Fossil spiders (Araneae) from the Eocene Green River formation of Colorado

Abstract

Ten specimens of spiders from the Eocene (c. 49-50 Ma) Parachute Creek Member of the Green River Formation from Colorado are reported. None is sufficiently well preserved to be described as a new taxon. Spiders belonging to the Uloboridae (including Miagrammopes), Hersiliidae (Hersiliola), Selenopidae, and Thomisidae are described and illustrated. These extend the fossil record of Hersiliola, Mia-grammopes and Thomisidae. The Parachute Creek Member is a cyclical sequence of oil shales and evapor-ites which represents intermittent playa lake sediments. The arachnofauna of varied modes of life, possibly from a variety of habitats, was most likely preserved during flash flood episodes.