The morphological and molecular description of Neoechinorhynchus (Neoechinorhynchus) poonchensis sp. n. from Schizothorax richardsonii (Gray) in Poonch, Jammu and Kashmir, India.

Specimens of Neoechinorhynchus (Neoechinorhynchus) poonchensis sp. n. are described from Schizothorax richardsonii (Gray) in the Poonch River, Jammu and Kashmir. Specimens are thick-walled with dissimilar dorsal and ventral para-receptacle structures, anteriorly manubriated hooks, two giant nuclei in each lemniscus and many subcutaneousy. The lemnisci barely overlap the larger anterior testis, the cement gland has eight giant nuclei, and the seminal vesicle is large with thin walls. The vagina is unremarkable but the long uterus is made up of four specialised regions. Neoechinorhynchus rigidus (Van Cleave, 1928), resembles N. poonchensis sp. n. It is distinguished from N. poonchensis sp. n. by having smaller trunk, proboscis, and male reproductive structures, equal testes, unequal lemnisci with three giant nuclei each, and much larger anterior proboscis hook (130 µm in males) than that originally described by Van Cleave (1928) (70 µm in a female). Anterior hook length alone is sufficient to conclude that the N. rigidus of Datta (1937) is not the same species as the N. rigidus of Van Cleave (1928). Van Cleave's (1928) species remains valid and that of Datta (1937) is considered a different species named Neoechinorhynchus pseudorigidus sp. n., herein. Micropores of N. poonchensis sp. n. have variable distribution in different trunk regions and the Energy Dispersive X-ray analysis demonstrated higher levels of sulfur and lower levels of calcium and phosphorus. Sequences of the 18S rDNA gene from nuclear DNA, and cytochrome c oxidase subunit I (cox1) from mitochondrial DNA of N. poonchensis sp. n. were amplified and aligned with other sequences available on GenBank. Maximum likelihood (ML) and Bayesian inference (BI) analyses inferred for 18S rDNA and cox1 showed that N. poonchensis sp. n. was nested in a separate clade.

Morphological and molecular description of Rhadinorhynchus laterospinosus Amin, Heckmann & Ha, 2011 (Acanthocephala, Rhadinorhynchidae) from marine fish off the Pacific coast of Vietnam.

Rhadinorhynchus laterospinosus Amin, Heckmann & Ha, 2011 (Rhadinorhynchidae) was described from a single female collected from a trigger fish, Balistes sp. (Balistidae) from the northern Pacific coast of Vietnam in Halong Bay, Gulf of Tonkin. More recent collections of fishes in 2016 and 2017 revealed wider host and geographical distributions. We report this Acanthocephala from nine species of fish representing six families (including the original record from Balistes sp.) along the whole Pacific coast of Vietnam. The fish species are Alectis ciliaris (Carangidae), Auxis rochei (Scombridae), Auxis thazard (Scombridae), Leiognathus equulus (Leiognathidae), Lutjanus bitaeniatus (Lutjanidae), Megalaspis cordyla (Carangidae), Nuchequula flavaxilla (Leiognathidae), and Tylosurus sp. (Belonidae). We provide a complete description of males and females of R. laterospinosus, discuss its hook metal microanalysis using EDAX, and its micropores. Specimens of this species characteristically have lateral trunk spines bridging the anterior ring of spines with posterior field of ventral spines and a proboscis with 15-19 longitudinal alternating rows of 21-26 hooks each varying with host species. We demonstrate the effect of host species on the distribution and size of the trunk, proboscis, proboscis hooks, trunk spines, and reproductive structures. The molecular profile of this acanthocephalan, based on 18S rDNA and cox1 genes, groups with other Rhadinorhynchus species and further seems to confirm the paraphyly of the genus, which is discussed.

Acanthocephalans from fishes and amphibians in Vietnam, with descriptions of five new species.

Eight species of acanthocephalans are reported, and five are new. Specimens of Neoechinorhynchus (Hebesoma) manubrianus Amin, Ha & Ha, 2011 were similar to the original description. Neoechinorhynchus (Hebesoma) spiramuscularis n. sp. (Neoechinorhynchidae), from Xenocypris davidi, has a unique proboscis receptacle wrapped in a spiral muscular layer, and an undulating flask-shaped lemnisci, as well as double para-receptacle structures. Heterosentis mongcai n. sp. (Arhythmacanthidae), from Acreichthys sp., has a small fusiform trunk with an unarmed cone and anterior trunk spines, and a proboscis with two circles of rooted apical hooks and 3-4 circles of rooted posterior spines as well as a para-receptacle-like structure at the posterior end. The poorly known Filisoma indicum Van Cleave, 1928 is fully described and illustrated for the first time. Acanthocephalus parallelcementglandatus n. sp. (Echinorhynchidae), from Clarias batrachus, is distinguished from other species of Acanthocephalus by its small fusiform trunk and parallel tubular cement glands. Pseudoacanthocephalus coniformis n. sp. (Echinorhynchidae), from Hylarana sp., is distinguished from other species by having an anterior trunk collar and staggered prominent filiform cement glands, among other features. Cathayacanthus spinitruncatus n. sp. (Rhadinorhynchidae), from Leiognathus equulus, is distinguished from the only two known species of the genus by having a very long and slender proboscis with more than 50 hooks per row and a totally spined trunk. The generic diagnosis of Cathayacanthus Golvan, 1969 is emended. Rhadinorhynchus johnstoni Golvan, 1969 (Rhadinorhynchidae) perfectly fits the only complete description of that species from the Fiji Islands.