First molecular assessment of the interrelationships of cladorchiid digeneans (Digenea: Paramphistomoidea), parasites of Neotropical fishes, including descriptions of three new species and new host and geographical records

Abstract

The first molecular assessment of phylogenetic relationships of cladorchiid digeneans (superfamily Paramphistomoidea Fischoeder, 1901) from freshwater fishes based on 28S rDNA, ITS2 and cox1 sequences reveals the subfamilies Dadayiinae Fukui, 1929 and Kalitrematinae Travassos, 1933 as non-monophyletic, whereas Dadaytrema Travassos, 1931 represented by three species is monophyletic. Fourteen species of cladorchiids were found in characiform, perciform and siluriform fishes in the Neotropical Region (Brazil and Peru), with numerous new host and geographical records. The first scanning electron micrographs of seven species are presented. Two new species of dadayiine and one new species of kalitrematine paramphistomes are described. Microrchis macrovarium sp. n. from Pimelodella cristata (Müller et Troschel) (type host), Tetranematichthys quadrifilis (Kner) and Pterodoras granulosus (Valenciennes) in Brazil and Peru differs from all three congeners in that the testes are directly tandem, not oblique, and that the ovary, between the caecal ends, is widely separated from the testes. Pronamphistoma philippei sp. n. from Heros sp. in Brazil is distinguished from the type and only species, Pronamphistoma cichlasomae Thatcher, 1992, by the absence of the anterior collar-like expansion present in the type species, the presence of extramural rather than intramural pharyngeal sacs, and the unusual development of the dorsal and ventral exterior circular muscle fibre series in the acetabulum. Pseudocladorchis romani sp. n. from P. granulosus (type host), Brachyplatystoma vaillantii (Valenciennes), Calophysus macropterus (Lichtenstein), Megalodoras uranoscopus (Eigenmann et Eigenmann) and Oxydoras niger (Valenciennes) in Brazil and Peru, is most similar to Pseudocladorchis nephrodorchis Daday, 1907 but differs in the shape of the testes (irregular, versus reniform in the latter species) and the size of the ovary (as large as, or larger than, the testes in the new species).

Endoparasite fauna of freshwater fish from the upper Juruá River in the Western Amazon, Brazil

“…Endoparasites P. romani and R. rondoni were found in high abundance in Pterodoras granulosus, and both showed high parasite load in the same host. Pseudocladorchis romani has already been reported parasitizing Pterodoras granulosus, in addition to Brachyplatystoma vaillantii, Oxydoras niger in Peru and Megalodoras uranoscopus have been reported in the state of Pará (Pantoja et al, 2019), but the authors did not report this parasite load for this organism nor its interaction with specimens of R. rondoni. The parasite load of R. rondoni has already been observed in Pterodoras granulosus in the intestinal lumen (Dias et al, 2004).…”

Phylogenetic position of the Neotropical Family Zonocotylidae (Paramphistomoidea) using partial 28S rDNA sequences

“…Pantoja et al . (2019), who focused solely on cladorchiids parasitizing Neotropical fishes, failed to confirm the monophyly of this family. Alves et al .…”

“…On the basis of the information available to date, the members of this well-supported clade share the geographical distribution (restricted to South America) and the association with freshwater hosts (fishes and mammals). Pantoja et al (2019), who focused solely on cladorchiids parasitizing Neotropical fishes, failed to confirm the monophyly of this family. Alves et al (2020) concurred with this assessment, highlighting the lack of statistical support for this clade.…”

“…Zonocotylidae consists of a single genus, Zonocotyle, with two species, Zonocotyle bicaecata Travassos, 1948 and Zonocotyle haroltravassosi (Padilha, 1978) Kohn, Fernandes, Macedo & Abramson, 1985(Kohn et al 2007). After the redescription by Padilha (1978), Lunaschi (1988) provided additional features mainly concerning the description of the tubular excretory vesicle and noted its similarity with those of Microrchis oligovitellum Lunaschi, 1987 and Doradamphistoma parauchenipteri (Lunaschi, 1989) Pantoja, Scholz, Luque, & Jones, 2019. According to Lunaschi (1988, the pars musculosa in the male terminal genitalia resembles those found in certain species of the Paramphistomidae and Gastrothylacidae families.…”

A Rare Fish Amphistome Revisited: The Phylogenetic Position of Kalitrema kalitrema (Trematoda: Cladorchiidae) Found in Hypostomus spp. (Siluriformes: Loricariidae) from Brazil

“…The group has greatly diversified in South America-in fact, most species are known from fish in this subcontinent-primarily in the two dominant groups of freshwater fishes, i.e., Characiformes and Siluriformes [9]. With the recent descriptions of new species by Pantoja et al [10,11], fish cladorchiids stand out as one of the most diverse groups of fish trematodes in South America, with 38 valid species [11,12]. Despite that, the knowledge of the actual diversity of these paramphistomes is largely underappreciated, a fact that is accentuated by the paucity of helminthological surveys in the literature, with less than 5% of the ichthyofauna of the region scrutinized for parasites [12].…”