The discovery of a 100 million-year-old fossil skull that belongs to a giant predator fish called cooyoo has revealed its formidable teeth for the first time. It was found by paleontologist Timothy Holland in outback Queensland, Australia.
The discovery also included a number of small fish, and has given some insight on the creatures from Australia’s ancient inland sea. The fossils are on display at the Kronosaurus Corner museum in Richmond.
A fossilized clam that contained up to 30 small fish was also found a week later.
Holland said these are “the best preserved specimens from the ancient sea that existed when Australia and Antarctica were one continent.”
The paleontologist was able to observe that the cooyoo had larger teeth than previously thought. It was believed they had small comb-like teeth in the upper jaw. The approximately 1-inch-long pointed teeth are more suited for gripping any struggling prey, including other fish, from the inland sea.
Local landowners, from the Proa Redclaw Farm, near Julia Creek, Duncan and Judy Fysh, invited representatives from Kronosaurus Korner in Richmond and students from RMIT University in Victoria to search for fossils on their property.
“We were out in the paddock when I heard a terrific scream—I thought that someone had been bitten by a snake. It turned out to be an excited paleontologist instead,” Mr Fysh said.
“I was looking at a spot where there’d been fossils found years before, and I was turning over these slabs of mud-stone, 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.”
“Cooyoo looked like the tarpon from hell, with a large underbite, giving it an exaggerated cartoonish appearance,” Dr Holland explains.
“It stretched over three meters in length, and had a powerful tail enabling rapid movement. Its only threats were large marine reptiles and sharks.”
According to The Guardian, 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 20 m 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.”