Published November 23, 2016 | Version v1
Journal article Open

Antarctotrechus balli sp. n. (Carabidae, Trechini): the first ground beetle from Antarctica

  • 1. Geosciences, North Dakota State University
  • 2. National Museum of Natural History, Smithsonian Institution, Washington

Description

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 genera Trechisibus, Tasmanorites, Oxytrechus and Pseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new species Antarctotrechus balli in 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 extinct A. balli are species of Trechisibus, which inhabit South America, the Falkland Islands and South Georgia, and Tasmanorites, which inhabit Tasmania, Australia. Plant fossils associated with A. balli included Nothofagus (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 that A. balli inhabited 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 with 40Ar/39Ar dated pollen assemblages from the McMurdo Dry Valleys, is probably Early to Mid-Miocene in the range 14–20 Ma. The tundra biome, including A. balli, became extinct in the interior of Antarctica about 14 Ma and on the margins of the continent by 10–13 Ma. A. balli confirms that trechines were once widely distributed in Gondwana. For A. balli and 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).

Files

ZK_article_10535.pdf

Files (7.4 MB)

Name Size Download all
md5:ee8449fa3fa2150d14ce3b358a0c5f08
7.3 MB Preview Download
md5:c83c2a2ad1a77e6e884a0f8544003afe
77.6 kB Preview Download

Linked records