Two new Scolelepis species (Annelida: Spionidae) from the Yellow Sea in Korea.

Abstract

Two new spionid polychaetes of the genus Scolelepis from the intertidal habitats of the Yellow Sea in Korea are described and illustrated. Scolelepis (Parascolelepis) anterobranchiata sp. nov. is characterized by a combination of the following characteristic: palps with smooth globular expansions at the basal part, branchiae appearing in the anterior part of the body, absence of notochaetae in chaetiger 1, notopodial postchaetal lamellae partially fused with branchiae in anterior chaetigers, and neuropodial hooded hooks appearing from chaetigers 1819 with two pairs of teeth surmounting a well-developed main fang. Scolelepis (Scolelepis) rubra sp. nov. can be distinguished from its congeners by the following characteristics: reddish-pink body, presence of notochaetae in chaetiger 1, branchiae approximately twice as long as notopodial postchaetal lamellae, neuropodial bidentate hooded hooks usually appearing from chaetigers 2631, and presence of notopodial hooded hooks in posterior chaetigers. Based on molecular data, the sequences of the two new species showed relatively large genetic distances from other Scolelepis species in COI (15.819.5%) and 16S rDNA (4.915.8%). Morphological variability of prostomial shape in the genus Scolelepis is discussed for the first time.