Ancient whale with razor-sharp teeth discovered in Australia

A newly identified species of ancient whale reveals how the first baleen relatives hunted, sensed their world, and grew. The compact predator, named Janjucetus dullardi, lived about 26 million years ago and combined big forward-facing eyes with slicing teeth.

The discovery offers a rare window into the early evolution of baleen whales, long before they became filter-feeding giants.

Scientists at Museums Victoria’s Research Institute have described the species from a partial skull found near Jan Juc on Wadawurrung Country along Victoria’s Surf Coast.

The fossil was discovered in 2019 by local resident Ross Dullard, who donated it to the museum; the species name honors his find.

Small predator with slicing teeth

Janjucetus dullardi was little more than two meters long. It looked nothing like the gentle titans that glide through oceans today. With a short snout, large forward-looking eyes, and razor-sharp, slicing teeth, it likely chased agile prey in warm, shallow seas.

The animal belongs to mammalodontids. These are early whale relatives restricted to the Oligocene, roughly 30 to 23 million years ago. This is the third mammalodontid from Victoria and only the fourth known worldwide. 

Unlike most finds, this specimen preserves both well-formed teeth and inner ear structures. Those features are crucial for decoding how early whales fed, heard, moved, and behaved.

Ancient specimen and whale evolution

The fossil is a partial skull with ear bones and teeth. Its journey began on a winter beach walk in June 2019. Recognizing its importance, Dullard turned it over to the museum, where specialists carefully prepared and studied it.

“This kind of public discovery and its reporting to the museum is vital,” said senior author Erich Fitzgerald, a curator of vertebrate palaeontology at Museums Victoria Research Institute. 

“Ross’ discovery has unlocked an entire chapter of whale evolution we’ve never seen before. It’s a reminder that world-changing fossils can be found in your own backyard.”

MicroCT scans mapped the internal passages of the ear region, including the cochlea. Those delicate structures help scientists infer hearing range and sound processing. 

In predators, hearing cues support navigation, prey detection, and communication. Here, they add new data on how early baleen relatives sensed their environment.

“This fossil opens a window into how ancient whales grew and changed, and how evolution shaped their bodies as they adapted to life in the sea,” Fitzgerald said.

Shark-like cousin of baleen whales

The study identifies the specimen as a juvenile, just over two meters long. Its anatomy points to fast, visually guided hunting rather than filter feeding. The big eyes suggest high reliance on sight. The slicing dentition indicates grasping and cutting prey.

“It’s essentially a little whale with big eyes and a mouth full of sharp, slicing teeth,” said lead author Ruairidh Duncan, a PhD student 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.’

Because the inner ear is preserved in detail, researchers can test ideas about how these early whales tracked sound and balanced during quick maneuvers.

Teeth plus ear anatomy in one juvenile skull is rare. Together, they allow fine-grained comparisons with other early whales and with living baleen species.

Ancient whales in warm oceans

The fossil comes from the Jan Juc Formation, deposited during a time of global warmth and rising seas. Southern Australia is emerging as a key stage for early whale evolution. Repeated discoveries from this coast are building a picture of experimentation and transition in whale anatomy.

“This region was once a cradle for some of the most unusual whales in history, and we’re only just beginning to uncover their stories,” Fitzgerald said.

The setting matters for today as well. Ancient whales that thrived in warmer oceans provide clues to how marine life responds when seas heat up. Anatomy, behavior, and distribution can all shift. Fossils like Janjucetus dullardi help calibrate those responses across deep time.

“We’re entering a new phase of discovery,” Fitzgerald said. “This region is rewriting the story of how whales came to rule the oceans, with some surprising plot twists!”

Contributions to evolutionary research

Each new specimen can reframe long-standing evolutionary questions, especially when it preserves rarely seen structures.

“The findings demonstrate the power of our collections to unlock stories that change the way we understand life on Earth,” said Lynley Crosswell, the CEO and Director of Museums Victoria. 

“Thanks to the generosity of the public and the expertise of our scientists, Museums Victoria Research Institute is making globally significant contributions to evolutionary research. Discoveries like Janjucetus dullardi remind us that our collections are not just about the past – they’re shaping the future of science.”

Teams continue to survey Victoria’s coastline. They are also re-examining older specimens in the Museums Victoria State Collection with fresh tools and questions. The expectation is simple.

More fossils are out there. Some are already sitting in drawers. Together, they promise to sharpen the narrative of how small, sharp-toothed hunters gave rise to the largest animals that have ever lived.

The study is published in the Zoological Journal of the Linnean Society.

Image Credit: Artwork by Ruairidh Duncan. Source – Museums Victoria

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