Clarac F, Goussard F, Teresi L, Buffrénil Vde, Sansalone V
Sorbonne Universités UPMC Univ Paris 6, CNRS, Institut des Sciences de la Terre de Paris (ISTeP), 4 place Jussieu - BC 19, 75005 Paris, France; Département Histoire de la Terre, Museum National d'Histoire Naturelle, UMR 7207 (CR2P), Sorbonne Universités, MNHN/CNRS/UPMC, Bâtiment de Géologie, Paris Cedex 05 F-75231, France.
Département Histoire de la Terre, Museum National d'Histoire Naturelle, UMR 7207 (CR2P), Sorbonne Universités, MNHN/CNRS/UPMC, Bâtiment de Géologie, Paris Cedex 05 F-75231, France.
J Therm Biol. 2017 Oct;69:39-53. doi: 10.1016/j.jtherbio.2017.06.003. Epub 2017 Jun 10.
In order to assess the implication of the crocodylomorph ornamented osteoderms on the skin conduction during basking, we have performed three dimensional modeling and finite element analyses on a sample which includes both extant dry bones and well-preserved fossils tracing back to the Early Jurassic. In purpose to reveal the possible implication of the superficial ornamentation on the osteoderm heat conduction, we repeated the simulation on an equivalent set of smoothed 3D-modeled osteoderms. The comparison of the results evidenced that the presence of the apical sculpture has no significant impact on the osteoderm global conduction. Furthermore, as we also aimed to assess the influence of the inner bone porosity on the osteoderm conduction, we modified the heat equation parameters so that the 3D-modeled osteoderms successively score the compact and the cancellous bone properties (i.e. mass density, heat capacity, thermal conductivity and thermal diffusivity). Finally, we repeated the analyses using the soft-dermis properties which lead to outline that neither the degree of porosity nor the presence of the osteoderms (in itself) significantly modifies the heat conduction through the crocodylomorph skin. Consequently, as hypothesized by previous authors, if the dermal shield happens to be involved into heat capture during basking for crocodylians, this process must mainly rely on a convective effect based on the osteoderm relative degree of vascularization. This last assumption could thus explain why the crocodylians which produce little metabolic heat would carry an entire vascularized osteoderm shield.
为了评估鳄形超目动物有纹饰的骨板在晒太阳时对皮肤传导的影响，我们对一个样本进行了三维建模和有限元分析，该样本包括现存的干燥骨骼和可追溯到早侏罗世保存完好的化石。为了揭示表面纹饰对骨板热传导的可能影响，我们在一组等效的平滑三维建模骨板上重复了模拟。结果比较表明，顶端雕刻的存在对骨板整体传导没有显著影响。此外，由于我们还旨在评估内部骨孔隙率对骨板传导的影响，我们修改了热方程参数，以便三维建模的骨板依次呈现致密骨和松质骨的特性（即质量密度、热容量、热导率和热扩散率）。最后，我们使用软真皮特性重复了分析，结果表明孔隙率程度和骨板的存在（本身）都不会显著改变通过鳄形超目动物皮肤的热传导。因此，正如之前的作者所假设的那样，如果真皮盾在鳄类晒太阳时参与热量捕获，这个过程必须主要依赖于基于骨板相对血管化程度的对流效应。最后这个假设因此可以解释为什么产生很少代谢热的鳄类会带有整个血管化的骨板盾。
