Muscular Study Reveals How Giant 50-Ton Sauropod Dinosaurs Moved and Evolved - SciTechDaily

Limb muscles of the Bristol dinosaur, Thecodontosaurus antiquus.

New research led by the University of Bristol has revealed how giant 50-ton sauropod dinosaurs, like Diplodocus, evolved from much smaller ancestors, like the wolf-sized Thecodontosaurus.

In a new study published on January 19, 2022, in the journal Royal Society Open Science, researchers present a reconstruction of the limb muscles of Thecodontosaurus, detailing the anatomy of the most important muscles involved in movement.

This dinosaur was one of the first ever to be discovered and named by scientists, in 1836, but it still surprises scientists with new information about how the earliest dinosaurs lived and evolved.

Antonio Ballell, PhD student in Bristol’s School of Earth Sciences and lead author of the study, said: “The University of Bristol houses a huge collection of beautifully preserved Thecodontosaurus fossils that were discovered around Bristol.

Reconstructing muscles in extinct species requires this kind of exceptional preservation of fossils, but also a good understanding of the muscle anatomy of living, closely related species.

Antonio Ballell added: “In the case of dinosaurs, we have to look at modern crocodilians and birds, that form a group that we call archosaurs, meaning ‘ruling reptiles.’ Dinosaurs are extinct members of this lineage, and due to evolutionary resemblance, we can compare the muscle anatomy in crocodiles and birds and study the scars that they leave on bones to identify and reconstruct the position of those muscles in dinosaurs.”.

Professor Emily Rayfield, co-author of the study, said: “These kinds of muscular reconstructions are fundamental to understand functional aspects of the life of extinct organisms?

From the size and orientation of its limb muscles, the authors argue that Thecodontosaurus was quite agile and probably used its forelimbs to grasp objects instead of walking.

The muscular anatomy of Thecodontosaurus seems to indicate that key features of later sauropod-line dinosaurs had already evolved in this early species.

Professor Mike Benton, another co-author, said: “From an evolutionary perspective, our study adds more pieces to the puzzle of how the locomotion and posture changed during the evolution of dinosaurs and in the line to the giant sauropods.

Reconstructing the limb muscles of Thecodontosaurus gives us new information of the early stages of that important evolutionary transition.”.

Benton, 19 January 2022, Royal Society Open Science.