Publications by authors named "Richard D Corner"

2 Publications

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Gastropod first intermediate hosts for two species of Monorchiidae Odhner, 1911 (Trematoda): I can't believe it's not bivalves!

Int J Parasitol 2021 Jun 27. Epub 2021 Jun 27.

The University of Queensland, School of Biological Sciences, St Lucia, QLD 4072, Australia.

The trematode superfamily Monorchioidea comprises three families of teleost parasites: the Monorchiidae Odhner, 1911, Lissorchiidae Magath, 1917, and Deropristidae Cable & Hunninen, 1942. All presently known lissorchiid and deropristid life cycles have gastropods as first intermediate hosts, whereas those of monorchiids involve bivalves. Here, we report an unexpected intermediate host for monorchiids; two species of Hurleytrematoides Yamaguti, 1954 use gastropods as first intermediate hosts. Sporocysts and cercariae were found infecting two species of the family Vermetidae, highly specialised sessile gastropods that form calcareous tubes, from two locations off the coast of Queensland, Australia. These intramolluscan infections broadly corresponded morphologically to those of known monorchiids in that the cercariae have a spinous tegument, oral and ventral suckers, a simple tail and distinct eye-spots. Given the simplified morphology of intramolluscan infections, genetic data provided a definitive identification. ITS2 rDNA and cox1 mtDNA sequence data from the gastropod infections were identical to two species of Hurleytrematoides, parasites of butterflyfishes (Chaetodontidae); Hurleytrematoides loi McNamara & Cribb, 2011 from Moreton Bay (south-eastern Queensland) and Heron Island (southern Great Barrier Reef) and Hurleytrematoides morandi McNamara & Cribb, 2011 from Heron Island. Notably, species of Hurleytrematoides are positioned relatively basal in the phylogeny of the Monorchiidae and are a sister lineage to that of species known to infect bivalves. Thus, the most parsimonious evolutionary hypothesis to explain infection of gastropods by these monorchiids is that basal monorchiids (in our analyses, species of Cableia Sogandares-Bernal, 1959, Helicometroides Yamaguti, 1934 and Hurleytrematoides) will all prove to infect gastropods, suggesting a single host switching event into bivalves for more derived monorchiids (17 other genera in our phylogenetic analyses). A less parsimonious hypothesis is that the infection of vermetids will prove to be restricted to species of Hurleytrematoides, as an isolated secondary recolonisation of gastropods from a bivalve-infecting lineage. Regardless of how their use arose, vermetids represent a dramatic host jump relative to the rest of the Monorchiidae, one potentially enabled by their specialised feeding biology.
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June 2021

A new genus of Bucephalidae Poche, 1907 (Trematoda: Digenea) for three new species infecting the yellowtail pike, Sphyraena obtusata Cuvier (Sphyraenidae), from Moreton Bay, Queensland, Australia.

Syst Parasitol 2020 10 13;97(5):455-476. Epub 2020 Aug 13.

School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia.

Three new species of the family Bucephalidae Poche, 1907 (Trematoda: Digenea) are described from the yellowtail pike, Sphyraena obtusata Cuvier (Sphyraenidae), from Moreton Bay, Queensland, Australia. The three species are morphologically consistent with the present broad concept of the genus Bucephalus Baer, 1827, but significant phylogenetic and ecological differences relative to the type-species of Bucephalus require the proposal of a new genus. Aenigmatrema n. g. is proposed for A. undecimtentaculatum n. sp. (type-species), A. inopinatum n. sp. and A. grandiovum n. sp. In addition, based on morphological, ecological and biogeographical similarities, we recombine two existing species of Bucephalus as Aenigmatrema kaku (Yamaguti, 1970) n. comb. and Aenigmatrema sphyraenae (Yamaguti, 1952) n. comb. Although the three species described in this study are extremely morphologically similar, they can be differentiated from each other, and from A. kaku and A. sphyraenae, morphometrically on the basis of egg size, tentacle number and a combination of the caecum and vitelline field lengths. Complete ITS2 rDNA, partial 28S rDNA and partial cox1 mtDNA sequence data were generated for the three new species, which formed a well-supported clade in all 28S phylogenetic analyses. An expanded phylogenetic tree for the subfamily Bucephalinae Poche, 1907 is presented, demonstrating unresolved issues with the morphology-based taxonomy of the subfamily. The three largest genera, Bucephalus, Rhipidocotyle Diesing, 1858 and Prosorhynchoides Dollfus, 1929 remain extensively polyphyletic, indicating the need for significant further systematic revision.
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October 2020