The earliest record of a diogenid hermit crab from the Late Jurassic of the southern Polish Uplands, with notes on paguroid carapace terminology.

A new species of diogenid paguroid, Eopaguropsis nidiaquilae, the earliest known member of the family to date, is recorded from sponge-reefal strata of Oxfordian (Late Jurassic) age in the southern Polish Uplands. Morphological features of the carapace suggest that the family Diogenidae diverged from other paguroid lineages such as the Pylochelidae and Parapaguridae, long before the Oxfordian Stage (161.2-155.7 Ma). The typically deep, V-shaped cervical groove of diogenids most likely was the product of fusion of the branchiocardiac and cervical grooves of their predecessors. [ABSTRACT FROM AUTHOR]