RESUMO
Information on the adaptation of bone structures during evolution is rare since histological data are limited. Micro- and nano-computed tomography of a fossilized vertebra from Champsosaurus sp., which has an estimated age of 70-73 million years, revealed lower porosity and higher bone density compared to modern Crocodylidae vertebrae. Mid-infrared reflectance and energy dispersive X-ray mapping excluded a petrification process, and demonstrated a typical carbonate apatite distribution, confirming histology in light- and electron microscopy of the preserved vertebra. As a consequence of this evolutionary process, the two vertebrae of modern Crocodylidae show reduced overall stiffness in the finite element analysis simulation compared to the fossilized Champsosaurus sp. vertebra, with predominant stiffness along the longitudinal z-axes.
Assuntos
Fósseis , Coluna Vertebral , Densidade Óssea , Simulação por Computador , Análise de Elementos Finitos , Vértebras Lombares/anatomia & histologia , Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
A new imaging method for computerized tomography is presented and some examples are demonstrated. The method is based on the collection of all image data of a chosen block of tissue and enables the examiner to perform multiplanar reconstructions of high quality in any direction, even in oblique planes. In order to achieve a better orientation, the block of tissue can also be visualized at the same time on the reconstruction.
