Redescription of Remaneicaris ignotus (Dussart, 1983), a Parastenocarididae (Copepoda: Harpacticoida) with an unusual set of plesiomorphic characters

Abstract

In the course of a phylogenetical analysis of the family Parastenocarididae we re-describe here both sexes of Remaneicaris ignotus (Dussart, 1983) and its phylogenetic position within the genus Remaneicaris is briefly discussed. This species can be distinguished from the other species of the genus by the following autapomorphies: absence of an outer seta on the basis of the leg 1 in both sexes; presence of a very chitinized and perforated cuticle; presence of a less chitinized plate between the fifth leg, not homologous to the intercoxal plate and the presence of an irregular shaped leg 4 enp on males, hirsute on the proximal outer margin and with a distal hyaline seta. It can be easily identified as well by the presence of some unusual plesiomorphic characters, unknown so far from any other member of the genus. In this sense, we can mention the presence of a dorsal integumental window on all urosomites, an inner seta on the basis of leg 1 in males and females, the ventral position of leg 5 and the linear distribution of the proximal outer row of spinules on exopodite 1 of legs 2 and 4.