A first recognition of the orithyiid crab (Decapoda: Brachyura) from the Miocene Mizunami Group, Japan

Abstract

Orithyia eikii, new species discovered from the Lower Miocene Mizunami Group of Japan, constitutes the first reported occurrence of Orithyiidae Dana, 1852 in 1852–1853 in the fossil record. The new species superficially resembles Orithyia sinica (Linnaeus, 1771), the sole included extant species of the family and genus from East Asia, but it differs in having only one spine on the posterolateral margin of the carapace. The discovery of this species extends the geologic range for the family and genus back to the Early Miocene.