title: Antarctotrechus ballisp. n. (Carabidae, Trechini): the first ground beetle from Antarctica.
abstract: Fossil elytra of a small trechine carabid are reported from the Oliver Bluffs on the Beardmore Glacier at lat. 85°S. They were compared with counterparts from the extant generaTrechisibus,Tasmanorites,OxytrechusandPseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new speciesAntarctotrechus balliin honour of George E. Ball who made major contributions to the study of carabids through his own research and the training of students while at the University of Alberta, Edmonton, Alberta, Canada. The closest extant relatives to the extinctAntarctotrechus balliare species ofTrechisibus, which inhabit South America, the Falkland Islands and South Georgia, andTasmanorites, which inhabit Tasmania, Australia. Plant fossils associated withAntarctotrechus balliincludedNothofagus(southern beech),Ranunculus(buttercup), moss mats and cushion plants that were part of a tundra biome. Collectively, the stratigraphic relationships and the growth characteristics of the fossil plants indicate thatAntarctotrechus balliinhabited the sparsely-vegetated banks of a stream that was part of an outwash plain at the head of a fjord in the Transantarctic Mountains. Other insects represented by fossils in the tundra biome include a listroderine weevil and a cyclorrhaphan fly. The age of the fossils, based on comparison of associated pollen with40Ar/39Ar dated pollen assemblages from the McMurdo Dry Valleys, is probably Early to Mid-Miocene in the range 14-20 Ma. The tundra biome, includingAntarctotrechus balli, became extinct in the interior of Antarctica about 14 Ma and on the margins of the continent by 10-13 Ma.Antarctotrechus balliconfirms that trechines were once widely distributed in Gondwana. ForAntarctotrechus balliand other elements of the tundra biome it appears they continued to inhabit a warmer Antarctica for many millions of years after rifting of Tasmania (45 Ma) and southern South America (31 Ma).
authors.affiliation: Quaternary Entomology Lab, Department of Geosciences, North Dakota State University, Fargo, North Dakota 58108, USA.
authors.forename: Allan C
authors.initials: AC
authors.lastname: Ashworth
authors.affiliation: Hyper-diversity Group, Department of Entomology, MRC-187, National Museum of Natural History, Smithsonian Institution, Washington, P.O. Box 37012, DC 20013-7012, USA.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Erwin
keywords: Antarctica; Carabidae; Miocene; Trechini