Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2010 Fossil xenarthran mammals from Venezuela - taxonomy, patterns of evolution and associated faunas Carlini, A A Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-58039 Dissertation Published Version Originally published at: Carlini, A A. Fossil xenarthran mammals from Venezuela - taxonomy, patterns of evolution and associated faunas. 2010, University of Zurich, Faculty of Science. FOSSIL XENARTHRAN MAMMALS FROM VENEZUELA – TAXONOMY, PATTERNS OF EVOLUTION AND ASSOCIATED FAUNAS Dissertation zur Erlangung der naturwissenschaftlichen Doktorwürde (Dr. sc. nat.) vorgelegt der Mathematisch-naturwissenschaftlichen Fakultät der Universität Zürich von Alfredo A. Carlini aus Argentinien Promotionskomitee Prof. Dr. Marcelo Sánchez (Leiter der Dissertation, Vertreter der Universität Zürich) PD Dr. Winand Brinkmann Dr. Richard H. Madden Prof. Dr. Lukas Keller Zürich, 2010 ALFREDO A. CARLINI FOSSIL XENARTHRAN MAMMALS FROM VENEZUELA Zusammenfassung der Dissertation für nichtakademisches Laienpublikum Basierend auf Analysen neuer Fossilfunde werden in der vorliegenden Studie neue Erkenntnisse zur Evolution der Xenarthra des tropischen Südamerikas vorgestellt. Die Vielfalt der Säugetierformen der letzten 10 Millionen Jahre in Venezuela ist ein Schlüssel zum Verständnis der Faunenbewegungen zwischen Süd-, Mittel- und Nordamerika sowie den karibischen Inseln. Es wurden Vertreter zweier Taxa der Xenarthra untersucht: Faultiere, sowie der durch körperbedeckende „Panzer“ charakterisierten Gürteltiere und Glyptodonten. Einige der neu beschriebenen Fossilien repräsentieren neue Stammeslinien und es wurden neuer Gattungen sowie Arten gefunden, welche aus dem südlichen Südamerika unbekannt sind. Der erste Nachweis des Glyptodonten Glyptotherium innerhalb Südamerikas ist ein Indiz für das Vorhandensein von eiszeitlichen „Korridoren“ durch den amerikanischen Kontinent. Abstract for non-academic audience This work presents new discoveries and analyses of fossils documenting the evolution of the Xenarthra mammals in the tropical regions of South America. The mammalian diversity of the last 10 million years in the area north of the Orinoco River in Venezuela, is a key area to understand the faunal exchanges with Central and North America and with the Caribbean Islands. Representatives of two clades were investigated: the sloths, and the armadillos and glyptodonts, characterized by having their body covered by an “armour” shell. Some of the new fossils are representatives of new lineages and are described as new genera and species unknown from southern South America. The first documentation for South America of the glyptodont Glyptotherium suggests the presence of “corridors” across the American continent formed during the maximum glacial periods. CONTENTS ABSTRACT……………………………………………………………………............…p. 7 ZUSAMMENFASSUNG…...……………………………………………………....….....…p. 9 FOREWORD…………………………………………………………..………..……..…p. 11 CHAPTER 1 Book chapter submitted to Tejedor M. & Rosenberger A. Origins and Evolution of Cenozoic South American Mammals, Springer Verlag (Carlini AA, Sánchez-Villagra MR) Fossil mammals from the Venezuelan Neogene and the significance of the intertropical record. The Urumaco sequence……………………..……….………p. 17 CHAPTER 2 Book chapter in press in Urumaco and Venezuelan Palaeontology – The fossil record of the Northern Neotropics, Indiana University Press, edited by Sánchez-Villagra MR, Aguilera O, Carlini AA, eds (Carlini and Zurita) An Introduction to Cingulate Evolution and their evolutionary history during the Great American Biotic Interchange: Biogeographical clues from Venezuela………………………………………………………………….....….……p. 49 CHAPTER 3 Article published in Palaeontologische Zeitschrift (Carlini et al. 2008, Vol. 82/2, pp. 139-152) New Glyptodont from Codore Formation (Pliocene), Falcón State, Venezuela, its relationship with the Asterostemma problem and the palaeobiogeography of the Glyptodontinae……………………………………...……………………………...…p. 73 CHAPTER 4 Article published in Palaeontologische Zeitschrift (Carlini et al. 2008, Vol. 82/2, pp. 125-138) North American Glyptodontines (Xenarthra, Mammalia) in the Upper Pleistocene of northern South America………………………………………………………………p. 87 CHAPTER 5 Article published in Palaeontologische Zeitschrift (Carlini et al. 2008, Vol. 82/2, pp. 153-162) Additions to the knowledge of Urumaquia robusta (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco Formation (Late Miocene), Estado Falcón, Venezuela……………………………………………………………….…………p. 101 CHAPTER 6 Future perspectives………………………………………………..…p. 111 APPENDIX………………………………………………………………………….….p. 115 Book chapter in press in Urumaco and Venezuelan Palaeontology – The fossil record of the Northern Neotropics, Indiana University Press (Sánchez-Villagra MR, Aguilera O, Carlini AA, eds) The fossil vertebrate record of Venezuela of the last 65 million years……..…p. 117 Article published in Acta Zoologica (Krmpotic et al. 2009, Vol. 90/4, pp. 339-351) Krmpotic CM, Ciancio MR, Barbeito C, Mario RC, Carlini AA. 2009. Osteoderm morphology in recent and fossil euphractine xenarthrans. ………………..…...p. 151 Article published in Mammalian Biology (Galliari et al. 2010, doi:10.1016/j.mambio.2009.03.014) Galliari FC, Carlini AC, Sánchez-Villagra MR. 2010. Evolution of the axial skeleton in armadillos (Mammalia, Dasypodidae)…………………………..…..……….…p. 165 ACKNOWLEDGEMENTS……………………………..…………………………....……p. 173 CURRICULUM VITAE……………………………...……………………...……………p. 175 ALFREDO A. CARLINI FOSSIL XENARTHRAN MAMMALS FROM VENEZUELA Abstract This work presents new discoveries and analyses of fossils documenting much new about the taxonomy and biogeography of Xenarthra, a diverse group of mostly South American distribution. These studies serve to address major issues about the origin and evolution of mammals in the intertropics. Some extensive areas with sedimentary rocks north of the Orinoco River, at the northern extreme of South America, provide a first glimpse into a mammalian diversity from the Neogene unrecorded in other areas of the continent. Some discoveries are being used to document the importance of northern South America as ʻcradle and museumʼ for many clades, and as the key area to understand the nature of the exchanges with Central and North America during the Great American Biotic Interchange and the faunal exchange with the Caribbean Islands during the Cenozoic. Representatives of two main clades of xenarthrans were investigated: the Tardigrada, commonly known as sloths and ground sloths, and the Cingulata, including the armadillos, pampatheres and glyptodonts, characterized by having their body covered by an “armour” shell formed by articulated and joined osteoderms. A new genus of glyptodont is erected, Boreostemma, which serves as example of the distinctive nature of the northern South American xenarthran diversity in contrast to the Argentinian one. The Colombian and Venezuelan species of this genus had been previously allocated in a taxon of widespread distribution, but new fossils and a consideration of the anatomy and phylogenetic significance of known materials suggests the existence of a distinct intertropical genus. Anatomical comparisons leading to phylogenetic conclusions in a temporal framework, suggest that the Glyptodontinae arose in the northernmost regions of South America and their arrival to more southerly areas coincided with the desertification in lower latitudes of South America, maybe by an open landscape corridor close to the andean area (in the late Miocene-Pliocene interval). 7 ALFREDO A. CARLINI FOSSIL XENARTHRAN MAMMALS FROM VENEZUELA The presence of Glyptotherium is documented in the latest Pleistocene (ca. 14 ka) of Venezuela. The discovery of an otherwise North and Central American genus is of great biogeographical significance, as it suggests the presence of “corridors” that could have formed during the maximum of glacial periods. A similar bidirectional migratory pattern has been proposed for another Cingulata group, the pampatheriids, as well as for a megatherin genus. Because of taphonomical bias, most Tardigrada taxa treated here are represented by long bones, most frequently femora, and consequently, much new anatomical reference work was needed, as most xenarthran fossil and living taxa have been traditionally diagnosed based on other features of the anatomy. The tardigrade diversity recorded in the Neogene of Venezuela is surprisingly large and comparable to that reached only a few times during their history, including the Late Oligocene of Patagonia, Middle Miocene of Patagonia and Late Miocene of northeastern Argentina. New remains of several postcranial bones of the tardigrade Urumaquia robusta are described, significantly improving the knowledge of the species and its relations to other Megatheriinae, in particular with Pyramiodontherium and Megatheriops. The Venezuelan xenarthran fossil localities contain a rich diversity and include very basal tardigrade taxa, the earliest representatives of new lineages, as well as clades not known from the extensively prospected sites of southern South America. Key Words: South America, Postcranial Anatomy, Biogeography, Great American Biotic Interchange, Miocene, Pliocene, Pleistocene 8 ALFREDO A. CARLINI FOSSIL XENARTHRAN MAMMALS FROM VENEZUELA Zusammenfassung Basierend auf Analysen neuer Fossilfunde werden in der vorliegenden Studie neue Erkenntnisse