Lirainosaurus bone histology, new paper

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

In case this new paper has not been mentioned. Note that 
the pdf can be downloaded for free.
http://www.springerlink.com/content/4n5804v361t08635/

Julio Company, 2010.
Bone histology of the titanosaur Lirainosaurus astibiae 
(Dinosauria: Sauropoda) from the Latest Cretaceous of 
Spain.
Naturwissenschaften (advance online publication) (Online 
First?) 
DOI: 10.1007/s00114-010-0742-3 

 
The titanosaur Lirainosaurus astibiae is the only 
sauropod species known from the Late Cretaceous of the 
Iberian Peninsula. Lirainosaurus did not reach a gigantic 
body size and is one of the smallest sauropods discovered 
to date. Histological analysis of Lirainosaurus bones, 
focused on diaphyseal transverse sections of appendicular 
elements, reveals that Lirainosaurus did not exhibit the 
osseous microstructure typical for large sauropods, but 
is comparable with that of the coeval titanosaurs 
Alamosaurus sanjuanensis, Ampelosaurus atacis, and 
Magyarosaurus dacus, and also shares histological traits 
with other small to medium-sized sauropodomorph 
dinosaurs. Lirainosaurus limb bones exhibit a laminar 
fibrolamellar bone microstructure interrupted by growth 
marks, fully obliterated in adulthood by intense 
secondary remodeling processes which tend to replace 
completely the primary cortex. Lirainosaurus attained 
smaller sizes than typical sauropods reducing the rate of 
primary periosteal osteogenesis and developing an 
extensive secondary remodeling well before the adult size 
was reached. Histological organization of Lirainosaurus 
long bones is more mature than observed in basal 
neosauropods at similar ontogenetic stage, documenting a 
case of peramorphosis by pre-displacement. This 
heterochronic growth would be a reversal of the 
accelerated pattern of bone deposition typical for the 
sauropod lineage. 

Keywords  Titanosauria -  Lirainosaurus  - Bone 
microstructure - Growth - Peramorphosis - Dwarfism