Sao Paulo Researchers Discover Key to Dinosaurs’ Evolution into Colossal Giants
Sao Paulo, Brazil – How did dinosaurs transform from small creatures to massive giants? Scientists at the State University of Campinas (UNICAMP) in São Paulo State, Brazil, believe they have finally unlocked the answer. In a groundbreaking study, they reveal that the air sac structures in the ancient dinosaur Macrocollum itaquii hold the key to understanding the evolution of these captivating creatures.
Macrocollum itaquii, which roamed South Brazil approximately 225 million years ago, is the oldest dinosaur ever studied with air sac structures. These bone cavities, similar to those found in modern birds, played a crucial role in enabling dinosaurs to capture more oxygen, regulate their body temperature, and survive the harsh conditions of their time. These adaptations allowed certain dinosaurs, such as the formidable Tyrannosaurus rex and Brachiosaurus, to grow into colossal creatures.
“Air sacs made their bones less dense, enabling them to reach lengths of over 30 meters,” says Tito Aureliano, lead author of the study, in a recent media release.
Aureliano’s research, conducted as part of his PhD, sheds light on the remarkable transformation of dinosaurs from being merely one meter long to reaching astonishing lengths. The study was carried out under the broader project “Taphonomic Landscapes,” funded by The São Paulo Research Foundation (FAPESP), which investigates the preservation and fossilization of organisms.
Fresia Ricardi-Branco, a professor at UNICAMP and the principal investigator of the project, emphasizes the significance of M. itaquii in the context of dinosaur evolution.
“This dinosaur walked the Earth during the Triassic period and paved the way for the remarkable diversity we see in the Jurassic and Cretaceous periods. The presence of air sacs gave dinosaurs an evolutionary advantage over other groups, allowing them to diversify rapidly,” explains Ricardi-Branco.
The recent discovery challenges previous assumptions about air sac evolution. The research team found internal pneumatic chambers in M. itaquii—a new type of tissue with an intermediate texture that they propose to call “protocamerate.” This finding contradicts the widely accepted hypothesis that air sacs evolved from camerate to camellate structures. Additionally, the researchers discovered that air sacs existed in the cervical and dorsal regions of the dinosaur’s spine, contrary to previous theories suggesting they only appeared in the abdominal region.
“It seems that evolution experimented with different forms until it arrived at the definitive system, where air sacs spanned from the cervical region to the tail. It was not a linear process,” explains Aureliano.
By uncovering the role of air sacs in dinosaur evolution, this study provides invaluable insights into the extraordinary world of these prehistoric creatures. The discovery of M. itaquii’s unique anatomical features revolutionizes our understanding of dinosaur development, paving the way for further exciting revelations about their ancient existence.
The findings from the research have been published in the journal Anatomical Record.
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