#macrocollum

[ Life reconstruction of Macrocollum itaquii by Márcio L. Castro. ]

"The missing link has just been found, bridging the gap between the earliest dinosaurs, which varied significantly in size from mere centimeters to a maximum of 3 meters, and more recent giants that could be more than twice the length of a bus and have so much appeal to the popular imagination. Macrocollum itaquii, which was discovered in the region of Agudo in the Rio Grande do Sul state of South Brazil and dates back 225 million years, is the most ancient dinosaur known to have structures referred to as air sacs. These bone cavities, which persist in present-day birds, enabled dinosaurs to capture more oxygen, keep their bodies cool, and withstand the harsh conditions of their era. They also helped some become giants: Tyrannosaurus rex and Brachiosaurus, for example. An article on the study that led to the discovery was published in the journal Anatomical Record. Two of its authors are researchers supported by FAPESP at the State University of Campinas (UNICAMP) in São Paulo state. “Air sacs made their bones less dense, allowing them to grow to more than 30 meters in length,” said Tito Aureliano, first author of the article. The study was conducted as part of his PhD research at the Institute of Geosciences (IG-UNICAMP). “M. itaquii was the largest dinosaur of its time, with a length of about 3 meters. A few million years before then, the largest dinosaurs were about 1 meter long. Air sacs certainly facilitated this increase in size,” Aureliano added."