Bone cavities, understood as air sacs, emerged in precursors of long-necked dinosaurs approximately 225 million years ago, as evidenced by a specimen discovered in Rio Grande do Sul, South Brazil. The research also suggests that air sacs did not develop as linearly as scientists believe. Air sacs offered dinosaurs an evolutionary advantage over other groups, such as mammals, and they were able to diversify much faster.”
The vertebrae in which the air sacs were discovered also changed what was known about the development of these structures. Here, however, the authors discovered clear evidence of air sacs in the cervical and dorsal areas, with no sign of the structures in the stomach region.
Bone cavities, understood as air sacs, emerged in precursors of long-necked dinosaurs approximately 225 million years back, as evidenced by a specimen discovered in Rio Grande do Sul, South Brazil. The research also indicates that air sacs did not progress as linearly as scientists think. Credit: Márcio L. Castro
Bone cavities called air sacs emerged in the precursors of long-necked dinosaurs around 225 million years back, according to the analysis of a specimen found in Rio Grande do Sul state, South Brazil.
The missing out on link has simply been discovered, bridging the gap in between the earliest dinosaurs, which differed considerably in size from mere centimeters to an optimum of 3 meters, and more recent giants that could be more than two times the length of a bus and have a lot interest the popular creativity.
Macrocollum itaquii, which was found 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 described as air sacs.
These bone cavities, which continue contemporary birds, enabled dinosaurs to capture more oxygen, keep their bodies cool, and stand up to the harsh conditions of their era. They also assisted some become giants: Tyrannosaurus rex and Brachiosaurus.
A post on the research study that caused the discovery was released in the journal Anatomical Record. 2 of its authors are scientists 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,” stated Tito Aureliano, very first author of the article. The research study was conducted as part of his PhD research study 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 biggest dinosaurs had to do with 1 meter long. Air sacs certainly facilitated this increase in size,” Aureliano included.
The study was a phase of the project “Taphonomic landscapes”, funded by FAPESP. Taphonomy is the research study of how organisms decay and become maintained or fossilized in the paleontological record.
The principal investigator for this project was Fresia Ricardi-Branco, the penultimate author of the article and a teacher at IG-UNICAMP.
” This was one of the first dinosaurs to stroll the Earth, in the Triassic period,” she said. “The air sac adaptation enabled it to grow and hold up against the environment in this period and later, in the Jurassic and Cretaceous. Air sacs offered dinosaurs an evolutionary benefit over other groups, such as mammals, and they had the ability to diversify quicker.”
In a previous research study, the group revealed that the earliest fossils found so far did not have air sacs, taking their absence as an indication that this quality developed at least 3 times individually.
M. itaquii was a biped, a sauropodomorph, and a forefather of the giant quadrupeds with a little head, and a neck at least as long as the trunk.
Nonlinear development
Until air sacs were discovered in M. itaquii, these vertebral cavities were known to include either camerate or camellate tissue, the previous referring to hollow spaces observed by microtomography, and the latter to spongy bone. According to the authors, in this case, they found “internal pneumatic chambers”, which are “neither camerate nor camellate, however a brand-new type of tissue with an intermediate texture”. They propose to call the brand-new structures “protocamerate”, as they “are not big enough to be thought about cams, but likewise present a camellate selection internally”.
” The most commonly held hypothesis up until now was that the air sacs started as cam and developed into camellae. Our proposition, based upon what we observed in this specimen, is that this other form existed first of all,” Aureliano said.
The vertebrae in which the air sacs were found likewise altered what was understood about the advancement of these structures. Based on the fossils examined formerly, other research groups proposed that air sacs first appeared in the stomach area and did not appear in the cervical region till the early Jurassic (190 million years ago), a long time after the period in which M. itaquii lived. Here, however, the authors discovered clear evidence of air sacs in the cervical and dorsal areas, without any sign of the structures in the stomach region.
” Its as if development had performed various experiments till it reached the conclusive system, in which air sacs run from the cervical region to the tail. It wasnt a linear procedure,” Aureliano said.
Recommendation: “The origin of an invasive air sac system in sauropodomorph dinosaurs” by Tito Aureliano, Aline M. Ghilardi, Rodrigo T. Müller, Leonardo Kerber, Marcelo A. Fernandes, Fresia Ricardi-Branco and Mathew J. Wedel, 27 March 2023, The Anatomical Record.DOI: 10.1002/ ar.25209.
The research study was funded by the São Paulo Research Foundation.
