Systematics and Biology of a New Dracuncoloid Nematode and New Opistholebetid Trematodes in Tetraodontiform Fish

The systematics and some aspects on the biology of a dracunculoid nematode and opistholebetid trematodes parasitic in tetraodontiforms are presented. Moravecia australiensis Ribu and Lester 2004, a new dracunculoid genus and species, is described from gill filaments of the green porcupine fish Tragulichthys jaculiferus (Cuvier) (Tetraodontiformes: Diodontidae) in Moreton Bay. The absence of a buccal capsule, a divided oesophagus, a functional vulva and a single ovary in females and the presence of caudal alae and spicules in males, are typical characters of the Guyanemidae. This family has four known genera; Guyanema and Travassosnema are exclusively parasites of freshwater fish in South America, Pseudodelphis is a parasite of the tidepool sculpin in Canada and perciform fish in Argentina, and Histodytes in the elasmobranch Raja microocellata off the European Atlantic Coast. Existing species are parasitic in the body cavity except for T. travassosi parasitic in the eye, H. microocellatus in various tissues including gills and P. limnicola in the heart. The new genus differs from these genera by its fine cuticular transverse striations, two forward protruding cephalic elevations, a small mouth surrounded by 6 cephalic papillae arranged in two lateral clusters of three each and a pair of large lateral amphids. The males have only two pairs of pedunculated caudal papillae supporting the caudal alae. A key to the genera of the Family Guyanemidae is presented