New record of mollusks from the El Molino mammoth site, Parras, Coahuila, Mexico

Abstract

We present new Late Pleistocene and Holocene records of a land and freshwater malacofauna assemblage from the mammoth bearing site El Molino in Parras, Coahuila, northern Mexico. We identified 19 mollusk taxa, 14 species were found within the Late Pleistocene sediments and 10 species in the different strata belonging to the Holocene. The gastropods Gastrocopta tappaniana, Pupilla hebes and Habroconus sp. are new Late Pleistocene records for Mexico, the first two being previously recorded for United States Pleistocene deposits. New Mexican Holocene fossil records include Euglesa casertana, Galba humilis, Gastrocopta cristata, Zonitoides arboreus, Hawaiia minuscula, and Deroceras laeve. The habitat requirements of the El Molino site malacofauna assemblage provides additional information on the environmental changes that occurred during the Pleistocene-Holocene transition. Woodland associated, hygrophilic and hydrophilic malacofauna suggest a humid forested and grassland habitat during the Late Pleistocene, which subsequently changed to xeric conditions with the colonization of xerophytic and aridity-tolerant aquatic species during and after the Pleistocene-Holocene transition at the study area.