Janjucetus dullardi

A few years in the making, but I can finally share the art for my first ever first-authored whale paper. In it, we name a new species of toothed baleen whale from 25-26 million years ago in southeast Australia: Janjucetus dullardi. This is only the fourth species of a group called mammalodontids (and the third named from Australia). It's also the first to be named in almost twenty years since the first species (Janjucetus hunderi) was named in 2006. 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—with the addition of referred specimens and new data from existing Australian mammalodontid species—into how whales in this group changed as they grew. We think this individual was just over 2 metres long when it perished—so, just about able to uncomfortably lie on a single bed.

The holotype specimen (NMV P256471) was discovered in 2019 by a member of the public for which the species is named: Ross Dullard. It was found in what we informally call unit 1 of the Jan Juc Marl, meaning this whale is well constrained in geologic time. Unit 1 has also produced other fossil material including spear toothed dolphins (waipatiids) and fish otoliths, which you can spot, I'm sure, in the painting (as well as the traditional Nessie). I also included a slightly different Janjucetus in the background as, unlike Janjucetus dullardi, it is less clear how old the holotype of Janjucetus hunderi is, with a temporal range that includes all four of the informal units of the Jan Juc Marl.

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. We don't really know what the earliest exemplars of this group looked like, and they may have an undocumented evolutionary history that spans back several more million years. But the discovery of the third Australian mammalodontid species suggests that whatever that history was, the nexus was to be found in the shallow oceans that once covered prehistoric Jan Juc.