Antarctomithrax thomsoni, a new genus and species of crab (Brachyura; Majidae) from the La Meseta Formation (Eocene) of Seymour Island, Antarctica

• Published in: Journal of Paleontology
• Main Author: Feldmann, Rodney M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1994
• Subjects: Paleontology; Antarctic; The Antarctic; Antarctic Peninsula; Seymour; Seymour Island; Elliot; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1017/s0022336000025725; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000025725

The james ross basin, situated on the eastern margin of the Antarctic Peninsula, has yielded an extensive fauna of decapod crustaceans spanning Late Cretaceous through Eocene time. To date, 28 species in 22 genera and 18 families have been described (Feldmann, 1992; Feldmann, Tshudy, and Thomson, 1993), making this the most diverse fossil decapod fauna in the Southern Hemisphere. Within the basin, Seymour Island alone contains rocks of the Eocene age La Meseta Formation from which seven species of crabs, one galatheid, and one species of callianassid ghost shrimp have been described (Feldmann and Zinsmeister, 1984; Feldmann and Wilson, 1988; Feldmann, 1992). The fauna of the La Meseta is remarkable also because, although the organisms are preserved in rocks deposited in moderate- to high-energy, shallow-water habitats (Elliot and Trautman, 1982), many of the species represent early occurrences of taxa with living descendants that are characteristic of deeper water, lower latitude habitats (Zinsmeister and Feldmann, 1984).