A review of the genus Sclerocollum Schmidt & Paperna, 1978 (Acanthocephala: Cavisomidae) from rabbitfishes (Siganidae) in the Indian and Pacific Oceans

Seven of the eleven species of Siganus Richardson (Siganidae) collected off the coasts of Australia, New Caledonia, French Polynesia and Palau were infected with species of Sclerocollum Schmidt & Paperna, 1978 (Acanthocephala: Cavisomidae). A Principal Component Analysis (PCA) and a Discriminant Analysis were performed on a morphometric dataset of specimens of Sclerocollum including borrowed type-specimens of Sc. rubrimaris Schmidt & Paperna, 1978 from the Indian Ocean and of Sc. robustum Edmonds, 1964, the only acanthocephalan species known previously from an Australian siganid. These analyses showed that the lengths of proboscis hooks were useful variables for separating specimens into groups and supported the presence of two known species (Sc. robustum and Sc. rubrimaris) and one new species (Sc. australis n. sp.) in Australian waters. We found Sc. robustum in Siganus lineatus (Valenciennes) from off Queensland and Sc. rubrimaris in S. fuscescens (Houttuyn) from off Western Australia and Queensland, S. punctatissimus Fowler & Bean from off Queensland and S. argenteus (Quoy & Gaimard), S. corallinus (Valenciennes), S. canaliculatus (Park) and S. doliatus Guérin-Méneville from off New Caledonia (all new host and locality records) which we compared with museum specimens of Sc. rubrimaris from S. rivulatus Forsskål & Niebuhr and S. argenteus [as S. rostratus (Valenciennes)] from the Red Sea. The third species, Sclerocollum australis n. sp., was found only in S. corallinus and S. doliatus from off Queensland. Sclerocollum australis n. sp. can be distinguished from its congeners by a unique combination of characters of the proboscis armature, including lengths of hooks 1–7. Specimens of Sclerocollum were also found in Zebrasoma velifer (Bloch) (Acanthuridae) from off Queensland, and Coradion altivelis McCulloch (Chaetodontidae) and Heniochus acuminatus (Linnaeus) (Chaetodontidae) from off New Caledonia. No acanthocephalans were found in siganids collected from Palau (Micronesia) or Moorea (French Polynesia) or Moreton Bay and Noosa (Queensland, Australia). We found no acanthocephalans in S. puellus (Schlegel), S. punctatus (Schneider & Forster), S. spinus (Linnaeus) or S. vulpinus (Schlegel & Müller). Evidence suggests that species of the genus Sclerocollum have travelled with S. argenteus across the Indo-Pacific with Sc. rubrimaris dispersed widely and Sc. robustum and Sc. australis n. sp. restricted to the Queensland coast, Australia

A new classification for deep-sea opecoelid trematodes based on the phylogenetic position of some unusual taxa from shallow-water, herbivorous fishes off south-west Australia

We report on Scorpidotrema longistipes and two new species belonging to a new genus: Holsworthotrema enboubal ichthys gen. et sp. nov. and Holsworthotrema chaoderma sp. nov. These taxa are the first representatives of the subfamily Stenakrinae included in molecular phylogenetic analyses of the Opecoelidae. They resolve among the deep-sea + freshwater Plagioporinae (s.l.) clade, but exploit shallow-water marine fishes. Based on phylogeny, ecology and morphology, we reorganize this clade into four subfamilies: the Plagioporinae (s.s.) for freshwater taxa, the Stenakrinae as currently defined with the addition of Holsworthotrema, the Bathycreadiinae subf. nov. for Bathycreadium and the Podocotylinae, a resurrected concept, for Podocotyle, Bathypodocotyle gen. nov., Buticulotrema, Halosaurotrema gen. nov., Macrourimegatrema, Neolebouria and Tellervotrema. Bathypodocotyle is proposed for species from deep-sea fishes previously assigned to Allopodocotyle, and Halosaurotrema for Gaevskajatrema halosauropsi. Two deep-sea opecoelids represented by sequence data, Neolebouria lanceolata and Podocotyloides brevis, remain inadequately accommodated. These taxa are sister to the Stenakrinae and may require another new subfamily, but it is not yet clear which morphological and/or ecological characters would distinguish such a concept. Evidently, neither belongs to its nominal genus; we propose to accommodate these taxa in Mesobathylebouria gen. nov. and Abyssopedunculus gen. nov., respectively

Patterns of digenean parasitism of bivalves from the Great Barrier Reef and associated waters

Digenean parasites of marine bivalves are relatively poorly known, particularly in Australia. We surveyed 2256 bivalve individuals ( 47 species, 17 families) from Queensland marine waters incorporating south-east Queensland, Heron Island ( southern Great Barrier Reef) and Lizard Island ( northern Great Barrier Reef). Infections of trematode species from three families, Bucephalidae, Gorgoderidae and Monorchiidae, were found. Overall prevalence of infection was 2.3%. The Bucephalidae was the most commonly found family; 11 species were found in Tellinidae, Ostreidae, Isognomonidae and Spondylidae - the latter two previously unknown as hosts for bucephalids. A single gorgoderid infection was found in a venerid, Lioconcha castrensis. Five species of monorchiids were found from Tellinidae and Lucinidae. All infections are new host/parasite records. No infections were found in 35 of the 47 bivalve species sampled. The generally low prevalence of infection by digeneans of bivalves suggests that it is unlikely that any of the species reported here are seriously damaging to bivalve populations in these waters. We deduce that, at best, we have some life-cycle information but no actual identifications for 10% of the species of trematodes that infect bivalves of Queensland marine waters

Sanguinicola maritimus n. sp (Digenea : Sanguinicolidae) from Labridae (Teleostei : Perciformes) of southern Australian waters

A new species of Sanguinicola Plehn, 1905 is described from the marine teleosts Notolabrus parilus (Richardson) and N. tetricus (Richardson) (Perciformes: Labridae) from Western Australian and Tasmanian waters. This host distribution is strikingly anomalous; however, the present material fulfils the morphological criteria of Sanguinicola. S. maritimus n. sp. differs from previously described species in having the combination of a body 1,432-1,701 mu m long, the oesophagus 18.3-21.7% of the body length, the testis occupying 42.8-52.3% of the body length, an oviducal seminal receptacle and Mehlis' gland present, ovoid eggs, and vitelline follicles that extend anteriorly past the nerve commissure, laterally past the lateral nerve chords and posteriorly to the anterior margin of the cirrus-sac. S. maritimus also lacks a protrusible anterior proboscis. It also differs in the combination of host and geographical location, being the first Sanguinicola species from a marine teleost and the first from Australian waters