THE MOSS MITES OF YES-TOR, DARTMOOR, DEVON (ACARI, ORIBATIDA) AND THEIR EVOLUTIONARY SIGNIFICANCE

A species list of oribatid mites collected from the summit of Yes Tor, Dartmoor, is given, together with notes on their distribution. Yes Tor lies south of latitude 51° in that part of Britain which remained ice free during the Pleistocene. The species found on Yes Tor are compared with the species recorded from the summits of 11 mountains lying north of latitude 53°, which were all ice‐covered at the period of maximum glaciation. In the case of Yes Tor and these 11 northern montane sites, three similar faunal elements have been identified arctic‐alpine species, European‐alpine species and a group of British montane species that are also common in the lowlands. The view is advanced that the similarity of the montane oribatid fauna of Yes Tor with that of the mountains to the north of latitude 53° has resulted from the probable movements of the mites during Quaternary and postglacial times over an area extending from the Arctic Circle to the Mediterranean. It is suggested that these movements, while being largely spontaneous, have also been aided by transportation agents, both physical and biological. Copyright © 1992, Wiley Blackwell. All rights reserved