The discovery of 100 million-year-old fossils in outback Queensland has shed new light on creatures from Australia’s ancient inland sea.
The skull of a giant predator fish called cooyoo, which revealed for the first time its formidable teeth, was unearthed last month at a farm near Julia Creek in the state’s north-west by paleontologist Timothy Holland.
This was followed weeks later by another remarkable find, a fossilised clam containing up to 30 small fish Holland says rate as the best preserved specimens from the ancient sea that existed when Australia and Antarctica were one continent.
“I was looking at a spot where there’d been fossils found years before and I was turning over these slabs of mudstone and I guess I just grabbed onto the right one and flipped it over,” Holland said.
“I could see these massive jaws and the eye socket of this very large fish, almost like it was staring up at me.”
Holland said this specimen of the cooyoo, a three metre fish threatened only by sharks or large marine reptiles, had “a very well-preserved upper jaw which shows for the first time that this fish had larger teeth than previously thought”.
Instead of comb-like teeth, the cooyoo boasted “long, pointed conical teeth which were excellent for latching on to slippery fish prey”.
On a subsequent return to the site to find a missing piece of the cooyoo skull, Royal Melbourne Institute of Technology student Paul Ter made the “highly unusual” find of small fish, their skeletons preserved whole inside the clam, just 20m away.
“We hardly have any small fish preserved from the inland sea,” Holland said. “They seem to have all been eaten up by predators or became jumbled up through currents, or scavengers have got to the remains.
“But it seems like these little fish were somehow protected inside the shell of this clam, which is amazing.
“Paul was looking for small things because he studies trace fossils and burrows, so he kind of had his eye in looking for things that other people may have missed.”
Both fossils went on display this week in the Kronosaurus Korner museum in nearby Richmond.
