Proharpoceras Chao: a new ammonoid lineage surviving the end-Permian mass extinction

Authors

  • ARNAUD BRAYARD,

  • HUGO BUCHER,

  • THOMAS BRÜHWILER,

  • THOMAS GALFETTI,

  • NICOLAS GOUDEMAND,

  • KUANG GUODUN,

  • GILLES ESCARGUEL,

  • JIM JENKS


Arnaud Brayard [arnaud.brayard@univ-lyon1.fr] and Gilles Escarguel [gilles.escarguel@univ-lyon1.fr], UMR 5125 PEPS CNRS, 69622 Villeurbanne Cedex, France; Université Lyon 1, Campus de la Doua, Bât. Géode, 69622 Villeurbanne Cedex, France; Hugo Bucher [hugo.fr.bucher@pim.unizh.ch], Thomas Brühwiler, [bruehwiler@pim.unizh.ch], Thomas Galfetti [galfetti@pim.unizh.ch] and Nicolas Goudemand [goudemand@pim.unizh.ch], Paläontologisches Institut und Museum der Universität Zürich, Karl-Schmid Strasse 4, CH-8006 Zürich, Switzerland; Kuang Guodun, Guangxi Bureau of Geology and Mineral Resources, Jiangzheng Road 1, Nanning, Guangxi 530023, China; Jim Jenks [jenksjimruby@comcast.net], 1134 Johnson Ridge Lane, West Jordan, Utah 84084, USA.

Abstract

Based on new, bed-rock controlled material from northwestern Guangxi and Oman, the Early Triassic genus Proharpoceras Chao is shown to be a representative of Otocerataceae. Character analysis excludes a direct link with the Griesbachian Otoceratidae and favours a derivation of Proharpoceras from the late Permian Anderssonoceratidae. The biostratigraphic range of Proharpoceras is restricted to the Smithian and its biogeographic distribution comprises Oman, South China, and Primorye, thus indicating an essentially low palaeolatitudinal distribution. Proharpoceras has no apparent relatives among other Early and Middle Triassic Ceratitida and is thus considered to be the last representative of Otocerataceae. This offshoot of the late Permian Anderssonoceratidae implies that an additional ammonoid lineage survived the end Permian extinction and that it dwindled away for some 2 Myr before going extinct.

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