Molecular systematics and type-material-based redescription of Metarhadinorhynchus lateolabracis, with taxonomic revisions of Metarhadinorhynchus, Indorhynchus, and Neotegorhynchus (Acanthocephala: Palaeacanthocephala)
Kita, Y.; Nitta, M.; Kajihara, H. (2024). Molecular systematics and type-material-based redescription of Metarhadinorhynchus lateolabracis, with taxonomic revisions of Metarhadinorhynchus, Indorhynchus, and Neotegorhynchus (Acanthocephala: Palaeacanthocephala). Acta Parasitol. 69(3): 1411-1425. https://dx.doi.org/10.1007/s11686-024-00876-1
In: Acta Parasitologica. Witold Stefanski Institute of Parasitology/de Gruyter: Warszawa, Berlin. ISSN 1230-2821; e-ISSN 1896-1851, more
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| Author keywords |
Molecular phylogeny, Morphology, Echinorhynchida, Polymorphida, seabass |
| Authors | | Top |
- Kita, Y.
- Nitta, M.
- Kajihara, H.
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| Abstract |
Purpose: Molecular phylogenetics has been improving the acanthocephalan systematics, yet numerous taxa remain unex?plored. The palaeacanthocephalan Metarhadinorhynchus Yamaguti, 1959 and its type species M. lateolabracis Yamaguti, 1959 are such to-be-explored taxa. We aim to refne (i) the systematic placement, (ii) the morphological circumscription, and (iii) the taxonomic components of the genus. We also aim to examine the taxonomic status of the species that have been assigned to the genus.Methods: Morphological observations on newly collected specimens as well as the type material of Metarhadinorhyn?chus lateolabracis were conducted. Also, molecular phylogenetic analyses with maximum-likelihood method and Bayesian inference were performed based on freshly collected specimens. Nominal species that have at least once been assigned in Metarhadinorhynchus, as well as a related form, Gorgorhynchus lateolabri Yin and Wu, 1984, are taxonomically re-evaluated based on literature information.Results: Our re-examination of the type material of M. lateolabracis revealed that the number of cement glands is six, instead of eight as described and illustrated in the original description. In the resulting phylogenetic tree, M. lateolabracis was nested in Isthmosacanthidae. Gorgorhynchoides Cable and Linderoth, 1963 was found to be a junior synonym of Metarhadinorhyn?chus. Taxonomic re-evaluations of six nominal species that have once belonged in Metarhadinorhynchus led to modifcations of generic diagnoses for Indorhynchus Golvan, 1969 and Neotegorhynchus Lisitsyna, Xi, Orosová, Barčák, and Oros, 2022.Conclusions Metarhadinorhynchus has been assigned to Leptorhynchoididae (Echinorhynchida), but our study now locates it in Isthmosacanthidae (Polymorphida). We propose 13 new combinations of specifc names in Metarhadinorhynchus and three in Indorhynchus. Metarhadinorhynchus lateolabri (Yin and Wu, 1984) comb. nov. may be synonymous with M. ori?entalis (Wang, 1966) comb. nov. |
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