Revision of the genus Protaxius (Decapoda, Axiidea, Axiidae), with description of a new species from the Lower Cretaceous of west-central Argentina

Abstract

A new species of Protaxius Beurlen, P. paucisaetosus sp. nov., is erected on the basis of 40 specimens from a single stratigraphic level within the Agrio Formation (lower Hauterivian) in the Neuquén Basin. Specimen preservation varies from isolated chelae to complete exoskeletons, all invariably enclosed in concretions. Since the genus Protaxius had previously been interpreted as a junior subjective synonym of Etallonia Oppel, we have revised the type material of all the species assigned to Protaxius so as to assess this proposal; we here reject this and consider Protaxius to be distinct. Previous records of species of Protaxius are from the Upper Jurassic of Europe and Japan, making the present record not only the first from the Southern Hemisphere, but also the first report of the genus from the Cretaceous, extending its stratigraphical range.