New Eocene Hydrocarbon Seep Decapod Crustacean (Anomura: Galatheidae: Shinkaiinae) and its Paleobiology

A new decapod crustacean species, Shinkaia katapsyxis, is reported from the Eocene Humptulips Formation of western Washington, USA. The specimens were collected from a hydrocarbon seep deposit that has been well-documented and contains a well-described molluscan fauna. The new occurrence extends the geologic range of the genus Shinkaia Baba and Williams, 1998, and subfamily Shinkaiinae Baba and Williams, 1998, into the Eocene from its only other known occurrences in hydrothermal vent environments in the Pacific Ocean. The range extension of an extant decapod genus into the Eocene is not uncommon and adds to the evidence that the Decapoda may be unusually resistant to extinctions and are distinctly conservative evolutionarily.