Oribatid mites (Acari: Oribatida) of sub-Antarctic Heard Island
Nine species of oribatid mites were represented in heat-extracted samples of soil and plant material and from pitfall trapping in the five main terrestrial plant communities on Heard Isl. Three species, Austroppia crozetensis (Richters, 1908), Globoppia loxolineata (Wallwork, 1965) and Halozetes marionensis Engelbrecht, 1974, are recorded from Heard Isl. for the first time. The zoogeographical relationships of the Heard Isl. oribatid mite fauna with those of other sub-Antarctic islands and Antarctic zones are discussed. It is concluded that the low taxonomic diversity (with zero endemism) is partly a reflection of the small ice-free area on Heard Isl., and that its depauperate fauna is transitional between those of the maritime and sub-Antarctic zones.