New records of three species of Spinoncaea Böttger-Schnack, 2003 (Copepoda, Cyclopoida, Oncaeidae) in the North Pacific Ocean

Abstract

Three species of the genus Spinoncaea is redescribed based on specimens collected using a fine-mesh net (60 ㎝ mouth diameter, 60 ㎛ mesh size) in the Korea Strait, and the northwestern and the northeastern Pacific Ocean. The Pacific specimens of Spinoncaea species mostly coincide with the characteristic features as described for S. tenuis Böttger-Schnack, 2003, and S. humesi Böttger-Schnack, 2003, in the original account. However, Spinoncaea ivlevi (Shmeleva, 1966) shows additional ornamentations to that reported in the Red Sea, in terms of the ornamentation on the intercoxal sclerite of the first leg in both sexes, and the ventral ornamentation on the genital segment in the male. Spinoncaea species have a wide geographical distribution since it had recently been reported in various regions (e.g. the Red sea, the Mediterranean Sea, the Adriatic Sea, the Indian Ocean, the Pacific Ocean). It adds the equatorial Pacific to the distribution of three Spinoncaea species, and first report them in Korea’s surrounding waters.