Hyperbionyx athesphatos n.sp. (Calanoida: Hyperbionychidae), a rare deep-sea form taken from the tropical North Atlantic

A second species of Hyperbionyx (H. athesphatos n. sp.) from the calanoid copepod family Hyperbionychidae Ohtsuka et al., 1993 is described from near the sea floor of the Cape Verde Abyssal Plain in the tropical water of south-eastern North Atlantic based on the male. This species may be distinguished from the only other species in the genus and family (H. pluto) by the large, complicated, recurved extension of exopod segment 2 of the male left fifth leg, which is opposed to exopod segment 3, and the presence of a leaf-shaped endopod on the same leg.