Tardigrades of the Australian Antarctic: A new species of the marine genusEchiniscoides from Macquarie Island, Subantarctica

A new species of marine heterotardigrade, Echinisoides horningi sp. n. is d escribed from samples collected during the 1977-78 Australian Museum Expedi tion to Sub-Antarctic Macquarie Island. The genus Echiniscoides is usually found in littoral habitats and associated with the algae Enteromorpha or on barnacles covered with algae. Recently new records have extended the distr ibution of Echiniscoides, and the genus is found also subtidal in the sandy detritus covered with green algae or in the calcareous tubes of polychaete s. This new species was collected from a sample of the lichen Caloplaca sp. in the supralittoral zone, a more terrestrial habitat than other members o f the genus, except for one dubious record from a soil sample at an altitud e of 1000 m above sea level in the former Belgian Congo. The lichens on Mac quarie Island were exposed to heavy sea spray and may be the ingredients th at foster this unique colonization of a Subantarctic terrestrial habitat.