Reappraisal of the burrowing lobster axius (Malacostraca, Decapoda, Axiidea) in the fossil record with notes on palaeobiogeography and description of a new species

The fossil record of the burrowing lobster Axius is reviewed. A diagnosis based on the characters with preservation potential is supplied. Plioaxius lineadactylus Fraaije et al., 2011, from the Pliocene of Belgium and the Netherlands is considered congeneric with the type species of Axius. As a consequence, Plioaxius is considered a junior subjective synonym of Axius. A newly described species, Axius hofstedtae from the late Oligocene of Denmark is considered the oldest unequivocal representative of Axius. Both fossil species, A. hofstedtae n. sp. and A. lineadactylus n. comb., share numerous morphological characters with extant Axius stirhynchus. Scarcity of the Cenozoic Axiidae is ascribed to lack of study of the fossil record of this group rather than to low fossilization potential of its representatives. A preliminary scenario of the migration of Axius based on the scarce fossil record suggests the origin in the Western Tethys and subsequent dispersal westward into the West Atlantic and eastward into the West Pacific.