A new ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula
M. Bond, M. A. Reguero, S. F. Vizcaíno, S. A. Marenssi, 2006. "A new ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula", Cretaceous–Tertiary High-Latitude Palaeoenvironments: James Ross Basin, Antarctica, J. E. Francis, D. Pirrie, J. A. Crame
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Notolophus arquinotiensis, a new genus and species of the family Sparnotheriodontidae (Mammalia, Litopterna), is represented by several isolated teeth from the shallow-marine sediments of the La Meseta Formation (late Early-Late Eocene) of Seymour Island, Antarctic Peninsula, which have also yielded the youngest known sudamericids and marsupials. The new taxon belongs to the extinct order of ‘South American native ungulate’ Litopterna characterized by the convergence of the later forms with the equids and camelids. Notolophus arquinotiensis shows closest relationships with Victorlemoinea from the Itaboraian (middle Palaeocene) of Brazil and Riochican-Vacan (late Palaeocene-early Eocene) of Patagonia, Argentina. Although still poorly documented, this new taxon shows that the early Palaeogene Antarctic faunas might provide key data concerning the problems of the origin, diversity and basal phylogeny of some of the ‘South American ungulates’ (Litopterna). This new taxon shows the importance of Antarctica in the early evolution of the ungulates and illustrates our poor state of knowledge.
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High-latitude settings are sensitive to climatically driven palaeoenvironmental change and the resultant biotic response. Climate change through the peak interval of Cretaceous warmth, Late Cretaceous cooling, onset and expansion of the Antarctic ice sheet, and subsequently the variability of Neogene glaciation, are all recorded within the sedimentary and volcanic successions exposed within the James Ross Basin, Antarctica. This site provides the longest onshore record of Cretaceous–Tertiary sedimentary and volcanic rocks in Antarctica and is a key reference section for Cretaceous–Tertiary global change. The sedimentary succession is richly fossiliferous, yielding diverse invertebrate, vertebrate and plant fossil assemblages, allowing the reconstruction of both terrestrial and marine systems. The papers within this volume provide an overview of recent advances in the understanding of palaeoenvironmental change spanning the mid-Cretaceous to the Neogene of the James Ross Basin and related biotic change, and will be of interest to many working on Cretaceous and Tertiary palaeoenvironmental change.