Morphological and molecular characterization of larval trematodes infecting the assassin snail genusAnentomein Thailand

Abstract

The assassin snail genus Anentome is widespread in Southeast Asia, and is distributed all over the world via the aquarium trade. One species of genus Anentome, Anentome helena, is known to act as intermediate host of parasitic trematodes. This study investigates the taxonomic diversity of larval trematodes infecting A. helena and Anentome wykoffi in Thailand. Larval trematodes were identified by combining morphological and DNA sequence data (cytochrome c oxidase I and internal transcribed spacer 2). Species delimitation methods were used to explore larval trematode species boundaries. A total of 1107 specimens of Anentome sp. were collected from 25 localities in Thailand. Sixty-two specimens of A. helena (n = 33) and A. wykoffi (n = 29) were infected by zoogonid cercariae, heterophyid metacercariae and echinostome metacercariae, with an overall prevalence of 5.6% (62/1107) and population-level prevalences in the range of 0.0–22.3%. DNA sequence data confirmed that the larval trematodes belong to the families Echinostomatidae, Heterophyidae and Zoogonidae. As such, this is the first report of zoogonid cercariae and heterophyid metacercariae in A. helena, and echinostome metacercariae in A. wykoffi. Moreover, this study provides evidence of tentative species-level differentiation between Thai Echinostoma sp. and Cambodian Echinostoma mekongi, as well as within Echinostoma caproni, Echinostoma trivolvis and Echinostoma revolutum.

Morphological and DNA analyses reveal cryptic diversity in Anentome wykoffi (Brandt, 1974) (Gastropoda: Nassariidae), with descriptions of two new species from Thailand

“…This species is known from Sa Kaeo, Buriram and Surin provinces. Based on our morphological and DNA sequence analyses, we suggest that A. wykoffi in Chomchoei et al (2022) involves A. longispira sp. nov.…”

“…Anentome wykoffi (Brandt, 1974) – Chomchoei et al (2022), table 1, fig. 1, Ban Kong, Nong Ruea, Khon Kaen, Thailand; Khemmarat, Ubon Ratchathani, Thailand; Khong Chiam, Ubon Ratchathani, Thailand.…”

“…Anentome wykoffi (Brandt, 1974) – Chomchoei et al (2022), table 1, fig. 1, Dan, Kap Choeng, Surin, Thailand; Non Din Daeng, Buri Ram, Thailand; Aranyaprathet, Aranyaprathet, Sa Kaeo, Thailand.…”

“…Similarly, the present work shows that the use of the name ‘ A. wykoffi ’ in some previous papers must be corrected. This applies to A. wykoffi in Chomchoei et al (2022) that actually refers to A. longispira sp. nov., whereas species B in Strong et al (2017) is A. wykoffi s.s.…”

Molecular characterization and phylogeny based on ITS2 and 28S regions of rDNA of Microphallus sp. (Digenea: Microphallidae) parasitic in freshwater crabs of Manipur, India

“…In India, so far, only few microphallid taxa have been identi ed, namely: Levinseniella indica Lal 1936; Basantisia ramai Pande 1938; Pseudospeloterma indicum Murhar 1960; Mehraformes jabalpurensis Bharadwaj 1963; Spelotrema narii Rao 1965; Microphallus indicus Mukherjee and Ghosh 1967; Megalatriotrema hispidum Rao 1969 and S. chauhani Gupta and Jahan 1975 (Yamaguti 1971; Global Names Index, 2010; Goswami et al 2013).A variety of molecular techniques have increasingly been utilized for various taxonomic issues related to describing new species or strains, supplementing traditional methods for characterizing based on their morphological studies(Thompson et al 2004;Olson and Tkach 2005;Otachi et al 2015). These techniques can be used even from the larval stages in addition to the adult stage of a taxon(Jousson et al 1998;Rathinam et al 2012;Chomchoei et al 2022…”