New Avian tracks from the lower to middle Eocene at Fossil Hill, King George Island, Antarctica

• Main Authors: Mansilla, Héctor, de Valais, Silvina, Stinnesbeck, Wolfgang, Varela, Natalia, Leppe, Marcelo
• Language: English
• Published: Cambridge University Press 2012
• Subjects: Ciencias Exactas y Naturales; Avian Footprints; Cenozoic; Gondwana; Ichnotaxonomy; Argentina; Fildes; Fildes peninsula; Fossil Hill; King George Island; Mansilla; Varela; Antarc*; Antarctic Science; Antarctica
• Online Access: http://rid.unrn.edu.ar/handle/20.500.12049/5872; https://hdl.handle.net/20.500.12049/5872; https://www.cambridge.org/core/journals/antarctic-science/article/new-avian-tracks-from-the-lower-to-middle-eocene-at-fossil-hill-king-george-island-antarctica/F40725074B84176E41129B758CBDE33A; https://doi.org/10.1017/S0954102012000260

Fil: Mansilla, Héctor. Instituto Antártico Chileno. Laboratorio de Palaeobiología; Chile. Fil: de Valais, Silvina. Universidad Nacional de Rio Negro. Instituto de Investigaciones en Paleobiologia y Geologia. Río Negro, Argentina. Fil: Stinnesbeck, Wolfgang. Universität Heidelberg. Institut für Geowissenschaften; Alemania. Fil: Varela, Natalia. Instituto Antártico Chileno. Laboratorio de Palaeobiología; Chile. Fil: Leppe, Marcelo. Instituto Antártico Chileno. Laboratorio de Palaeobiología; Chile. Trace fossils are long known to exist in the Fossil Hill Formation (lower to middle Eocene) at Fildes Peninsula, King George Island, Antarctica. During fieldwork in 2009, abundant new avian tracks were recovered, which are analysed here. Three avian ichnotaxa are distinguished. The most common impressions are tridactyls and tetradactyls with slender digit imprints II–IV and a posterior hallux. They are included in the ichnogenus Gruipeda. In addition tridactyl and tetradactyl footprints with short and thick digit impressions are conferred to Uhangrichnus. The third ichnotaxon is a tridactyl impression with broad and short digits assigned to Avipeda. The latter taxon is here documented for the first time from Antarctica. These avian tracks are preserved in volcaniclastic sediments consisting in reddish-brown layers of mudstone intercalated with coarse sandstone. The sequence represents lacustrine environments which seasonally dried and were episodically refilled. true -