A New Species of Monstrillopsis Sars, 1921 (Copepoda: Monstrilloida) with an Unusually Reduced Urosome

Abstract

Male monstrilloid copepods, described herein as Monstrillopsis paradoxa sp. nov., were collected from the Chuja Islands, Jeju, Korea, using a light trap. They display many of the common features of Monstrillopsis, including large, prominent eyes, an anteriorly positioned oral papilla, and four setae on each caudal ramus. Type-2 modification of the antennules further supports the assignment of the new species to Monstrillopsis. However, the present specimens have an unusually low number of urosomal somites, just three in total, compared to five in males of all congeneric species, and from four (in Cymbasoma) to five in males of all other monstrilloid genera. Up until now, in the Monstrilloida only females of Cymbasoma have been known to have as few as three urosomal somites.