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Re: Bone ornamentation mechanisms in crocodylomorphs (Crurotarsi) (free pdf)

Ben Creisler

The pdf is now free:


On Tue, Dec 9, 2014 at 8:41 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
> A new online paper:
> V. de Buffrénil, F. Clarac, M. Fau, S. Martin, B. Martin, E. Pellé and
> M. Laurin (2014)
> Differentiation and growth of bone ornamentation in vertebrates: A
> comparative histological study among the Crocodylomorpha.
> Journal of Morphology (advance online publication)
> DOI: 10.1002/jmor.20351
> http://onlinelibrary.wiley.com/doi/10.1002/jmor.20351/abstract
> Bone ornamentation, that is, hollow (pits and grooves) or protruding
> (ridges) repetitive reliefs on the surface of dermal bones, is a
> frequent, though poorly studied and understood, feature in
> vertebrates. One of the most typical examples of this characteristic
> is given by the Crurotarsi, a taxon formed by the crocodilians and
> their closest allies, which generally display deep ornamentation on
> skull roof and osteoderms. However, the ontogenetic process
> responsible for the differentiation and development of this character
> remains controversial. This study was conducted to settle the question
> on histological and microanatomical evidence in several crurotarsan
> taxa. Observational and experimental data in extant and extinct
> crocodyliforms show that bone ornamentation is initially created, and
> later maintained during somatic growth (that is indefinite in
> crocodilians), by a complex process of bone remodeling comprising
> local resorption of superficial bone cortices, followed by partial
> reconstruction. The superficial reliefs of crocodilian dermal bones
> are thus permanently modified through pit enlargement, drift,
> stretching, shrinking, or complete filling. Ridges are also remodeled
> in corresponding ways. These processes allow accommodation of unitary
> ornamental motifs to the overall dimensions of the bones during
> growth. A parsimony optimization based on the results of this study,
> but integrating also published data on bone histology in
> non-crocodyliform crurotarsans and some non-crurotarsan taxa, suggests
> that the peculiar mechanism described above for creating and
> maintaining bone ornamentation is a general feature of the Crurotarsi
> and is quite distinct from that attributed by previous authors to
> other vertebrates.