Unusual Albian (early cretaceous) Brachyura (Homoloidea: Componocancroidea new superfamily) from Montana and Wyoming, U.S.

摘要

Brachyuran specimens collected from the Albian (Early Cretaceous) age Shell Creek Shale in Montana and Wyoming provide the basis for description of two new species, Zygastrocarcinus waagei and Componocancer roberti. The former represents only the fourth species of a genus that is endemic to the Cretaceous of mid-continental North America. The latter species is assigned to a new superfamily, Componocancroidea; new family, Componocancridae; and new genus, Componocancer, within Heterotremata. Componocancer exhibits a combination of primitive and derived features that is unique among Brachyura.