Expansion of the concept of the Opistholebetinae Fukui, 1929 (Digenea: Opecoelidae Ozaki, 1925), with Magnaosimum brooksae n. g., n. sp. from Tripodichthys angustifrons (Hollard) (Tetraodontiformes: Triacanthidae) in Moreton Bay, Australia

Abstract

The Opecoelidae Ozaki, 1925, the largest trematode family, currently lacks an adequate subfamilial organisation. In particular, recent analyses have shown that the sequenced representatives of the Opistholebetinae Fukui, 1929 are nested among taxa currently recognised in the Plagioporinae Manter, 1947, which itself is polyphyletic. The concept of the Opistholebetinae persists because its 25 or so species are united by a distinctive morphology and a narrow host range; species are known only from tetraodontiform fishes, specifically of the Tetraodontidae and Diodontidae, and possess a muscular post-oral ring, unusual pigmented granules throughout the body and a ventral sucker positioned more posteriorly than is typical for other opecoelids. Here we report on Magnaosimum brooksae n. g., n. sp. from a tetraodontiform, Tripodichthys angustifrons (Hollard) (Triacanthidae), collected in Moreton Bay, Australia. The new species has a longer forebody than hindbody, but lacks a post-oral ring and pigmented granules. It resolves to the plagioporine clade containing the Opistholebetinae, but does not form a monophyletic grouping with those taxa. We propose to expand the concept of the Opistholebetinae to include Magnaosimum, as well as Gaevskajatrema Gibson & Bray, 1982, Macvicaria Gibson & Bray, 1982, Pachycreadium Manter, 1954, Peracreadium Nicoll, 1909, Pinguitrema Siddiqi & Cable, 1960, Propycnadenoides Fishcthal & Kuntz, 1964, Pseudopycnadena Saad-Fares & Maillard, 1986, Pycnadena Linton, 1911 and Pycnadenoides Yamaguti, 1938.

The Pseudoplagioporinae, a new subfamily in the Opecoelidae Ozaki, 1925 (Trematoda) for a small clade parasitizing mainly lethrinid fishes, with three new species

“…Within the large marine clade, the Pseudoplagioporinae resolved as sister to clade C. Its concept could therefore be extended to include those taxa, specifically, the genera Choerodonicola Cribb, 2005 and Trilobovarium Martin, Cutmore, and Cribb, , but probably not Podocotyloides Yamaguti, or Macvicaria Gibson & Bray, because neither Podocotyloides parupenei (Manter, 1963) Pritchard, 1966 nor the four species of Macvicaria resolving to clade C in the analyses are likely to prove genuine representatives of these genera, which probably belong to clade B and the Opistholebetinae, respectively (see Martin, Crouch, et al., ; Martin, Cutmore, et al., ). However, there is no morphological or ecological basis to unite the pseudoplagioporine taxa with those of clade C and the two are separated by considerable phylogenetic distance comparable to differences between other opecoelid subfamilies.…”

“…However, most taxa which have been considered to belong to the Plagioporinae are marine. Already, many have been accommodated into new subfamily concepts, the Bathycreadiinae Martin, Huston, Cutmore, & Cribb, , Helicometrinae Bray, Cribb, Littlewood, & Waeschenbach, Opistholebetinae Fukui, 1929, Podocotylinae Dollfus, 1959, and Polypipapiliotrematinae Martin, Cutmore, & Cribb, , based on a combination of adult morphology, host usage, and phylogenetic distinctions (Bray et al., ; Martin, Crouch, Cutmore, & Cribb, ; Martin, Sasal, Cutmore, Ward, Aeby, & Cribb, ; Martin et al., ). Thus, the Opecoelidae is currently divided into nine subfamilies, although two sizeable clades of marine taxa (see Martin et al., ) remain without suitable subfamilial designation and the placement of multiple genera not yet represented by sequence data remains uncertain.…”

Intermediate host switches drive diversification among the largest trematode family: evidence from the Polypipapiliotrematinae n. subf. (Opecoelidae), parasites transmitted to butterflyfishes via predation of coral polyps

“…Cribb, 1985Jousson and Bartoli, 2000;Yoshida and Urabe, 2005), potentially the deep-sea taxa (Thompson and Margolis, 1987;Blend and Dronen, 2015b), and some (Schell, 1975;Hendrix, 1978), but not all (Sinitsin, 1931;Schell, 1976;Yano and Urabe, 2017) freshwater plagioporines (sensu stricto). In contrast, only opistholebetines are known to use gastropod and echinoid second intermediate hosts (Martin et al, 2018b) and the few life-cycles known from the major lineage referred to as the 'Plagioporinae (sensu lato) clade B' exploit fishes as second intermediate hosts (McCoy, 1929(McCoy, , 1930; Downie, A.…”

Records of opecoeline species Pseudopecoelus cf. vulgaris and Anomalotrema koiae Gibson & Bray, 1984 (Trematoda, Opecoelidae, Opecoelinae) from fish of the North Pacific, with notes on the phylogeny of the family Opecoelidae

“…Based on the estimates using Tracer, 250,000 generations were discarded for burn-in (the relative burn-in parameter was switched off). The names of the clades are given following Martin et al (2018b, c).…”

“…The family Opecoelidae Ozaki, 1925 is a large group of trematodes parasitic in marine and freshwater fish. The modern taxonomic model of this family, based on morphological (Cribb, 2005; Bakhoum et al , 2017) and genetic data (Bray et al , 2016; Martin et al , 2018b, c), distributes opecoelids between six subfamilies: Opecoelinae, Helicometrinae, Opecoelininae, Opistholebetinae, Stenakrinae and Plagioporinae s. lato . Plagioporinae s. lato is the most problematic group of opecoelids from the taxonomic point of view, as phylogenetic reconstructions demonstrate the polyphyly of this subfamily (Andres et al , 2014; Shedko et al ., 2015; Bray et al , 2016; Fayton and Andres, 2016; Faltýnková et al , 2017; Fayton et al ., 2017; Martin et al , 2017, 2018b; Rima et al , 2017; Fayton et al , 2018).…”