Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians
Scheyer, Torsten M. (University of Zurich. Paläontologisches Institut und Museum)
Hutchinson, John R. (University of London. Royal Veterinary College (Hatfield, Regne Unit))
Delfino, Massimo (Institut Català de Paleontologia Miquel Crusafont)
Strauss, Olivier (University of Zurich. Paläontologisches Institut und Museum)
Carrillo-Briceño, Jorge Domingo (University of Zurich. Paläontologisches Institut und Museum)
Sánchez, Rodolfo (Museo Paleontológico de Urumaco (Urumaco, Veneçuela))
Sánchez-Villagra, Marcelo R. (University of Zurich. Paläontologisches Institut und Museum)

Date:	2019
Abstract:	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.
Grants:	Ministerio de Economía y Competitividad CGL2016-76431-P European Commission 695517
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Evolutionary biology ; Crocodylia ; Variation ; Hox ; Miocene ; Evo-devo ; Gigantism
Published in:	eLife, 2019, art. e49972, ISSN 2050-084X

DOI: 10.7554/eLife.49972
PMID: 31843051

Article 19 p, 5.8 MB

Suplement 15 p, 10.7 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut Català de Paleontologia Miquel Crusafont (ICP)
Articles > Research articles
Articles > Published articles