A new species of Nicolea (Annelida, Terebellidae) from Qingdao, China

Terebellidae is a large group of tubicolous annelids commonly found in benthic marine environments worldwide, from shallow to deep waters. Within this family, the genus Nicolea, which comprises 30 accepted species, has been widely reported around the world, yet only a single species has been recorded in Chinese waters. Here we describe a new species Nicolea qingdaoensis sp. nov., collected from Qingdao, China.

The new species is distinguished from congeners by a combination of morphological characters: presence of eyespots; two pairs of branchiae on segment 2–3, with the first pair much larger than the second; 17 thoracic notopodia; ventral shields on segment 2 to 17; completely intercalated double rows of uncini starting from segment 11; genital papillae on segments 6 and 7 of equal length but sexually dimorphic, small spherical in females and digitiform in males.

Phylogenetic analyses based on the concatenated dataset of cox 1, 16S, 18 S, 28 S and H 3 genes revealed that N. qingdaoensis sp. nov., was sister to the clade including N. venustula (Montagu, 1819) from Mediterranean Sea, and N. gracilibranchis (Grube, 1878) from Hawaii and an unidentified Nicolea from Redondo Beach, California, USA. Additionally, we provided the complete mitochondrial genome of the new species.