Hidden diversity of the most basal tapeworms (Cestoda, Gyrocotylidea), the enigmatic parasites of holocephalans (Chimaeriformes)
| Autor: | Hsuan-Wien Chen, Daniel Barčák, Martina Orosová, Tomáš Scholz, Mikuláš Oros, Pasaikou Sonko, Roman Kuchta, Chia Kwung Fan |
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| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Biogeography Science Cestoda Zoology 010603 evolutionary biology 01 natural sciences 18S ribosomal RNA Article 03 medical and health sciences Genus 28S ribosomal RNA RNA Ribosomal 18S Animals Phylogeny Multidisciplinary biology Ecology Fishes biology.organism_classification Type species 030104 developmental biology Medicine Chimaera (genus) RNA Helminth Living fossil |
| Zdroj: | Scientific Reports Scientific Reports, Vol 11, Iss 1, Pp 1-11 (2021) |
| ISSN: | 2045-2322 |
| Popis: | Gyrocotylideans are evolutionary ancient parasitic flatworms, and like their hosts—a relict group of holocephalan fishes (Chimaeriformes)—they are considered to be “living fossils” of a vanished past. However, the species diversity, host associations and biogeography of these most basal tapeworms are poorly known. Herein, we provide evidence of a conspicuous contrast between the genetic and morphological data based on an examination of newly collected and properly processed Gyrocotyle specimens (hologenophores) isolated from holocephalans off Taiwan and Argentina. Our molecular data, inferred from three genes (COI, 28S rRNA, 18S rRNA), showed unexpected genetic interrelationships among isolates of the genus Gyrocotyle, because each of the four genotypes from Taiwan clustered with isolates of distinct gyrocotylideans from the North Atlantic. Three genotypes of Gyrocotyle from Taiwan were morphologically almost indistinguishable from each other but represented distinct genetic lineages; a single specimen of Gyrocotyle sp. genotype 4 exhibited a clear genetic and morphological distinctness, though its formal description as a new species would be premature. Additionally, specimens of Gyrocotyle rugosa Diesing, 1850, from the type host Callorhinchus callorynchus from Argentina, provided the first genetic data on the type species of the genus and enabled us to characterise it, which is necessary for future taxonomic studies. The finding of some specimens of Gyrocotyle sp. genotype 3 in Chimaera phantasma, and another one in C. cf. argiloba, together with the putative conspecificity of an unidentified gyrocotylidean from Callorhinchus milii off Australia and G. rugosa from C. callorynchus off Argentina, represent evidence that one gyrocotylidean species may parasitise more than one holocephalan host species. Existing taxonomic problems and conflicts between morphological and molecular data on species of Gyrocotyle can only be resolved if hologenophores from type hosts and localities of nominal taxa are properly characterised genetically and morphologically. |
| Databáze: | OpenAIRE |
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