New record of a rare copepod, Metridia bicornuta Davis, 1949 (Calanoida, Metridinidae) for the South China Sea

Abstract

Abstract The genus Metridia Boeck, 1864 is widely distributed in the global ocean, but only 9 species of Metridia have been recorded from the China seas. Here we report the rare copepod Metridia bicornuta Davis, 1949 for the first time for the South China Sea. One specimen was collected from the southern basin of the South China Sea (13°0.21′N 113°0.21′E) at depths of 500-800 m. Females of this species differ from those of congeneric species by the following features: (i) Prosome 1.5 times as long as urosome; (ii) forehead with lateral points projecting on both sides; (iii) genital somite 1.8 times as long as the second somite; (iv) distal segment of fifth swimming leg (P5) with a small outer marginal spine and 3 subequal robust terminal setae. This finding expands the known global distribution of M. bicornuta, and increases the number of copepod species in the China seas.