A new genus and species of shrimp (Crustacea: Axiidea: Axiidae) from the Caroline Ridge, northwest Pacific

Abstract

A new genus and species of axiid shrimp, Carolinaxius kexuae gen. et sp. nov. is described and illustrated based on a single specimen collected from an unnamed seamount in the Caroline Ridge, northwest Pacific. Although both chelipeds are missing, the specimen can be distinguished from other axiid genera by a combination of characteristics: narrowly triangular rostrum; median carina and lateral gastric carina each with one prominent tooth; submedian gastric carinae converging posteriorly, with teeth; cornea weakly pigmented, eyestalk with acute distomesial tooth on dorsal surface; male pleopod 1 two-articled; pleopod 2 with appendix interna and appendix masculina; pleopods 3–5 with appendix interna. The molecular phylogeny suggests the new genus is most closely related to another recently described genus living inside hexactinellid sponges on seamounts in the Indian Ocean, Montanaxius Dworschak, 2016. However, it differs from Montanaxius in the shape of the rostrum, the arrangement of teeth on the carapace, and the shape of the eyestalk. Besides, the significant molecular differences support the two belonging to different genera.