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Fossilized titanosaurid vertebral ligament



Ben Creisler
bcreisler@gmail.com

A new paper:

D. Cary Woodruff, Nicholas J. Atwood &  Amelia Madill (2016)
The structural preservation of a titanosaurid (Dinosauria: Sauropoda)
vertebral ligament.
Cretaceous Research 60: 253–266
doi:10.1016/j.cretres.2015.12.009
http://www.sciencedirect.com/science/article/pii/S0195667115301348



Within the past decade exceptional preservation of original organic
components have been reported from several dinosaurian families,
including members of Sauropodomorpha. Here we document the partial
preservation of a vertebral ligament in the dorsal and sacral series
of a titanosaur. Unlike other cases of tissue preservation, this
structure does not represent biomineralization of the original organic
components. Histology, morphology, and comparative anatomy from extant
taxa as well as the preferential placement on the vertebral column
suggests that it represents the partial preservation of the nuchal
ligament. While preservation of other sauropod connective tissues are
known, this case represents the first reported non-biomineralized
tissue from a sauropod. In consideration of the location and external
and internal morphologies compared to modern vertebral ligaments, we
believe this structure to be the micritic replacement of the original
tissue via microbially-mediated processes. Along with the suggestive
external morphology, internally we interpret some of the unusual
structures to represent the remnants of the collagen and elastin
fascicles that are strongly overprinted by a clotted,
thrombolytic-like fabric recording microbial activity and deposition
of micrite prior to lithification. In consideration of the interpreted
depositional history, we theorize that post-deposition, bacteria
deposited the micrite as a byproduct of metabolization. Subsequently,
the recognition of this structure as a vertebral ligament, the largest
of such thus documented, substantiates previous findings on the
morphological attributes of sauropod vertebral ligaments.