Fossil shows evidence
of live birth
A UQ geologist has helped uncover evidence of live birth among a species of dinosaur, changing the way scientists look at dinosaur evolution.
UQ School of Earth and Environmental Sciences Head Professor Jonathan Aitchison was part of a team that discovered a remarkable 250 million-year-old fossil in China that shows an embryo inside a mother.
Professor Aitchison said the Dinocephalosaurus fossil was an archosauromorph, a long-necked marine animal and distant relative of the crocodile, that flourished in the shallow seas of South China in the Middle Triassic Period.
The creature was a fish-eater, snaking its long neck from side to side to snatch its prey. Its fossil was one of many astonishingly well-preserved specimens from Luoping Biota sites in south-western China.
Professor Aitchison said the Dinocephalosaurus fossil provided the first evidence for live birth in an animal group previously thought to exclusively lay eggs.
“Live birth is common among lizards and snakes, where the babies sometimes ‘hatch’ inside their mother and emerge without a shelled egg,” he said.
“But, until recently, it was thought the third major group of living land vertebrates, crocodiles and birds (part of the wider group archosauromorpha), only laid eggs.
We discovered it was in the wrong part of the skeleton, but also it was facing the wrong way in the stomach.
“It shows that live birth did happen and that has all sorts of ramifications for evolution.”
Professor Aitchison has collaborated with lead researcher Professor Jun Liu, from Hefei University of Technology China, and other palaeontologists in the US, the UK and Australia. The research has been published in the journal Nature Communications.
UQ School of Earth and Environmental Sciences Head Professor Jonathan Aitchison.
Professor Liu said the discovery pushes back evidence of reproductive biology in the archo-sauromorpha group by 50 million years.
“Information on reproductive biology of archosauromorphs before the Jurassic Period was not available until our discovery, despite a 260-million-year history of the group.”
For more information about the UQ School of Earth and Environmental Sciences, visit sees.uq.edu.au.