Description of a new species of Neoargestes Drzycimski, 1967 (Copepoda, Harpacticoida, Argestidae) from the Clarion Clipperton Fracture Zone (Pacific Ocean), with remarks on the systematics of the genus

Abstract

Neoargestes laevis sp. nov. (Copepoda, Harpacticoida, Argestidae), the third species of the genus, is described from the Clarion Clipperton Fracture Zone (Pacific Ocean), and a re-description of the holotype of Neoargestes incertus Becker, 1979 is provided. The generic diagnosis of Neoargestes Drzycimski, 1967 is amended and its allocation to Argestidae is confirmed. The monophyly of Neoargestes is recognized by six autapomorphies: transformation of the mandibular gnathobase into a strong masticating apparatus with a broad front, reduction in size of the first endopodal segment in P2–P4, and reduction in size of the P5 baseoendopod and exopod. The presence of 3-segmented endopods in P2–P4 in Neoargestes points to a rather basal position of the genus within Argestidae. Its affinities to Argestinae, Bodinia George, 2004 and Odiliacletodes Soyer, 1964 as well as its intrageneric systematics are briefly discussed.