One new species of Oxyonchus ( ) (Enoplida: Nematoda) from the Yellow Sea of China

Abstract

During the diversity assessment of marine nematodes in the China seas, a new species of Oxyonchus (Filipjev, 1927) De Coninck & Schuurmans Stekhoven 1933 was discovered from the Yellow Sea of China. O. boucheri sp. nov. is characterized by cuticle smooth; mouth opening surrounded by three lips separated by deep clefts; cephalic region with developed cephalic capsule; mandibles arch-shaped, rods linked with anteriorly transverse bar, two subventral teeth extend to the mandibles' anterior ends; thick outer and inner labial setae; six files of 2–4 cervical setae; conico-cylindrical tail without terminal seta; curved spicules with tapered distal ends; gubernaculum with dorso-caudal apophysis; a ventral tubular and 6–8 pairs subventral spinous precloacal supplements. The new species differs from other 17 congeners mainly in its conical inner and thick outer labial setae (vs. slender labial setae), files of 2–4 cervical setae present (vs. cervical setae absent), slender spicules with tapered distal ends (vs. spicules with capitulum), both ventral tubular and subventral spinous precloacal supplements (vs. only tubular supplement in males). Updated dichotomous key to the genus Oxyonchus were provided.