An analysis of the growth rings in the leg bones of 17 individuals of Tyrannosaurus rex reveals that these dinosaurs matured much more slowly than previously thought. It took them 40 years to reach maturity.
The largest analysis of fossils of T. rex (Tyrannosaurus rex) ever held, this Wednesday at PeerJsuggests that this giant, ferocious Cretaceous predator was a late to reach maturity, taking between 35 and 40 years to reach it.
The new study’s findings also fuel debate over whether there were multiple species of T. rex instead of just oneand whether smaller specimens, once considered juveniles, are in reality a smaller species called Nanotyrant.
Based on studies carried out two decades ago, it was thought that T. rex reached its maximum weight of 8 tons in about two decades and that the animals probably only lived to be 30 years old.
The new research collected samples from the thigh and tibia bones of 17 individuals, ranging in age from juveniles to fully grown adults, constituting the largest collection of growth data ever assembled on T. rex.
Scientists studied the microstructure of bone tissue, including the growth rings that form annually, just as they do on a tree trunk. However, older growth rings are destroyed as the bone marrow cavity enlarges, so the team needed access to as many specimens with overlapping growth stages as possible.
“This is why our sample size and age range are so important and what makes this study different from previous ones”, says the research leader, to . Holly Ballardfrom Oklahoma State University (EUA).
The analysis reveals that the T. rex grew more slowly than previously thought previously and that its growth rate varied depending on environmental conditions.
However, it is not possible to determine the maximum age of T. rex because, once maturity was reached, the animals stopped forming growth rings.
