A new mid-Cretaceous hermit crab (Crustacea, Anomura) from Central Russia sheds new light on paguroid evolution

Abstract

Paguroid anomurans constitute a large portion of modern-day decapod crustacean assemblages in all oceans and seas across the globe. However, their palaeontological record is still rather patchy, which partly explains why their phylogeny remains poorly understood. A newly collected specimen of an extinct paguroid is here shown to have a major impact on the evolutionary history of this group of anomurans. A new genus and species, Mutotylaspis tripudium, are here erected to accommodate a well-preserved, extraordinarily crab-like hermit crab from the lower Albian (mid-Cretaceous) of Vladimir Oblast (Central Russia) that appears closely related to the extant enigmatic deep-sea taxon Tylaspis anomala Henderson, 1885, as well as to other members of the extant family Probeebeidae Boone, 1926. Ongoing palaeontological research during the last two decades has provided ample evidence that paguroid evolution was much more intricate and complex than gleaned solely from extant hermit crabs. The newly collected specimen named herein is the first fossil member of the family Probeebeidae and constitutes an additional key species for unravelling paguroid evolution and extending the stratigraphical range of the family downwards into the mid-Cretaceous.