“Small and deceptively cute, but definitely not harmless” is how scientists have described a new species of ancient whale, from a 25-million-year-old fossil found on Victoria’s surf coast.
This early species, called Janjucetus dullardi, was an extremely unusual animal, said Dr Erich Fitzgerald, senior curator of vertebrate palaeontology at Museums Victoria Research Institute.
It was tiny – about the size of a dolphin – and had razor-sharp teeth, bearing little resemblance to its closest living relatives in the baleen whale family, including blue whales, some of the largest animals to ever live.
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The whale’s heavily built skull was “almost over-engineered”, Fitzgerald said. It had relatively large eyes – approaching the size of tennis balls – and a short snout with deeply rooted teeth for gripping and tearing.
“This was a really gnarly whale that I personally wouldn’t want to get in the water with,” Fitzgerald said.
“It’s essentially a little whale with big eyes and a mouth full of sharp, slicing teeth,” said co-author Ruairidh Duncan, a researcher at the Museums Victoria Research Institute and Monash University. “Imagine the shark-like version of a baleen whale – small and deceptively cute, but definitely not harmless.”
Duncan and Fitzgerald described the new species in the Zoological Journal of the Linnean Society from an “exceedingly rare” fossil find that included a partial skull, ear bone and eight teeth – key features that enabled the scientists to identify it as a new species.
When fully grown, the species was probably about 3m long. But the fossil was most likely a juvenile, based on its wide open root canals, barely worn teeth and bone connections that were not as tightly fused as in a mature specimen. “This individual was probably no more than about two to 2.2m long,” Fitzgerald said. “You could fit it on to a beach towel.”
Janjucetus dullardi lived during the Oligocene (30-23 million years ago) – about halfway back to the extinction of the dinosaurs – a time of global warmth and rising seas. It was the fourth known species from a group known as mammalodontids, unusual animals that were an “early offshoot” of the baleen whale family tree, Fitzgerald said.
Dr Erich Fitzgerald with the teeth and partial fossil skull of Janjucetus dullardi. Photograph: Tom Breakwell/Museums Victoria
He said evidence from fossils of tiny plankton from the Jan Juc Formation – the same kind of rock – suggested sea temperatures in southern Australia would have been warmer then, more akin to subtropical waters off Coffs Harbour.
“In these seas, there was this extraordinary abundance of life, including all these little whales, giant penguins, sharks – about a third, or even twice as long as today’s great white shark – and various other primitive dolphins and other species of whales. It was a very different world,” Fitzgerald said.
It was a turning point in the history of life in the oceans, and the beginning of an explosion in the diversification of whales and dolphins.
Flinders University palaeontologist Prof John Long, who was not involved in the paper, said the fossil was a remarkable find that could help uncover the evolutionary steps as early carnivorous whales transitioned to become filter feeders.
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“To understand the radiation and evolution of the big baleen whales that live today, we need to look at the fossil record to see the stages of how they acquired their special characters,” he said.
It also highlighted the value of fieldwork, by professional scientists and members of the public, Long said.
The discovery wouldn’t have been possible without local resident and school principal Ross Dullard, who found the specimen in 2019 while walking along the beach near Jan Juc on Victoria’s surf coast.
Recognising the fossil’s significance, Dullard donated the fossil to the museum for further study. In recognition of his contribution, the new species was named in his honour.
This highlighted the critical role that members of the public continued to play in Australian palaeontology, Fitzgerald said. “It’s a reminder that world-changing fossils can be found in your own back yard.”
“Victoria has got a rich fossil heritage,” said Long. “I grew up in Melbourne and collected fossils as a kid since I was seven. You can find fossils of nearly all geological periods in Victoria … if you know where to look.”
