The first fossils of a giant ancestor of the great white shark have been discovered in Victoria, Australia.
Philip Mullaly, a fossil enthusiast, was having a stroll down the beach at Victoria’s popular surf coast, when something caught his eye. Sticking out of a boulder was part of a shark tooth, perfectly preserved, and still shining after millions of years of preservation as a fossil.
Mullaly immediately recognised that these were an important scientific discovery, and contacted Erich Fitzgerald of Museums Victoria. After a preliminary examination, Fitzgerald then led a team on two further expeditions to the site at Jan Juc. There, they discovered more than 40 individual teeth within the original boulder of discovery, all coming from the same species.
They belonged to a now extinct species called Carcharocles angustidens, which has a common name, the Great Jagged Narrow-Toothed Shark. This mega-toothed shark species would have swum the ancient seas around Australia around 25 million years ago, during a time known as the Oligocene.
The first discoveries of this species date back to 1835, when it was named by the Swiss naturalist Louis Agassiz. He originally identified it as a prehistoric species of the modern great white shark, Carcharodon. However, in 1987, French shark expert Henri Cappetta recognised it as a distinct lineage, and named the new genus Carcharocles.
The collection of teeth were up to 7cm long, which is big for a shark. Previous discoveries of the same species from rocks in New Zealand were even bigger, at almost 10cm in length.Shark teeth are fairly common in the fossil record, being one of the only parts of a shark that usually preserves. This is because shark skeletons are made of cartilage, not bone, which is softer and more difficult to fossilise. Finding multiple teeth from the same shark is still a rare discovery though.
These teeth are of international significance, as they represent one of just three associated groupings of Carcharocles angustidens teeth in the world, and the very first set to ever be discovered in Australia. – Dr. Fitzgerald.
This species grew to more than 9m in length, which is far larger than the modern great white shark, and almost twice its length. It is thought that it would have even preyed on small whales around at the time, as well as penguins, dolphins and fish. The teeth of Carcharocles were very pointed, and had sharp serrations along the sides, perfect for gripping on to fleshy prey.
As well as the teeth of Carcharocles, the boulder also contained teeth from a small species, Hexanchus – the Sixgill shark, which still survives to this day off the coast of Victoria. The research team believes that these teeth come from several individual animals, which were scavenging on the huge carcass of the Carcharocles after it died and sunk to the sea floor. As they feasted, their teeth would have detached, which is not such a huge problem for sharks, which can rapidly regenerate lost teeth.
Mullaly has kindly donated the fossils to Museums Victoria’s collection, where they can be further studied and used for educational purposes. They will be unveiled to the public at the Melbourne Museum on 9th August as part of a Mega Shark Fossil Find display.