Scientists say they have found the oldest known eggshells of Australian crocodiles, a discovery that could shed light on ancient reptiles that could have hunted prey by dropping them from trees.
The eggshells belonged to mecosuchine crocodiles, a prehistoric creature that dominated Australian waters 55 million years ago – long before saltwater and freshwater crocodiles arrived on the continent around 3.8 million years ago.
Paleontologist Michael Archer said mecosuchine crocodiles can grow to at least 5 meters (about 16 feet) long, and some hunt from trees. Australian scientists have named them “crocs” – a reference to the feared “dripping bear”, the angry, carnivorous cousin of the country’s beloved koalas, or so the legend goes.
“It’s a strange idea. But it seems that some of them were terrestrial hunters in forests,” said Professor Archer of the University of New South Wales in Sydney, who participated in the study.
“Perhaps they hunted like leopards, dropping out of trees for whatever unsuspecting thing they came up with for dinner,” he said in a statement.
An international team of scientists, led by the Institut Català de Paleontologia Miquel Crusafont in Barcelona, excavated the fossils from a backyard ranch in southeast Queensland and studied them.. They reported their findings Tuesday in the Journal of Vertebrate Paleontology.
Ancient crocodile eggshells are helping scientists understand the anatomy of these reptiles, as well as their reproductive methods and adaptations, said Xavier Panadès i Blas, lead author of the study.
“They preserve microstructural and geochemical signals that tell us not only what species of animals laid them, but also where they nested and how they bred,” he said in a statement.
Mecosuchine crocs are thought to have become extinct in Australia around 3,000 years ago. They may have lost much of their terrestrial habitat to encroaching land, a situation compounded by growing competition with other predators and dwindling prey, said co-author Michael Stein, a research associate at the University of New South Wales.
The eggshell fragments were unearthed at a site near Murgon, a small town three and a half hours’ drive from Brisbane. – Mina Bassarova
Trove in the yard
The exact location of the discovery is a small town called Murgon, about three and a half hours’ drive from Brisbane, the capital of Queensland.
Archer said he and his colleagues had been digging there since 1983. and can still remember how it all began.
“My UNSW colleague Henk Godhelp and I drove to Murgon, parked on the side of the road, grabbed shovels, knocked on doors and asked if we could dig up their yard,” he said.
Archer recalled that the residents “smiled and said ‘of course'” when they heard their homes were standing on some prehistoric treasure.
“And it’s quite clear that from the many interesting animals we’ve already found in this deposit since 1983, we know that there will be many more surprises as we dig more,” he said.
Determining an extinct species by eggshell is inherently difficult, said Dean Lomax, a paleontologist and author of The Secret Lives of Dinosaurs – Unearthing the. Real Behavior of prehistoric animals.” He was not involved in the new study.
But given that the eggshell was found in the same geological deposits and the only known mecosuchine fossils from the period, Lomax said the authors made a strong case.
“I think one of the most important things is that matching fossil eggshells and the croc that laid them can provide new information,” he said. “This will help us understand not only how they reproduced and where they laid their eggs, but this connection can also help us understand the lifestyle of these unusual crocs.”
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