Osteohistology of the silesaurid Sacisaurus agudoensis from southern Brazil (Late Triassic) and implications for growth in early dinosaurs
| Autor: | Marina Bento Soares, Fábio Hiratsuka Veiga, Ana Maria Ribeiro, Jennifer Botha-Brink, Jorge Ferigolo |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
010506 paleontology Ontogeny Zoology 010603 evolutionary biology 01 natural sciences Bone and Bones Dinosaurs Animals Femur dinosauriform lcsh:Science Archosauria bone microstructure 0105 earth and related environmental sciences Limb bone Multidisciplinary Tibia biology Fossils growth rates Biological evolution biology.organism_classification Biological Evolution Sacisaurus Closest relatives fibrolamellar bone lcsh:Q |
| Zdroj: | Anais da Academia Brasileira de Ciências, Vol 91, Iss suppl 2 Anais da Academia Brasileira de Ciências v.91 suppl.2 2019 Anais da Academia Brasileira de Ciências Academia Brasileira de Ciências (ABC) instacron:ABC Anais da Academia Brasileira de Ciências, Volume: 91 Supplement 2, Article number: e20180643, Published: 19 JUN 2019 |
| ISSN: | 1678-2690 0001-3765 |
| DOI: | 10.1590/0001-3765201920180643 |
| Popis: | The non-dinosaurian dinosauriform silesaurids are the closest relatives of crown-group dinosaurs and are thus, important for understanding the origins of that group. Here, we describe the limb bone histology of the Late Triassic silesaurid Sacisaurus agudoensis from the Candelária Sequence of the Santa Maria Supersequence, Rio Grande do Sul state, Brazil. The sampled bones comprise eight femora and one fibula from different individuals. The microscopic analysis of all elements reveals uninterrupted fibrolamellar bone tissue indicating rapid growth. A transition to slower growing peripheral parallel-fibered bone tissue in some individuals indicates a decrease in growth rate, suggesting ontogenetic variation within the sample. The osteohistology of Sacisaurus agudoensis is similar to that of other silesaurids and supports previous hypotheses that rapid growth was attained early in the dinosauromorph lineage. However, silesaurids lack the complex vascular arrangements seen in saurischian dinosaurs. Instead, they exhibit predominantly longitudinally-oriented primary osteons with few or no anastomoses, similar to those of some small early ornithischian dinosaurs. This simpler vascular pattern is common to all silesaurids studied to date and indicates relatively slower growth rates compared to most Dinosauria. |
| Databáze: | OpenAIRE |
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