New observations on Micropleura australiensis (Nematoda, Dracunculoidea), a parasite of crocodiles in Australia

Abstract

Scanning electron microscopy examination of male and female specimens of Micropleura australiensis Moravec, Kay et Hobbs, 2004 (Nematoda, Dracunculoidea) from the peritoneal cavity of the freshwater crocodile Crocodylus johnsoni of the Ord River in Western Australia revealed some previously unreported morphological features. The male, first studied by SEM, possesses the same number (14) of cephalic papillae as the gravid female, but these are comparatively larger and somewhat differently arranged; four slit-like depressions located near the inner base of male dorsolateral and ventrolateral cephalic papillae of the external circle are present. The inner margin of the female oral aperture is smooth, without papilla-like formations. The male caudal end is provided with a right-side ventral ala. The transverse cuticular striae on the male ventral surface bear minute ornamentations (rows of papilla-like formations) in the pre-and postcloacal region. For the first time, M. australiensis is reported from wild and farmed Crocodylus johnsoni and saltwater crocodile C. porosus (new host record) from four localities in the Northern Territory, Australia.