THE OLDEST HIGHER TRUE CRABS (CRUSTACEA: DECAPODA: BRACHYURA): INSIGHTS FROM THE EARLY CRETACEOUS OF THE AMERICAS

摘要

Despite the extensive fossil record of higher crabs (Eubrachyura) from Late Cretaceous and Cenozoic rocks worldwide, their Early Cretaceous occurrences are scarce and fragmentary, obscuring our understanding of their early evolution. Until now, representatives of only two families of eubrachyuran-like crabs were known from the Early Cretaceous: Componocancridae and Tepexicarcinidae fam. nov., both monospecific lineages from the Albian (110-100Ma) of North and Central America, respectively. The discovery of Telamonocarcinus antiquus sp. nov. (Telamonocarcinidae) from the early Albian of Colombia, South America (110Ma), increases to three the number of known Early Cretaceous eubrachyuran-like families. The ages and geographical distributions of the oldest eubrachyuran-like taxa (i.e. Componocancridae, Telamonocarcinidae and Tepexicarcinidae fam. nov.) suggest that the oldest higher true crabs might have originated in the Americas; that they were already morphologically diverse by the late Early Cretaceous; and that their most recent common ancestor must be rooted in the Early Cretaceous, or even the Late Jurassic.