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Data from: Palaeobiology of the early sauropodomorph Mussaurus patagonicus inferred from its long bone histology

Citation

Cerda, Ignacio (2022), Data from: Palaeobiology of the early sauropodomorph Mussaurus patagonicus inferred from its long bone histology, Dryad, Dataset, https://doi.org/10.5061/dryad.8cz8w9gs3

Abstract

We present here a detailed histological study of long bones from an ontogenetic series of Mussaurus patagonicus, an early sauropodomorph from the Early Jurassic of Argentina. Twenty long bones, including humeri, femora and fibulae, obtained from thirteen individuals of different body sizes were sampled for histological analysis. In general terms, the cortical bone is formed by a well vascularized fibrolamellar and parallel fibred bone. Except for the smaller individuals, cyclical growth marks (CGMs) are well recorded in all the specimens, but their number and relative position is highly variable. Mussaurus exhibits marked variation regarding relative growth rates, with some individuals growing much faster than others. Such variation affects the size of the adult individuals, which results in a poor correlation between the body size and the age/ontogenetic stage for this taxon. These discrepancies may be related to sexual dimorphism and/or developmental plasticity. Intraspecific variation is also recorded with regard to the growth strategies, which can vary from cyclical, as in other early sauropodomorphs, to continuous, as reported in sauropods. Sexual maturity appears to be reached between 23 and 31 years, which is delayed in comparison to other early sauropodomorphs, but more compatible to derived sauropods. The attainment of somatic maturity appears to be reached about 14 years after the onset of sexual maturity. Mussaurus is a sauropodiform, phylogenetically closer to sauropods than most other sauropodomorphs, and therefore provides critical information for understanding paleobiological aspects relevant to the origin of sauropods and the onset of gigantism in this lineage.

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