A new species of <i>Pista</i> (Annelida: Polychaeta: Terebellidae) from shallow waters of Shizugawa Bay, Sanriku Coast, Japan

A new species of the genus Pista (Annelida: Polychaeta: Terebellidae) was found on a boulder bottom in shallow waters of of Shizugawa Bay, Sanriku coast, northern Honshu, Japan. Individuals of this species measure 5 to 10 cm long and 3 to 5 mm wide. There are two pairs of branchiae on segments 2 and 3, each with an annulated long stalk and many dichotomous branches. The peristomium and segment 3 have elongate, semi-circular lateral lobes, segments 2 and 4 each have small lobes, segments 5 and 6 have very small lobes inserted between the neuropodium and ventral pad. Individuals of the new species have 17 pairs of notopodia from segment 4 and conical nephridial papillae on segments 6 and 7. The new Japanese species differs from all known species in the structure of the branchiae and the lateral lobes of anterior chaetigers