Scientists have unearthed Australia's oldest known crocodile eggshells which may have belonged to drop crocs - creatures that climbed trees to hunt prey below.
The discovery of the 55-million-year-old eggshells was made in a sheep farmer's backyard in Queensland with the findings published in the Journal of Vertebrate Paleontology.
The eggshells belonged to a long-extinct group of crocodiles known as mekosuchines, who lived in inland waters when Australia was part of Antarctica and South America.
Co-author Prof Michael Archer said drop crocs were a bizarre idea but some were perhaps hunting like leopards - dropping out of trees on any unsuspecting thing they fancied for dinner.
Prof Archer, a palaeontologist at the University of New South Wales, elaborated that mekosuchine crocodiles could grow to about five metres and were plentiful 55 million years ago, long before their modern cousins arrived in Australia.
The drop croc eggshells were discovered several decades ago but only recently analyzed with the help of scientists in Spain.
It's a bizarre idea, Prof Archer said, but some were probably terrestrial hunters in the forests.
The findings add to earlier discoveries of younger mekosuchine fossils found in 25-million-year-old deposits in another part of Queensland.
The clay pit at Murgon, where these ancient fossils are excavated, has revealed a wealth of information about the period's biodiversity, including the world's oldest-known songbirds and Australia's earliest frogs and snakes.
Prof Archer remembers how he and a colleague sought permission to dig in a farmer's backyard in 1983, leading to numerous discoveries that promise even more surprises.
