Exploring dinosaur growth

Jun 28, 2013
Exploring dinosaur growth
Psittacosaurus skeleton cast, Psittacosaurus meileyingensis. Credit: The Children's Museum of Indianapolis

Tracking the growth of dinosaurs and how they changed as they grew is difficult. Using a combination of biomechanical analysis and bone histology, palaeontologists from Beijing, Bristol, and Bonn have shown how one of the best-known dinosaurs switched from four feet to two as it grew.

Psittacosaurus, the 'parrot dinosaur' is known from more than 1000 specimens from the Cretaceous, 100 million years ago, of China and other parts of east Asia. As part of his PhD thesis at the University of Bristol, Qi Zhao, now on the staff of the Institute for Vertebrate Paleontology in Beijing, carried out the intricate study on bones of babies, juveniles and adults.

Dr Zhao said: "Some of the bones from baby Psittacosaurus were only a few millimetres across, so I had to handle them extremely carefully to be able to make useful bone sections. I also had to be sure to cause as little damage to these valuable specimens as possible."

With special permission from the Beijing Institute, Zhao sectioned two arm and two leg bones from 16 individual dinosaurs, ranging in age from less than one year to 10 years old, or fully-grown. He did the intricate sectioning work in a special palaeohistology laboratory in Bonn, Germany.

The one-year-olds had long arms and short legs, and scuttled about on all fours soon after hatching. The bone sections showed that the were growing fastest when the animals were ages one to three years. Then, from four to six years, arm growth slowed down, and the showed a massive growth spurt, meaning they ended up twice as long as the arms, necessary for an animal that stood up on its as an adult.

Professor Xing Xu of the Beijing Institute, one of Dr Zhao's thesis supervisors, said: "This remarkable study, the first of its kind, shows how much information is locked in the bones of dinosaurs. We are delighted the study worked so well, and see many ways to use the new methods to understand even more about the astonishing lives of the dinosaurs."

Professor Mike Benton of the University of Bristol, Dr Zhao's other PhD supervisor, said: "These kinds of studies can also throw light on the evolution of a dinosaur like Psittacosaurus. Having four-legged babies and juveniles suggests that at some time in their ancestry, both juveniles and adults were also four-legged, and Psittacosaurus and in general became secondarily bipedal."

The paper is published today in Nature Communications.

Explore further: More than two dozen articles provide insights on mummies

Related Stories

Muscle reconstruction reveals how dinosaurs stood

Jun 21, 2012

(Phys.org) -- Much is known about the dinosaurs that walked on 4 legs like Stegosaurus and Triceratops, but their stance has been a topic of debate, until now. Scientists at the Natural History Museum have ...

What's in a dinosaur name?

Sep 17, 2008

(PhysOrg.com) -- A new species of dinosaur is named somewhere in the world every two weeks. But are they all new species, or do the newly-discovered bones really belong to a dinosaur already identified?

Dinosaur shook tail feathers for mating show

Jan 16, 2013

(Phys.org)—A University of Alberta researcher's examination of fossilized dinosaur tail bones has led to a breakthrough finding: some feathered dinosaurs used tail plumage to attract mates, much like modern-day ...

Recommended for you

More than two dozen articles provide insights on mummies

May 22, 2015

In a special issue, The Anatomical Record ventures into the world of human mummified remains. In 26 articles, the anatomy of mummies is exquisitely detailed through cutting edge examination, while they are put in historical, archeo ...

The Bronze Age Egtved Girl was not from Denmark

May 21, 2015

The Bronze Age Egtved Girl came from far away, as revealed by strontium isotope analyses of the girl's teeth. The analyses show that she was born and raised outside Denmark's current borders, and strontium ...

Oldest-known stone tools pre-date Homo

May 20, 2015

Scientists working in the desert badlands of northwestern Kenya have found stone tools dating back 3.3 million years, long before the advent of modern humans, and by far the oldest such artifacts yet discovered. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.