A LARGE SPECIMEN OF THE GENUS ERYMA (CRUSTACEA, DECOPODA) FROM THE LATEST CALLOVIAN OF NORTH AMERICA

A large specimen of the lobster Eryma was discovered in the Lower Redwater Shale member of the Sundance Formation of Natrona County, Wyoming. Decapods are rare elements in the Jurassic of North America. Previous workers have found sparse numbers of speciens in the Stockade Beaver Member of the lower Sundance. Recent fieldwork in the Sundance Formation has produced new material, and this specimen represents only the second report of an erymid from the Jurassic rocks in North America. The new specimen is the mold of an anterior portion of a carapace with a mid-portion of a propodus and scattered fragments portions. This new specimen is compared to the holotype specimen of Eryma foersteri. and its paleoenvironment is examined and compared to the contemporaneous paleoenvironment of the Oxford Clay. The paucity of decapods from the Upper Sundance Formation is examined in relation to conditions such as collection bias, preservation bias, faunal stasis, and potential predation.