Taxonomy Of Cucullanidae(Ascaridida: Seuratoidea) From The Marine Fishes In The Chinese Waters

Nematodes of Cucullanidae Cobbold, 1864(Nematoda: Ascaridida) commonly occur in the digestive tract of various teleost fishes and rarely in aquatic turtles throughout the world. Cuculanid infections can affect the growth rate and health of the hosts, make them more vulnerable to diseases and even result in mortalities.During a helminthological survey of Chinese marine fishes, large numbers of cucullanid nematodes were collected. In order to accurately identify these parasites to the species level, the integrated approaches were used, including light and scanning electron microscopy, sequencing and analysing ribosomal [small ribosomal DNA(18S) and internal transcribed spacer(ITS)] and mitochondrial [cytochrome c oxidase subunit 1(cox1)] target regions, respectively. The results of detailed studies of these parasites are presented below.Dichelyne J?gerski?ld, 19021) Dichelyne(Dichelyne) breviculus Li, Xu & Zhang, 2014 collected from Dendrophysa russelii(Cuvier)(Perciformes: Sciaenidae), Trypauchen vagina(Bloch & Schneider)(Perciformes: Taenioididae) and Acentrogobius caninus(Valenciennes)(Perciformes: Taenioididae) in the South China Sea, is described using both light and scanning electron microscopy. The specimens of D.(D.) breviculus collected from the three different hosts were also characterised using molecular methods by sequencing and analysing ribosomal [small ribosomal subunit(18S r DNA) and internal transcribed spacer(ITS)] and mitochondrial [cytochrome c oxidase subunit 1(cox1)] target regions.2) Dichelyne(Cucullanellus) pleuronectidis(Yamaguti, 1935) collected from Pleuronichthys cornutus(Temminck & Schlegel)(Pleuronectiformes: Pleuronectidae) in the East China Sea; Dichelyne(Dichelyne) spinigerus Moravec, Khosheghbal & Pazooki, 2014 collected from Pennahia macrocephalus Tang(Perciformes: Sciaenidae) in the Taiwan Strait, were redescribed using light and scanning electron microscopy. In addition, specimens of Dichelyne(Dichelyne) pleuronectidis were characterised using molecular methods by sequencing and analysing the internal transcribed spacer(ITS) of the ribosomal DNA to test whether the present material with broad range of morphological variability, represents a complex of sibling species or a single species. The results of molecular analyses proved that the differences in the intestinal ceacum and deirids should be considered as intraspecific variation and that the nematode material collected from Pleuronichthys cornutus(Temminck & Schlegel) in the East China Sea represented a single species, Dichelyne(Dichelyne) pleuronectidis.Cucullanus Müller, 17773) Cucullanus extraneus sp. nov. collected from Pomacanthus maculosus(Forssk?l)(Perciformes: Pomacanthidae) in the Persian Gulf; Cucullanus hainanensis Xu, Zhang & Li, 2014 collected from Muraenichthys gymnopterus(Bleeker)(Anguilliformes: Ophichthidae) in the South China Sea; C. sargocentronus sp. n. collected from Dispinus ruber(Forssk?l)(Beryciformes: Holocentridae) in the Taiwan strait were reported; Cucullanus singulus sp. nov. collected from Hoplobrotula armata Temminck et Schlege(Ophidiiformes : Ophidiidae) in the South China Sea. Of them, Cucullanus hainanensis was characterized using molecular methods by sequencing and analysing the small subunit(18S) and the second internal transcribed spacer(ITS-2) of nuclear ribosomal DNA(r DNA).4) Cucullanus angeli Caba?as-Carranza & Caspeta-Mandujano, 2007 collected from Caesio caerulaureus Lacepède(Perciformes: Caesionidae) in the South China Sea; C Cucullanus anguillae Wang & Lin, 1975 collected from Anguilla japonica Temminck et Schlegel(Anguilliformes: Anguillidae); C. bourdini Petter & Le Bel, 1992 collected from Caesio xanthonota Bleeker(Perciformes: Caesionidae) in the Taiwan strait; C. filiformis Yamaguti, 1935 collected from Astroconger myriaster(Brevoort)(Congridae: Rhynchoconger) in the East China Sea; Cucullanus hians(Dujardin, 1845) collected from Uroconger lepturus(Richardson)(Anguilliformes: Congridae) in the South China Sea; Cucullanus pimelodellae Moravec, Kohn and Fernandes, 1993 collected from Arius sinensis Lacepede(siluriformes: Ariidae) in the Taiwan strait; Cucullanus sigani Yamaguti, 1954 collected from Apolemichthys trimaculatus(Cuvier)(Perciformes: Pomacanthidae) in the Taiwan strait were redescribed using light microscopy.