Two new species of the genus Halichoanolaimus (Nematoda, Selachinematidae) from the intertidal zone of the Yellow Sea, China

Two new marine nematode species belonging to the genus Halichoanolaimus from the intertidal zone of the Yellow Sea are described. Halichoanolaimus sinensis sp. nov. is characterized by amphideal fovea with 2.5-3.0 turns, 20-27 degrees%o of corresponding body diameters; spicules curved, middle portion broad, tapering distally, 1.4-1.5 cloacal body diameters long; gubernaculum slender consisting of two detached lateral pieces tapering distally; 10-13 papilliform precloacal supplements in two groups, the posterior three supplements smaller and closer to each other, the remaining supplements larger and widely spaced; tail conico-cylindrical with a half cylindrical portion. The second new species, Halichoanolaimus zhangi sp. nov. is distinct by having lateral differentiation present except in anterior half of pharynx which has even punctations, amphideal fovea with 3.0-3.3 turns, spicules curved, gradually narrowing from proximal to distal end with pointed tip, 7 papilliform precloacal supplements, gradually increasing the spacing distance forward, two rows of subventral conical setae situated at the precloacal region, tail elongated, filiform. An updated key to 30 valid species of Halichoanolaimus is provided.