A molecular phylogenetic appraisal of the acanthostominesAcanthostomumandTimoniellaand their position within Cryptogonimidae (Trematoda: Opisthorchioidea)

Abstract

The phylogenetic position of three taxa from two trematode genera, belonging to the subfamily Acanthostominae (Opisthorchioidea: Cryptogonimidae), were analysed using partial 28S ribosomal DNA (Domains 1–2) and internal transcribed spacers (ITS1–5.8S–ITS2). Bayesian inference and Maximum likelihood analyses of combined 28S rDNA and ITS1 + 5.8S + ITS2 sequences indicated the monophyly of the genus Acanthostomum (A. cf. americanum and A. burminis) and paraphyly of the Acanthostominae. These phylogenetic relationships were consistent in analyses of 28S alone and concatenated 28S + ITS1 + 5.8S + ITS2 sequences analyses. Based on molecular phylogenetic analyses, the subfamily Acanthostominae is therefore a paraphyletic taxon, in contrast with previous classifications based on morphological data. Phylogenetic patterns of host specificity inferred from adult stages of other cryptogonimid taxa are also well supported. However, analyses using additional genera and species are necessary to support the phylogenetic inferences from this study. Our molecular phylogenetic reconstruction linked two larval stages of A. cf. americanum cercariae and metacercariae. Here, we present the evolutionary and ecological implications of parasitic infections in freshwater and brackish environments.

New morphological and molecular data for Xystretrum solidum (Gorgoderidae, Gorgoderinae) from Sphoeroides testudineus (Tetraodontiformes, Tetraodontidae) in Mexican waters

“…However, based on COI phylogenetic topology plus 28S, it is possible to suggest a diversification of the most recent common ancestor of Xystretrum from freshwater to marine environments, and a subsequent diversification in tetraodontiforms via host-switching events. A similar evolutionary process of transition from freshwater to marine environments has also been suggested for other platyhelminth groups (e.g., Álvarez-Presas et al 2008;Van Steenkiste et al 2013;Martínez-Aquino et al 2017).…”

Metazoan parasite communities of three endemic cichlid fish species from the upper Grijalva River, Chiapas, Mexico

“…These differences could be a consequence of the abundance of intermediate hosts in the region, size, diet and geographic range of examined hosts. The feeding habits of V. breidohri and V. hartwegi consist mainly of aquatic plants, detritus and invertebrates (Rodiles-Hernández and González-Díaz, 2006, Ceballos et al, 2016 that could have favored the consumption of snails, such as Pyrgophorus coronatus (Pfeiffer, 1840), Biomphalaria obstructa Morelet, 1849 and B. helophila (d'Orbigny, 1835), which are present in the region and involved in the life cycles of many metazoans (see Aguirre- Macedo et al, 2011Macedo et al, , 2016Martínez-Aquino et al, 2017). On the other hand, C. grammodes feeds mainly on aquatic insects (e.g., Trichoptera, Odonata, Megaloptera) and small fish.…”

“…type 2) (Aguirre-Macedo et al, 2011, 2016. The feeding habits of V. breidohri and V. hartwegi consist mainly of aquatic plants and a wide variety of snails (Gómez-González et al, 2015), that could have favoured the parasite infections of intermediate hosts (e.g., snails P. coronatus, B. obstructa and B. helophila), involved in the life cycles of many metazoans (Aguirre-Macedo et al, 2011, 2016Martínez-Aquino et al, 2017). On the other hand, C. grammodes feeds mainly on aquatic insects (e.g., Trichoptera, Odonata, Megaloptera) and small fish that might produce little variation on their community descriptors (species richness, diversity) and infection parameters (mean abundance) between host species (Violante-González et al, 2008a,b;Gómez-González et al, 2015 Kennedy, 1996;Salgado-Maldonado et al, 2005).…”

“…The feeding habits of V. breidohri and V. hartwegi consist mainly of aquatic plants, detritus and invertebrates ( Rodiles-Hernández and González-Díaz, 2006 , Ceballos et al, 2016 ) that could have favored the consumption of snails, such as Pyrgophorus coronatus (Pfeiffer, 1840), Biomphalaria obstructa Morelet, 1849 and B . helophila (d’Orbigny, 1835), which are present in the region and involved in the life cycles of many metazoans (see Aguirre-Macedo et al, 2011 , 2016 ; Martínez-Aquino et al, 2017 ). On the other hand, C .…”

“…The feeding habits of V. breidohri and V. hartwegi consist mainly of aquatic plants and a wide variety of snails ( Gómez-González et al, 2015 ), that could have favoured the parasite infections of intermediate hosts (e.g., snails P. coronatus , B. obstructa and B . helophila ), involved in the life cycles of many metazoans ( Aguirre-Macedo et al, 2011 , 2016 ; Martínez-Aquino et al, 2017 ). On the other hand, C .…”