Palm-sized baby dinosaurs revealed in Australia


Share post:

Researchers have uncovered the first baby dinosaurs from Australia. The bones were discovered at several sites along the south coast of Victoria and near the outback town of Lightning Ridge in New South Wales. Some of the bones are so tiny, they likely come from animals that had died while they were still in their eggs. Slightly larger bones from Victoria come from animals that had recently hatched but were probably nest-bound.

Palm-sized baby dinosaurs revealed in Australia
The femur (thigh bone) of a hatchling-sized ornithopod dinosaur from Victoria compared
to an Australian one-dollar coin [Credit: Justin Kitchener]

The research was carried out by palaeontologists from the Palaeoscience Research Centre at the University of New England and the Australian Opal Centre in Lightning Ridge.

The bones come from small-bodied ornithopod dinosaurs—two legged herbivores that weighed roughly 20kg when full grown—similar to Weewarrasaurus, which was recently discovered by members of the same team at Lightning Ridge. By comparison, the baby dinosaurs were only about 200g when they died, less that the weight of a cup of water.

While the eggs themselves were not found, researchers used growth rings in the bones, similar to the rings in a tree trunk, to estimate the animal’s age. “Age is usually estimated by counting growth rings, but we couldn’t do this with our two smallest specimens, which had lost their internal detail,” says Justin Kitchener, a Ph.D. student at the University of New England, who also led the study. “To get around this, we compared the size of these bones with the size of growth rings from the Victorian dinosaurs. This comparison confidently places them at an early growth stage, probably prior to, or around the point of hatching.”

Palm-sized baby dinosaurs revealed in Australia
Artist’s depiction of an ornithopod dinosaur tending its nest
[Credit: James Kuether]

100 million years ago, when these animals were being born, Australia was much closer to the poles. Southeastern Australia would have been between 60°S and 70°S, equivalent to modern day Greenland. Although the climate at these latitudes was relatively warmer than they are today, like some Antarctic penguins, these dinosaurs would have endured long dark winters and possibly burrowed or hibernated to survive.

Because they are so delicate, egg shell and tiny bones rarely survive to become fossils. “We have examples of hatchling-sized dinosaurs from close to the North Pole, but this is the first time we’ve seen this kind of thing anywhere in the Southern Hemisphere,” says Dr. Phil Bell, a University of New England palaeontologist who recognised the significance of the tiny bones from Lightning Ridge. “It’s the first clue we’ve had about where these animals were breeding and raising their young.”

The study was published today in the journal Scientific Reports.

Source: University of New England [December 19, 2019]



Related articles

Dolphin ancestor’s hearing was more like hoofed mammals than today’s sea creatures

Vanderbilt University paleontologists are looking into the evolutionary origins of the whistles and squeaks that dolphins and porpoises...

New Mosasaur is a link between iconic species

Scientists have discovered a new species of mosasaur, large, carnivorous aquatic lizards that lived during the late Cretaceous....

Scientists solve mystery shrouding oldest animal fossils

Scientists from The Australian National University (ANU) have discovered that 558 million-year-old Dickinsonia fossils do not reveal all...

Dinosaur casts light on late burst of evolution

A dinosaur fossil that almost went undiscovered is giving scientists valuable clues about a family of creatures that...

4,000-year-old termite mounds found in Brazil are visible from space

Researchers reporting in Current Biology have found that a vast array of regularly spaced, still-inhabited termite mounds in...

Fossil crab reveals a new branch in the tree of life

A new fossil from the dinosaur era challenges the understanding of evolution. In a paper published in Science...

Auction house to sell composite skeleton of a dodo bird

Summers Place Auctions is selling what it describes as a rare composite skeleton of a dodo bird, a...

Ray-finned fish survived mass extinction event

Ray-finned fish, now the most diverse group of backboned animals, were not as hard hit by a mass...