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Anatomy and evolution of the first Coleoidea in the Carboniferous.

  • Klug C 1Paläontologisches Institut und Museum, Universität Zürich, Karl-Schmid-Strasse 4, 8006 Zürich, Switzerland.
  • Landman NH 2Division of Paleontology (Invertebrates), American Museum of Natural History, 79th Street and Central Park West, New York, NY 10024 USA.
  • Fuchs D 3SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße. 10, 80333 Munich, Germany.
  • Mapes RH 2Division of Paleontology (Invertebrates), American Museum of Natural History, 79th Street and Central Park West, New York, NY 10024 USA.
  • Pohle A 1Paläontologisches Institut und Museum, Universität Zürich, Karl-Schmid-Strasse 4, 8006 Zürich, Switzerland.
  • Guériau P 4IPANEMA, CNRS, Ministère de la Culture, UVSQ, USR3461, Université Paris-Saclay, 91192 Gif-sur-Yvette, France.
  • Reguer S 5Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France.
  • Hoffmann R 6Institute of Geology, Mineralogy, & Geophysics, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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  • 2019-08-03
Published in:
  • Communications biology. - 2019
Palaeontology
Zoology
Animals
Biological Evolution
Fossils
Mollusca
Phylogeny
English Coleoidea (squids and octopuses) comprise all crown group cephalopods except the Nautilida. Coleoids are characterized by internal shell (endocochleate), ink sac and arm hooks, while nautilids lack an ink sac, arm hooks, suckers, and have an external conch (ectocochleate). Differentiating between straight conical conchs (orthocones) of Palaeozoic Coleoidea and other ectocochleates is only possible when rostrum (shell covering the chambered phragmocone) and body chamber are preserved. Here, we provide information on how this internalization might have evolved. We re-examined one of the oldest coleoids, Gordoniconus beargulchensis from the Early Carboniferous of the Bear Gulch Fossil-Lagerstätte (Montana) by synchrotron, various lights and Reflectance Transformation Imaging (RTI). This revealed previously unappreciated anatomical details, on which we base evolutionary scenarios of how the internalization and other evolutionary steps in early coleoid evolution proceeded. We suggest that conch internalization happened rather suddenly including early growth stages while the ink sac evolved slightly later.
Language
  • English
Open access status
gold
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Persistent URL
https://folia.unifr.ch/global/documents/128540
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