I. A. Cerda, Pol, D. and Cinsamy A.
Here, we describe the
bone histology of juvenile specimens of the basal sauropodomorph Mussaurus patagonicus and interpret its
significance in terms of the early growth dynamics of this taxon. Thin sections
from three juvenile specimens (femur length, 111–120 mm) of Mussaurus were analysed. The sampled bones
consist of multiple postcranial elements collected from the Late Triassic Laguna Colorada Formation (El Tranquilo
Group, Patagonia). The cortical bone is composed of fibrolamellar
bone tissue. Vascularisation is commonly laminar or plexiform in the long
bones. Growth marks are absent in all the examined samples. The ‘epiphyses’ of
long bones are all formed by well-developed hypertrophied calcified cartilage.
The predominance of woven-fibred bone matrix in cortical bones indicates a fast
growth rate in the individuals examined. Moreover, given the existence of
growth marks in adult specimens of Mussaurus, as in other sauropodomorphs, and
assuming that the first lines of arrested growth was formed during the first
year of life, the absence of growth marks in all the bones suggest that the
specimens died before reaching their first year of life. Compared with the African
taxon Massospondylus carinatus (another
basal sauropodomorph for which the bone histology has been previously studied),
it appears that Mussaurus had a higher early growth rate than Massospondylus.
Cerda, I. A., Pol, D. and
Chinsamy A. 2013. Osteohistological insight into the early stages of growth in Mussaurus
patagonicus (Dinosauria, Sauropodomorpha) Historical Biology: An International
Journal of Paleobiology, DOI:10.1080/08912963.2012.763119
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