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Enigmatic new mammals from the late Eocene of Egypt

Sánchez-Villagra, Marcelo ; Seiffert, Erik ; Martin, Thomas ; Simons, Elwyn ; Gunnell, Gregg ; Attia, Yousry

In: Paläontologische Zeitschrift, 2007, vol. 81, no. 4, p. 406-415

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    Titre
    • Enigmatic new mammals from the late Eocene of Egypt
    Auteur
    • Sánchez-Villagra, Marcelo. Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Straße 4, CH-8006, Zürich, Switzerland
    • Seiffert, Erik. Department of Anatomical Sciences, School of Medicine, Stony Brook University, 11794-8081, Stony Brook, New York, USA
    • Martin, Thomas. Institut für Paläontologie, Universität Bonn, Nussallee 8, D-53115, Bonn, Germany
    • Simons, Elwyn. Department of Biological Anthropology & Anatomy, Duke University, and Division of Fossil Primates, Duke Primate Center, 1013 Broad Street, 27705, Durham, North Carolina, USA
    • Gunnell, Gregg. Museum of Paleontology, Univeristy of Michigan, 48109-1079, Ann Arbor, MI, USA
    • Attia, Yousry. Egyptian Geological Museum, Misr el Kadima, Ethar el Nabi, Cairo, Egypt
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Paläontologische Zeitschrift, 2007, vol. 81, no. 4, p. 406-415. Springer-Verlag
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:317187
    Summary
    A new mammalian genus and species from the earliest late Eocene of Egypt is represented by a lower jaw fragment and two isolated lower molars. A rare combination of features and the fragmentary nature of the materials make their taxonomic assignment to either Marsupialia or Chiroptera uncertain. The holotype of the new genus is the best-preserved specimen in the sample, a dentary fragment with two molars that have uncompressed trigonids, weak buccal cingulids, and a nyctalodont arrangement of the hypocristid. Some traits appear to more clearly support marsupial, as opposed to chiropteran, affinities for this species, including the very likely presence of four molars in the dentary. The enamel of an additional lower molar assigned to this species consists of a single layer of radial enamel without any prism decussation, an enamel type that characterizes marsupials as well as chiropterans. A second taxon is represented by two isolated upper molars. Some traits appear to more clearly support marsupial, as opposed to chiropteran, affinities for these species, including the orientation of pre- and postprotocristae, the moderately slender lingual portion of the trigon, and the absence of any talon expansion. As some of these features can be found in various bat clades, chiropteran affinities for these species cannot be ruled out, but we propose that the new taxa are more likely to represent specialized ‘didelphimorphian' marsupials