Morphology and molecular characterization of Demidospermus spirophallus n. sp., D. prolixus n. sp. (Monogenea: Dactylogyridae) and a redescription of D. anus in siluriform catfish from Brazil

Abstract

The present study describes Demidospermus spirophallus n. sp. and Demidospermus prolixus n. sp. (Monogenea, Dactylogyridae) from the siluriform catfish Loricaria prolixa Isbrücker & Nijssen, 1978 (Siluriformes, Loricariidae) from the state of São Paulo, Brazil, supported by morphological and molecular data. In addition, notes on the circumscription of the genus with a redescription of Demisdospermus anus are presented. Demidospermus spirophallus n. sp. differed from other congeners mainly because of the morphology of the male copulatory organ (MCO), which exhibited 2½ counterclockwise rings, a tubular accessory piece with one bifurcated end and a weakly sclerotized vagina with sinistral opening. Demidospermus prolixus n. sp. presents a counterclockwise-coiled MCO with 1½ rings, an ovate base, a non-articulated groove-like accessory piece serving as an MCO guide, two different hook shapes, inconspicuous tegumental annulations, a non-sclerotized vagina with sinistral opening and the absence of eyes or accessory eyespots. The present study provides, for the first time, molecular characterization data using the partial ribosomal gene (28S) of two new species of Demidospermus from Brazil (D. spirophallus n. sp. and D. prolixus n. sp.), and Demidospermus anus from Loricariichthys platymetopon Isbrücker & Nijssen, 1979 collected in the Upper Paraná River floodplain, Brazil. Additionally, a revision of the species composition of this genus and others that occur in catfish is proposed to elucidate problems with their circumscription. The Brazilian species of Demidospermus clustered together as sister taxa among Neotropical dactylogyrids from siluriforms. The morphological characterization of D. spirophallus n. sp. and D. prolixus n. sp., and the molecular data of the three species in the present study will extend knowledge about this monogenean genus from the Neotropical region, and provide new information for future phylogeny studies.

A new genus and four new species of dactylogyrids (Monogenea), gill parasites of pimelodid catfishes (Siluriformes: Pimelodidae) in South America and the reassignment of Urocleidoides megorchis Mizelle et Kritsky, 1969

“…Demidospermus is one of the most speciose and taxonomically problematic genera of dactylogyrids from Ne-otropical siluriforms (families Auchenipteridae, Loricariidae and Pimelodidae), with 30 species described so far (Acosta et al 2018, Franceschini et al 2018. Even though most species (23) have been described from pimelodids, it seems that the genus is in fact specific to loricariids and taxa from other catfish families belong to other genera, not yet formally proposed (Mendoza-Palmero et al 2015, Acosta et al 2018, Franceschini et al 2018.…”

“…A total of 43 partial sequences of the 28S rRNA gene of dactylogyrid parasites from siluriforms previously published (Mendoza-Palmero et al 2015, Acosta et al 2017, Franceschini et al 2018, Yamada et al 2018 along with three species of the Diplectanidae (used as outgroup), were retrieved from GenBank (see Fig. 5) and aligned with the longest newly generated sequences of U. megorchis and A. travassosi.…”

<b>Biodiversity and ecology of the parasitic infracommunities of <i>Loricaria prolixa</i> (Siluriformes: Loricariidae) from the Tietê-Batalha Basin, SP, Brazil

“…Franceschini et al (2017), Clinostomum detruncatum Braun, 1899 (metacercariae), Diplostomidae gen. sp.…”

Monogeneans of the catfish Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae) from the Brazilian Amazon, with a description of a new species of Ameloblastella Kritsky, Mendoza-Franco & Scholz, 2000 (Monogenea: Dactylogyridae)

“…The dactylogyrid genera Amelloblastella , Demidospermus Suriano, 1983and Scleroductus Jara & Cone, 1989 include parasites mostly infesting catfish (Siluriformes) from South and Central America (Mendoza-Franco & Scholz, 2009;Kritsky et al, 2013;Mendoza-Franco et al, 2016). Currently, Amelloblastella and Demidospermus, both parasitic on the gills, comprise 10 and 30 valid species, respectively (Mendoza-Franco & Scholz, 2009;Mendoza-Franco et al, 2016;Acosta et al, 2017;Franceschini et al, 2018). Scleroductus, which parasitises the body surface mainly from pimelodid fishes (Pimelodidae) in South America, allocates only three valid species (Kritsky et al, 2013).…”