Morphological and molecular study of Longicollum pagrosomi Yamaguti, 1935 (Acanthocephala: Pomphorhynchidae) from the barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel) (Perciformes: Oplegnathidae) in the East China Sea

Longicollum pagrosomi Yamaguti, 1935 (Acanthocephala: Pomphorhynchidae) collected from the barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel) (Perciformes: Oplegnathidae) in the East China Sea (off Zhoushan Islands) was studied using light and scanning electron microscopy. The SEM observations revealed for the first time the presence of about 28 well-developed sensory papillae arranged in a circle on the copulatory bursa. In addition, L. pagrosomi was characterised using molecular methods by sequencing of the internal transcribed spacer (ITS) of the ribosomal DNA based on the newly collected material. Longicollum pagrosomi is the first species of the genus with the ITS region sequenced for the purpose of species identification. These new morphological and molecular data contributed to a reliable and accurate specific identification and differentiation of species.