作者
Torsten M Scheyer, John R Hutchinson, Olivier Strauss, Massimo Delfino, Jorge D Carrillo-Briceño, Rodolfo Sánchez, Marcelo R Sánchez-Villagra
发表日期
2019/11/27
期刊
Elife
卷号
8
页码范围
e49972
出版商
eLife Sciences Publications, Ltd
简介
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.
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TM Scheyer, JR Hutchinson, O Strauss, M Delfino… - Elife, 2019