Australiformis.
Australiformis is a monotypic genus of acanthocephalans (thorny-headed or spiny-headed parasitic worms) that infest marsupials in Australia and New Guinea. The worm's body consists of a long trunk and a proboscis armed with hooks which it uses to pierce and hold the gut wall of its host. Its only species, Australiformis semoni, resembles species in the genus Moniliformis but lacks spiral muscles in the outer wall of the proboscis receptacle. The proboscis is armed with 12 rows of 13 to 15 hooks which are used to attach themselves to the small or large intestine of the host. The female worms range from 95 to 197 mm long, virtually all of which is the trunk, and 1.75 to 3.5 mm wide. There is pronounced sexual dimorphism in this species as females are around twice the size of the males, whose trunks range from 46 to 80 mm long and are about 2 mm wide. Infestation of marsupials by A. semoni may cause debilitating inflammation of the stomach (gastritis) with granulomatous ulcers.
