A new species of Ascolaimus Ditlevsen, 1919 (Nematoda: Axonolaimidae) from the intertidal zone of the Bohai Sea, China

A new free-living marine nematode species of the genus Ascolaimus is described. Ascolaimus ruyiensis sp. nov. was found from the intertidal sediments of Qinhuangdao, Hebei Province, China. It is characterized by the large total body length (2423-2727 μm), the high body length/diameter a (a = 74-81) and the presence of precloacal supplements. This new species could be distinguished from other species by the combination of its features: body size, length of cephalic setae, structures of spicules and gubernaculum, precloacal supplements. An updated dichotomous key is provided for three species of Ascolaimus, including the new species.