On a windswept stretch of Victoria’s Surf Coast, fossil hunters have pulled a startling creature from the past. A tiny whale (relatively speaking) with razor teeth and huge eyes (again, relatively speaking) from 26 million years ago.
Newly described Janjucetus dullardi is a pint-sized predator cousin of today’s gargantuan baleen whales. Modern baleen whales are the largest animals that have ever lived. Think blue whales, which can reach 30 metres, and weigh a hundred tons.
Even though it is much smaller, it is related to modern baleen whales
J. dullardi does not resemble the leviathan Blue Whale, at least not in size. Further, it has several predator-like features, such as harp, slicing teeth and a shark-like snout, according to the paper published this month that names and describes the species. Nevertheless, its skull carries an identifying connection to baleen whales.
Dentition of Janjucetus dullardi (NMV P256471) in lingual, buccal, basal (for right P2, P3, and M1), and mesial (for right M1 and p4) views. Zoomed in section shows lingual abrasive tooth wear of M1. The white lines on the basal views denote the boundaries of the open pulp cavities. Tooth positions are approximate and based on comparison with Janjucetus hunderi (NMV P216929). Image credit: Ruairidh J Duncan et al.
A bulbous knob on the braincase floor that confirms its place among early baleen whales. This is diagnostic, and is found in all early baleen whales, even before they developed modern baleen whale traits like filter-feeding or the massive bulk.
J. dullardi is the third such whale found in Victoria, and the fourth in the world. It belongs to the ancient mammalodontid family. Mammalodontid are a family of toothed whales within the group of baleen whales (or mysticeti) . The described specimen preserves both teeth and delicate ear bones, it can tell us how early whales heard, swam, and fed.
“As well as showing different ear bone characteristics and different (and largely unworn!) tooth anatomy, Janjucetus dullardi is unique amongst mammalodontids for its clearly immature stage of growth, permitting insights into how whales in this group changed as they grew.”, Ruairidh Duncan explained, on X. “Mammalodontids are perhaps one of the weirdest groups of whales ever discovered. Janjucetus is especially so, with complex, razor-sharp teeth, gigantic eyes and short, stubby snouts. They have an evolutionary history that likely spans back several more million years.”
A different world
Victoria’s Oligocene (~26 million years ago) seas were much warmer than today. And they offered a haven for these early whales. “By the Oligocene epoch (33.9–23.03 Mya), filter-feeding baleen whales were diversifying alongside a plethora of more archaic [baleen whales] that possessed functional teeth.” wrote Ruairidh J Duncan et al.
Unlike other regions, where mammalodontids are rare, here this group dominates the whale fossil record. In fact, more than 80% of Oligocene whales from this region are mammalodontid.
In 2019, school principal and amateur fossil hunter, Ross Dullard, stumbled upon the whale fossils. He found a partial skull, ear bones, and razor-sharp teeth embedded in the Jan Juc Marl. Recognizing its importance, he donated it to Museums Victoria. He has been honoured with the species name.