Designation of Ancylomenes gen. nov., for the ‘Periclimenes aesopius species group’ (Crustacea: Decapoda: Palaemonidae), with the description of a new species and a checklist of congeneric species

A new genus of the subfamily Pontoniinae, Ancylomenes gen. nov. is established for the ‘Periclimenes aesopius species group’ of the genus Periclimenes Costa. The new genus is distinguished from other genera of Pontoniinae on account of the strongly produced inferior orbital margin with reflected inner flange, and the basicerite of the antenna armed with an angular dorsal process. Fourteen species have been previously recognized as belonging to the ‘P. aesopius species group’. One Eastern Pacific species (P. lucasi Chace), and two Atlantic species (P. anthophilus Holthuis & EiblEibesfeldt, and P. pedersoni Chace) are now also placed in Ancylomenes gen. nov. A further new species associated with a cerianthid sea anemone, A. luteomaculatus sp. nov. is described and illustrated on the basis of specimens from the Ryukyu Islands, southern Japan, and Philippines. A key for their identification, and a checklist of the species of Ancylomenes gen. nov. are provided.