater and land gastropods which together constitute the McCormick local fauna. Radiocarbon dating of the mollusks gave an age of 10,800 - 835 years B.P. From a quantitative analysis of the gastropods, it is quite obvious that the area was marshy with considerable standing water and had a climate much cooler with greater rainfall than that which prevails today. This conclusion is attested by the presence of large numbers of shells of the amphibious snails, Gyraulus parvus, G. circumstriatus, Stagnicola bulimoides techella, and Fossaria dalli. Among the twenty-three species of gastropods collected, Stagnicola. exilis, Promenetus exacuous, Gyraulus circumstriatus, and Vallonia gracilicosta have today a more northerly distribution. The presence of Vertigo ovata among the land species is indicative of unusually moist conditions associated with deep woodlands along water courses. The remain- ing land species present in the fauna may occupy habitats ranging from moist, deep wood- lands to sparse, well-drained woodlands.
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