Dinosaur had growth spurt when it was younger, fossils show
- Published
A Whatcheeria skull in the collections of the Field Museum
A dinosaur that lived more than 340 million years ago had a growth spurt in its youth, fossils have revealed.
The Whatcheeria, a lake-dwelling super-predator, was one of the biggest carnivores of the time.
Now a study of fossils in the Field Museum of Natural History in Chicago has shown that unlike most reptiles, the Whatcheeria grew rapidly when it was young with its growth slowing down after that.
There are around 350 Whatcheeria specimens in the Field Museum from single bones to complete skeletons.
The fossils were discovered in a limestone quarry near the town of What Cheer, Iowa.
With so many different fossils available the researchers were able to look at the differences between them.
"Examining these fossils is like reading a storybook, and we are trying to read as many chapters as possible by looking at how juveniles grow building up to adulthood," said Megan Whitney, the study's lead author, a professor at Loyola University in Chicago.
A bit like how people can examine the rings of a trunk to see how old a tree is when an animal is growing new layers of bone grow each year.
By looking at how thick the rings are experts can work out if an animal is growing continuously or not.
The Whatcheeria was a large predator
Birds and mammals grow a lot when they are younger and stop when they are older, but other animals like crocodiles and other reptiles keep growing bit by bit their whole lives.
Experts thought that the Whatcheeria would be more like reptiles, growing "slow and steady", but instead when they studied the bones they found evidence that the dinosaur grew rapidly early on its life.
"If you're going to be a top predator, a very large animal, it can be a competitive advantage to get big quickly as it makes it easier to hunt other animals, and harder for other predators to hunt you," said Stephanie Pierce who also worked on the study.
