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 that they likely come from animals that 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. The research was carried out by paleontologists from the Palaeoscience Research Centre at the University of New England and the Australian Opal Centre in Lightning Ridge.
Artist’s depiction of an ornithopod dinosaur tending its nest. (Image: via James Kuether)
Small-bodied ornithopod dinosaur bones
The bones come from small-bodied ornithopod dinosaurs — two-legged herbivores that weighed roughly 20 kg 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 200 g when they died, less than 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 animals’ age. Justin Kitchener, a Ph.D. student at the University of New England, who also led the study, said:
“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.
“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.”
100 million years ago, when these animals were being born, Australia was much closer to the poles. The southeastern part 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, eggshells and tiny bones rarely survive to become fossils. Dr. Phil Bell, a University of New England paleontologist who recognized the significance of the tiny bones from Lightning Ridge, said:
“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.
“It’s the first clue we’ve had about where these animals were breeding and raising their young.”
Provided by: University of New England [Note: Materials may be edited for content and length.]
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