Exploring Neotropical anuran parasites: a morphological, life cycle and phylogenetic study of Catadiscus marinholutzi (Trematoda: Diplodiscidae)

Abstract

Abstract

Hidden in plain sight: novel molecular data reveal unexpected genetic diversity among paramphistome parasites (Digenea: Paramphistomoidea) of European water frogs

“…Our reconstruction based on the conservative 28S gene did not support the monophyly of the family Cladorchiidae (sensu Alves et al, 2020), although it was previously suggested (nonetheless, only on the basis of weak support). Even though Opisthodiscus and Megalodiscus share similar morphological traits (e.g., 2 testes, and an oesophagus that is shorter than the pharynx, Sey, 1991), recent phylogenetic analyses based on molecular data (Alves et al, 2020;Queiroz et al, 2021;and this study) suggest that these 2 genera are in paraphyly, and while the position of Opisthodiscus is nested within Diplodiscidae (i.e., a sister position to species of the genus Diplodiscus), Megalodiscus is positioned within Cladorchiidae. Thus, we can only assume that convergent adaptation to amphibian hosts evolved among paramphistomoids in different geographical regions; however, to fully resolve the classification of cladorchiids, more comprehensive morphological evaluation is required.…”

“…Although, the monophyly of Diplodiscidae was not fully supported by Queiroz et al . ( 2021 ), the current addition of Opisthodiscus into phylogeny helps to shed more light on the relationships within this family. Moreover, with further addition of (still missing) molecular data from other genera from the family Diplodiscidae (i.e., Progonimodiscus Vercammen-Grandjean, 1960 (in frogs from Africa), Dermatemytrema Price, 1937 (in turtles from North America), Pseudodiplodiscus Manter, 1962 (in fish from South America) and Australodiscus Sey, 1983 (in frogs from Oceania – Australia) (Sey, 1991 ; Jones, 2005 )) might help to finally resolve relationships of the diplodiscids to the cladorchiids, and further elucidate the historical dispersion routes and diversification within diplodiscids.…”

“…The distribution and diversity of paramphistome parasites of frogs were investigated to some degree in the past; however, little is known about their genetic diversity in this group of hosts. Publicly available sequence data on diplodiscid parasites of frogs are limited and include only several partial sequences of genes coding ribosomal subunits for 2 Diplodiscus species ( D. mehrai Pande, 1937 and D. japonicus (Yamaguti, 1936) from Besprozvannykh et al ., 2018 ) and 1 species of Catadiscus ( C. marinholutzi Freitas & Lent, 1939 from Queiroz et al ., 2021 ). To date, there is no molecular data for any species of Opisthodiscus , which could be used to assess phylogenetic relationships based on DNA sequences.…”

“…Besprozvannykh et al (2018) andQueiroz et al (2021) investigated more thoroughly the phylogenetic relationships among diplodiscids using available genetic markers; however, neither study fully tackled the intraspecific variability in the respective species. Regarding mitochondrial DNA (mtDNA), the complete mitogenome of D. nigromaculati Wang, 1977 from the east Asian water frog species P. nigromaculatus(Hallowell, 1861) was recently added to public databases; however, these data have not yet been utilized in any published work.…”

Phylogenetic position of Gorgoderina parvicava Travassos, 1922 (Digenea: Gorgoderidae), a parasite of Leptodactylus labyrinthicus (Spix, 1824) (Anura: Leptodactylidae) in Brazil

“…Studies have demonstrated that molecular analysis is an important tool for the identification and phylogenetic analyses of trematodes (Gomes et al, 2013;Müller et al, 2021;Queiroz et al, 2021;Franceschini et al, 2021). Here, we provide the morphological and the first molecular assessment of G. parvicava from L. labyrinthicus in Brazil using the mitochondrial gene cytochrome c oxidase I (COI) and the large subunit of the 28S ribosomal gene.…”