The Antarctic predatory mite Gamasellus racovitzai (Trouessart) (Mesostigmata) - A morphometric study of two subspecies

57 morphological characters were scored on a sample of 46 male and 55 characters on a sample of 40 female Gamasellus racovitzai, which had been collected from 10 localities in the maritime Antarctic. A lectotype of G. racovitzai, selected from the collection studied by TROUESSART, is designated. The same morphological characters have been scored for the lectotype and for the holotype of G. r. neo-orcadensis. Principal co-ordinates analysis indicates that there is a morphological separation between specimens of G. racovitzai from the South Orkney Islands and from elsewhere in the maritime Antarctic. Since LISTER (1984a) also found esterase differences, it is concluded that two subspecies of G. racovitzai should be recognised. The nominate subspecies is distributed along the Antarctic Peninsula, its offshore islands, and the South Shetland Islands, whilst subspecies neo-orcadensis is restricted to the South Orkney Island. G. r. neoorcadensis is redefined