Mesozoic and Cenozoic fossil isopods of North America

Abstract

Nine species of fossil isopods have been studied from Cretaceous to Pleistocene rocks of North America. This represents all known species from the Mesozoic and Cenozoic fossil record on this continent. Four species of Palaega were studied. Palaega goedertorum Wieder and Feldmann, 1989, from upper Eocene to lower Miocene rocks of Washington state, has served recently as the basis for restructuring the genus. Emendations are made to species descriptions of Palaega guadalupensis and P. williamsonensis from the Cretaceous rocks of Texas. The fourth species of Palaega, P. lamnae, also from the Cretaceous rocks of Texas, although of doubtful affinities with this genus, was not removed due to lack of sufficient information to reassign it. Two new species are described, Cirolana enigma, from Lower Cretaceous rocks of South Dakota, and Archaeoniscus texanus, from the Cretaceous of Texas. This is the first report of Cirolana from the fossil record. Two sphaeromatid isopods were included: one, Sphaeroma burkartii from Tertiary rocks of Mexico, was not located for study; the other, Eocopea oculata, is from Miocene rocks of southern California. Two specimens of the valviferan genus Saduria, from Pleistocene deposits in Canada, were also studied.