Morphological and molecular study of the poorly known species Pseudanisakis rajae (Yamaguti, 1941) (Nematoda: Acanthocheilidae) from elasmobranchs in the Yellow Sea and Taiwan Strait off the coast of China.

Ascaridoid nematodes identified as Pseudanisakis rajae (Yamaguti, 1941) were collected from the skates Bathyraja smirnovi (Soldatov & Pavlenko), Okamejei kenojei (Müller & Henle) and Raja pulchra Liu (Rajiformes: Rajidae) in the Yellow Sea and Taiwan Strait off the coast of China. Their examination using light microscopy and, for the first time, scanning electron microscopy revealed erroneous and previously unreported morphological features, necessitating the redescription of this little known species. In addition, specimens of P. rajae collected from the three different hosts were characterised using molecular methods by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA. These new morphological and molecular data enabled an updated diagnosis of this nematode and the presentation of an identification key to the species of Pseudanisakis Layman & Borovkova, 1926.