The pigmented enamel of the shrew Blarina brevicauda is explored using different characterization techniques. A combination of microscopy and spectroscopy analyses permit to resolve unambiguously the iron composition of the pigmentation. The influence of this pigmentation on the enamel hardness is also determined and discussed in term of biomechanical function. If it is generally easy to determine the nanostructure of recent material, it becomes more complex for fossil material. Indeed, diagenesis impacts greatly their structure, especially at the nanoscale and differently according to their geological settings. The gigantism of the sauropods makes them one of the most fascinating animals that have been living on Earth. The structure of long bones and teeth of large Jurassic sauropods (Dinosauria) from two different geological sites (Tendaguru beds [Tanzania, Africa] and Morrison Formation [USA]) are investigated. Their long bones structures are analyzed in terms of crystallographic orientation, crystal size as well as the general arrangement of the tissue to obtain biological information (e.g. microstructure, mechanical performance linked to collagen fibre organization).The study of their teeth displays the taphonomical and diagenetic effects at the nano scale. These diagenetic data are then used to re-evaluate previous assumptions regarding the nanostructure of fossil hard tissues.

Contact : isabelle.combe@esrf.fr