A complex of the blood fluke genus Psettarium (Digenea: Aporocotylidae) infecting tetraodontiform fishes of east Queensland waters

Abstract

Seven species of Psettarium (Digenea: Aporocotylidae), including four new species, are reported from tetraodontiform fishes from off coastal east Queensland. Psettarium pandora n. sp. infects the yellow boxfish, Ostracion cubicus (Ostraciidae), the first known aporocotylid to infect this family of fishes. Three new species are reported from pufferfishes of the genus Arothron (Tetraodontidae): Psettarium yoshidai n. sp. infects the map puffer (Arothron mappa), Psettarium hustoni n. sp. infects the black-spotted puffer (A. nigropunctatus) and Psettarium martini n. sp. infects the starry puffer (A. stellatus). We also report three species of Psettarium from Australian waters for the first time. Paracardicola hawaiensis Martin, 1960, the sole species of Paracardicola, is redescribed based on specimens collected from the type-host, the stars-and-stripes puffer, Arothron hispidus. Paracardicola is synonymised with Psettarium and P. hawaiensis is recombined as Psettarium hawaiiense (Martin, 1960) n. comb. Psettarium pulchellum Yong, Cutmore, Bray, Miller, Semarariana, Palm & Cribb, 2016, described from the narrow-lined puffer (Arothron manilensis) from off Bali, Indonesia, is reported from the same fish species at two locations on the Queensland coast, significantly extending the range of this species. Psettarium nolani (Bray, Cribb & Littlewood, 2013), originally described from French Polynesia, is reported from A. hispidus, A. manilensis and A. stellatus, representing both new host and locality records for this species. Molecular phylogenetic analysis shows these species to all be closely related, such that they cannot be considered to represent separate genera despite their differing morphology. Analysis of 28S sequence data for Psettarium anthicum Bullard & Overstreet, 2006, a non-tetraodontiform-infecting species, shows it to be distantly related to all other species of Psettarium for which sequence data are available. The species is re-assigned to a new genus, Cardallagium n. gen., as Cardallagium anthicum (Bullard & Overstreet, 2006) n. comb. We think it likely that the host range of species of Psettarium is limited to tetraodontiform fishes. We assessed the infection biology of two species, P. nolani and P. hawaiiense n. comb. infecting A. hispidus, using histology to assess the pathways of egg release for these species. Eggs of both species were observed in both circulatory and visceral organs of infected hosts, often in high numbers. Eggs were seen trapped in the mucosal layer of the intestine and, in rare instances, causing lesions in the laminar epithelium, providing the strongest evidence yet that they pass through the gut wall and escape the host via the faeces. Lastly, we discuss the biogeographical implications of our findings, noting that some Psettarium species now show very wide geographical distributions.

A new order of fishes as hosts of blood flukes (Aporocotylidae); description of a new genus and three new species infecting squirrelfishes (Holocentriformes, Holocentridae) on the Great Barrier Reef

“…This is strikingly different from the seemingly random distribution of eggs across the gills reported for species of other aporocotylid genera (e.g. [ 8 , 41 , 49 , 71 ]). We infer that gravid Holocentricola worms are highly mobile in the circulatory system and amass eggs in the reservoir, and, when laden, insert their posterior end into or enter a filament to lay.…”

“…Nolan et al [39] later described two Cardicola species from Lizard Island, one from each a lutjanid and a scombrid, and Nolan et al [40] described a new species of Phthinomita from an apogonid. As part of another PhD study, Yong et al [70][71][72] described three species of Cardicola, one from each of an apogonid, balistid and chanid, and two species of Psettarium Goto & Ozaki, 1930 from tetraodontiforms. Yong and Cribb [67] described a new genus and species from a tetraodontid, and Yong et al [68] surveyed butterflyfishes (Chaetodontidae) from the Great Barrier Reef, reporting Elaphrobates chaetodontis (Yamaguti, 1970) Yong, Cribb & Cutmore, 2021 from 19 chaetodontid species.…”

Lepocreadiidae Odhner, 1905 and Aephnidiogenidae Yamaguti, 1934 (Digenea: Lepocreadioidea) of fishes from Moreton Bay, Queensland, Australia, with the erection of a new family and genus

“…This phylogram includes the sequences used by Bray et al ( 2009 ) and Bray & Cribb ( 2012 ) in their reviews of the phylogeny and systematics of lepocreadioids and allows us to set the Moreton Bay worms in context. The uncontroversial results in the tree are the finding of identical sequences for Neomultitestis aspidogastriformis and Clavogalea trachinoti from off Heron Island and in Moreton Bay and the near identical sequences for Multitestis magnacetabulum from the same localities; species of several other trematode families have been shown to be genetically identical between the Great Barrier Reef and Moreton Bay (Brooks et al, 2017 ; Yong et al, 2018 ). More controversial is the close molecular similarity of Opechona austrobacillaris from Moreton Bay and O. kahawai from Tasmanian waters, which brings into question the status of these forms.…”

Revision of Sanguinicola Plehn, 1905 with Redescription of Sanguinicola volgensis (Rašín, 1929) McIntosh, 1934, Description of a New Species, Proposal of a New Genus, and Phylogenetic Analysis

“…inermis (218 bp) is similar to intergeneric sequence variability rather than interspecific variation. For example, sequences representing species of Psettarium Goto and Ozaki, 1930 and Cardallagium Yong, Cutmore, Jones, Gauthier, and Cribb, 2018 (formally assigned to Psettarium ) differ by 217 bp ( Warren et al, 2017a ; Yong et al, 2018 ).…”