Argentine paleontologists have discovered the new dinosaur Meraxes Gigas mentioned, in which ‘Meraxes’ refers to a dragon from the fantasy series Game of Thrones† This dinosaur could not fly, but in size it was not inferior to a mythical creature, with a weight of four tons and a head of more than a meter in size: hence ‘Gigas’.
That the scientists could get a clear picture of Meraxes is due to the quality of the excavated specimen, with many intact bones from the legs, torso and tail. Also, almost the entire skull was still intact, showing deformations that would have pretended to be ornamental to attract potential mates. The pinnacle of the find: bones from the dino’s arms, which seem almost fussy in contrast to the rest of the massive stature.
The image of Meraxes may suggest that the new species is related to Tyrannosaurus Rexbut that is certainly not the case, the researchers write in on Thursday Current Biology† The T.rex is a so-called ‘Coelurosaur’, Greek for ‘hollow-tailed lizard’: the cross-section of the bones in the tail of these dinosaurs resemble a honeycomb. That has Meraxes not, and therefore belongs to another family, the relatively unknown carcharodontosauridae (‘lizard with shark teeth’), which was already ten million years before the arrival of the T.rex was extinct and lived on other continents.
So over millions of years there were several species with approximately the same building plan. ‘Giant predatory dinosaur with anything but impressive arms’ must therefore have been a very successful design.
short arms
That the arms were short because they simply had no function is not true: Meraxes and previously discovered fossils had strong strong bones and muscles in the arm, so the limbs most likely were not vestigial. Ideas about what their function actually were differ: some experts believe that the large dinosaurs could help themselves with short, strong arms after a fall, others argue that the short arms helped during mating.
The theory that the Argentine research agrees with is that there was less energy for the growth of arms, because everything had to be the size of the heads. Other fossils seem to confirm this connection, as does the Meraxescopy fits the picture. This theory does not explain what this type of dinosaur used their muscular arms for.
“It’s an easy explanation, but not necessarily better or worse than others,” said Melanie During, a vertebrate paleontologist at Uppsala University and not involved in the new study. “You can never see the limbs in action, so all theories are speculation to some degree.”
That’s not a huge problem, she says: with a discovery like this, researchers are almost forced to consider the nature of the arms. But, says During, preferably not too long, otherwise it would distract from the discovery of a “cool, big beast that wouldn’t have to back down from a fight with a T.rex†