Morphological and genetic characterization of Hysterothylacium zhoushanensis sp. nov. (Ascaridida: Anisakidae) from the flatfish Pseudorhombus oligodon (Bleeker) (Pleuronectiformes: Paralichthyidae) in the East China Sea

Abstract

Hysterothylacium zhoushanensis sp. nov. collected from the intestine of the flatfish Pseudorhombus oligodon (Bleeker) (Pleuronectiformes: Paralichthyidae) in the East China Sea is described and illustrated by light and scanning electron microscopy. The new species can be easily distinguished from its congeners by the presence of remarkable lateral alae, the very short intestinal caecum, the unusually long ventricular appendix (ratio of intestinal caecum to ventricular appendix 1:8.74-23.8), the short spicules (0.58-0.81 mm long, representing 1.70-2.08 % of body length) and the number and arrangement of male caudal papillae (35-42 pairs in total, arranged as 26-32 pairs of precloacal, two pairs of paracloacal and six to eight pairs of postcloacal). In addition, the adults and the putative third-stage larvae identified morphologically of the new species are characterised by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA. The result reveals that they are homogeneous genetically, and all belong to the same species. Molecular analysis by comparing the ITS gene of H. zhoushanensis sp. nov. with these species of Hysterothylacium available in GenBank also seem to support the validity of the new species based on the morphological observation.

Detection of ascaridoid nematode parasites in the important marine food-fish Conger myriaster (Brevoort) (Anguilliformes: Congridae) from the Zhoushan Fishery, China

“…Four different morphotypes of Hysterothylacium spp. larvae were distinguished, including the Hysterothylacium larval type of Smith (1983) [ 24 ] with 28 individuals, Hysterothylacium larval type of Guo et al (2014) [ 27 ] with 23 individuals, Hysterothylacium larval type of Li et al (2012) [ 25 ] with 11 individuals and Hysterothylacium larval type IV of Shamsi et al (2013) [ 26 ] with 447 individuals. Only three third-stage larvae of Raphidascaris , identified morphologically as Raphidascaris larval type of Zhao et al (2016) [ 22 ], were found in the present study (see Table 2 for details).…”

“…g , h Hysterothylacium larval type of Guo et al (2014) [ 27 ]. i , j Hysterothylacium larval type of Li et al (2012) [ 25 ]. k , l Raphidascaris larval type of Zhao et al (2016) [ 22 ]

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“…The Column Genomic DNA Isolation Kit (Shanghai Sangon, China) was employed to extract the genomic DNA of each worm according to the manufacturer’s instructions. The ITS1-5.8S-ITS2 region was amplified by PCR using the primers NC5 (5'-GTA GGT GAA CCT GCG GAA GGA TCA T-3') and NC2 (5'-TTA GTT TCT TTT CCT CCG CT-3') [ 28 ] under the cycling conditions described previously [ 25 ]. PCR products were checked on GoldView-stained 1.5% agarose gel and purified by the Column PCR Product Purification Kit (Shanghai Sangon, China).…”

Molecular identification of Anisakis and Hysterothylacium larvae in marine fishes from the East China Sea and the Pacific coast of central Japan

“…H. amoyense (Contracaecum muraenesoxi has been synonymized as H. amoyense) (Knoff et al, 2012;Li et al, 2008), which was found only in the China-Taiwan Strait to date (Fang et al, 2010), was also identified in the East China Sea with 5% relative abundances. In Chinese waters, Hysterothylacium genus larvae have been found from the marine fish in the Bohai and Yellow Sea, the East China Sea and the South China Sea (Guo et al, 2014;Li et al, 2012;Li et al, 2013;Shih, 2004;Xu et al, 2014;Zhu et al, 2007). Larvae of Hysterothylacium are common parasites of marine, estuarine and freshwater fishes worldwide.…”

Ege Bölgesi Akarsularında Yakalanan Avrupa Yılan Balıklarında (Anguilla anguilla Linnaeus, 1758) Raphidascaris acus Bloch, 1779 (Nematoda: Anisakidae)’un İlk Moleküler Karakterizasyonu

“…However, to date there has not been any study regarding molecular characterization of R. acus from fish caught off the Turkish waters. Recently, molecular techniques, using DNA sequencing of the nuclear ribosomal DNA spacers, have been proven to be particularly useful for the accurate identification of ascaridoid nematodes at the species level for eggs, larvae, and adults [5][6][7][8][9][10][11][12] . Nevertheless, before the present study, there had been no reports of characterizing the R. acus from the Turkish waters using well-defined internal transcribed spacers (ITS1 and ITS2) and 5.8S region sequence.…”