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Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians.
Journal article

Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians.

  • Scheyer TM University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland.
  • Hutchinson JR Structure & Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, United Kingdom.
  • Strauss O University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland.
  • Delfino M Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy.
  • Carrillo-Briceño JD University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland.
  • Sánchez R Museo Paleontológico de Urumaco, Urumaco, Venezuela.
  • Sánchez-Villagra MR University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland.
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  • 2019-12-18
Published in:
  • eLife. - 2019
Crocodylia
Hox
Miocene
evo-devo
evolutionary biology
gigantism
variation
Alligators and Crocodiles
Animals
Bone and Bones
Extinction, Biological
Paleontology
Phylogeny
English The number of precaudal vertebrae in all extant crocodylians is remarkably conservative, with nine cervicals, 15 dorsals and two sacrals, a pattern present also in their closest extinct relatives. The consistent vertebral count indicates a tight control of axial patterning by Hox genes during development. Here we report on a deviation from this pattern based on an associated skeleton of the giant caimanine Purussaurus, a member of crown Crocodylia, and several other specimens from the Neogene of the northern neotropics. P. mirandai is the first crown-crocodylian to have three sacrals, two true sacral vertebrae and one non-pathological and functional dorsosacral, to articulate with the ilium (pelvis). The giant body size of this caiman relates to locomotory and postural changes. The iliosacral configuration, a more vertically oriented pectoral girdle, and low torsion of the femoral head relative to the condyles are hypothesized specializations for more upright limb orientation or weight support.
Language
  • English
Open access status
gold
Identifiers
Persistent URL
https://sonar.ch/global/documents/47721
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