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Re: Anarosaurus (Sauropterygia) from Triassic of the Netherlands
Could someone send me a copy of this paper?
On Tue, Mar 20, 2012 at 7:37 AM, Ben Creisler <firstname.lastname@example.org> wrote:
> From: Ben Creisler
> A new online paper:
> Nicole Klein (2012)
> Postcranial morphology and growth of the pachypleurosaur Anarosaurus
> heterodontus (Sauropterygia) from the Lower Muschelkalk of
> Winterswijk, The Netherlands.
> Paläontologische Zeitschrift (advance online publication)
> DOI: 10.1007/s12542-012-0137-1
> Sauropterygia from the Muschelkalk are only found in lag deposits
> known as bone beds, and most of the material consists of isolated
> bones. Alpha taxonomy of Sauropterygia from the Germanic Basin which
> include Pachypleurosauria is thus based mainly on skull morphology of
> a few specimens. Articulated or associated postcranial material of
> pachypleurosaurs, associated with diagnostic skull material, is very
> rare in the Germanic Basin and currently occurs in larger numbers only
> in the Lower Muschelkalk of Winterswijk (Gelderland Province, The
> Netherlands), which continuously produces new material. For the first
> time, the morphology of several partially articulated skeletons of the
> pachypleurosaur Anarosaurus heterodontus is described and compared.
> Some of those specimens have skull material attached; others were
> identified as pachypleurosaurs on the basis of their long bone
> histology. The current study revealed that postcranial bones of A.
> heterodontus feature a diverse morphology reflecting differences
> during ontogeny. Thus, A. heterodontus specimens could be assigned to
> size classes (I–III). However, on the basis of morphology, histology,
> and maximal known size of isolated skulls and humeri, none of these
> specimens represent fully grown individuals. Growth mark counts of
> midshaft-femur samples, morphologically assigned to size class III,
> document that this size class was reached within the first year of
> life. Size class III continued into the second year of life, and then
> afterwards skeletal maturity was reached. Thus, a juvenile A.
> heterodontus grew very fast, which is also indicated by its bone
> tissue type, composed of a high number of radial vascular canals and a
> fast-deposited bone matrix. The assignment of isolated bones from
> Lower to Middle Muschelkalk localities to A. heterodontus is now
> possible with an extensive amended diagnosis of this taxon. This
> largely contributes to the understanding of taxonomical diversity and
> distribution. Morphological comparison of the postcranial skeleton of
> A. heterodontus with that of the two other valid pachypleurosaurs from
> the Germanic Basin, Anarosaurus pumilio and Dactylosaurus, supports
> their close phylogenetic relationship. Furthermore, the skeleton of A.
> heterodontus has no morphological or histological aquatic adaptation
> such as pachyostosis or pachyosteosclerosis and thus represents the
> least degree of aquatic adaptation within Pachypleurosauria.
> Some historical info about Anarosaurus at: