Inference of phylogeny and taxonomy within the Didymozoidae (Digenea) from the second internal transcribed spacer (ITS2) of ribosomal DNA

DNA sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) were determined for 11 species from four genera of Didymozoinae (Indodidymozoon, Helicodidymozoon, Rhopalotrema and Neometadidymozoon) and a species of the Lecithasteridae, Lecithaster stellatus. Sequences were used to test the validity of species recognised on morphological criteria and to infer phylogenetic relationships. Sequences of the 11 didymozoids differed by 0.5% to 19%. Our phylogenetic analyses: (i) indicate that species in the genera Helicodidymozoon and Rhopalotrema are a monophyletic group; (ii) support separation of the genus Helicodidymozoon from the genera Indodidymozoon and Neometadidymozoon; and (iii) support recognition of Rhopalotrema as a genus distinct from Neometadidymozoon. We found the gonochoristic species, I. pearsoni and I. suttiei, to be genetically similar to the hermaphroditic species in the genus Indodidymozoon and found no evidence to indicate that they belong in a separate genus.

The Australian species of Lobatocreadium Madhavi, 1972, Hypocreadium Ozaki, 1936 and Dermadena Manter, 1945 (Digenea: Lepocreadiidae), parasites of marine tetraodontiform fishes

The genera Lobatocreadium, Pseudocreadium, Hypocreadium and Dermadena are redefined and host lists given. Provisional keys to species of Lobatocreadium, Hypocreadium and Dermadena are presented. The following species are described from (1) the Great Barrier Reef: Lobatocreadium exiguum from Balistapus undulatus and Sufflamen bursa; Hypocreadium cavum n. sp. from Abalistes stellatus (type-host) and Cantheschenia grandisquamis; H. grandisquamis n. sp. from Cantheschenia grandisquamis; Dermadena spatiosa n. sp, from Cantheschenia grandisquamis; and (2) southwestern Australia: D. stirlingi n. sp. from Meeschenia hippocrepis. The following new combinations are made: Lobatocreadium vitellosum (Ozaki, 1936) n. comb. (originally Leptocreadium); Hypocrendium balistes (Nagaty, 1942) n. comb. (originally Pseudocreadium); H. biminensis (Sogandares-Bernal, 1959) n. comb. (originally Pseudocreadium); H. indicum (Madhavi, 1972) n. comb. (originally Pseudocreadium); and H. galapagoensis (Manter, 1945) n. comb. (originally Pseudocreadium). Several nominal species of Pseudocreadium and Hypocreadium are considered incertae sedis.

Lepocreadiinae lepocreadiids (Digenea) from tetraodontiform fishes in the waters off Tasmania, Queensland and Moorea, French Polynesia

Two new species of Pseudocreadium are described from off northern Tasmania, P maturini sp. nov. from Meuschenia freycineti and P aubreyi sp. nov. from Acanthaluteres vittiger. They differ from the only other recognised species in the genus by the number of ovarian lobes and by size, and they differ from each other by size, shape, caecal length, forebody length, pre-oral lobe size, uterine position, excretory vesicle length and oral sucker shape. Lobatocreadium exiguum is redescribed from Sufflamen bursa, off Moorea, French Polynesia and Abalistes stellatus, Swain Reefs, Great Barrier Reef, Queensland. Records and measurements are given for Hypocreadium cavum from Sufflamen fraenatus and Lepotrema clavatum from Melichthys vidua, both off Heron Island, Great Barrier Reef, Queensland.