Rosa Rubicondior: Refuting Creationism - Science Fills A Whale Of A Gap

Wednesday, 13 August 2025

Refuting Creationism - Science Fills A Whale Of A Gap - No Gods Found

A cornucopia of tiny, bizarre whales used to live in Australian waters – here’s one of them - Museums Victoria

My last blog post concluded with:

Science moves forward by explaining these transitions; creationism survives only by ignoring them. With each gap that closes, their god has less room to hide, and the story of life becomes clearer without invoking the supernatural.

So, the prediction that more gap-closing transitional fossils would soon be found was hardly a bold one.

And sure enough, along comes just such a paper. To rub salt in creationists’ wounds, like the subject of my previous blog post on transitional penguin fossils, this one is also published by Oxford University Press in the Zoological Journal of the Linnean Society of London—the society to which Darwin and Wallace presented their ground-breaking 1858 papers On the Tendency of Species to Form Varieties, or, to put it another way, On the Origin of Species.

This new paper fills an important gap in the evolution of whales. It was written by Erich Fitzgerald of Museums Victoria Research Institute, Ruairidh Duncan of Monash University, Victoria, Australia, and colleagues. The discovery and its significance are explained in an article in The Conversation by Erich Fitzgerald and Ruairidh Duncan. Their article is reproduced here under a Creative Commons License, reformatted for stylistic consistency.

First, a brief background on the evolution of whales:

The Evolutionary Origins of Whales. Whales (order Cetacea) evolved from land-dwelling, hoofed mammals in the artiodactyl group, making them close relatives of modern hippos. Fossil and genetic evidence traces this transition over about 10–15 million years during the early to middle Eocene (roughly 50–40 million years ago).

Key stages include:

Pakicetids (~50 Ma): Early amphibious ancestors found in Pakistan; looked like wolf-sized mammals but with inner ear structures adapted for hearing underwater.
Ambulocetids (~49 Ma): Crocodile-like “walking whales” capable of swimming and walking on land, with limb bones adapted to both.
Remingtonocetids (~48 Ma): More streamlined bodies, reduced limbs, and increased adaptation to aquatic life.
Protocetids (~47–41 Ma): Fully aquatic breeders, though some may still have hauled out onto land; nostrils beginning to migrate up the snout.
Basilosaurids (~41–34 Ma): Fully aquatic whales with tiny, vestigial hind limbs and tail flukes; direct ancestors of modern whales.

Molecular studies show whales and hippos share a common ancestor that lived about 55 million years ago. The gradual shift from land to water is one of the clearest examples of macroevolution in the fossil record, supported by dozens of well-dated transitional forms.

A cornucopia of tiny, bizarre whales used to live in Australian waters – here’s one of them

Art by Ruairidh Duncan

Erich Fitzgerald, Museums Victoria Research Institute and Ruairidh Duncan, Monash University

Australia is home to a unique bunch of native land mammals, such as koalas, wombats and wallabies. These furballs evolved in isolation on this island continent and have become Australian symbols.

But between 27 and 23 million years ago, the coastal seas of Australia were also home to sea mammals found almost nowhere else: whales.

But not just any old whales. These creatures were among the strangest of all whales, called mammalodontids. If alive today, mammalodontids would be as iconically Australian as kangaroos.

Recent fossil discoveries from coastal Victoria reveal that not just one or two species, but a cornucopia of these wonderfully weird whales once called Australia home.

Our latest find, a roughly 25-million-year-old fossil of a newly named whale species Janjucetus dullardi, joins their bizarre ranks. Our discovery is published today in the Zoological Journal of the Linnean Society.
Baleen whales without baleen

Today, some of the most iconic whale species, such as blue and humpback whales, are baleen whales. These ocean giants use hair-like structures in their mouths, called baleen, to filter plankton – their main food source.

By contrast, mammalodontids were small-bodied (no longer than three metres), big-eyed, and had short jaws lined with teeth. Despite this description, we know that mammalodontids were, in fact, baleen whales … that lacked baleen. They were like an offshoot from the main evolutionary branch leading to today’s toothless giants.

All mammalodontid fossils date from the late Oligocene epoch – 27 to 23 million years ago. And three out of four named species have been found on Victoria’s Surf Coast, south-east of Melbourne.

Mammalodontid whales of Jan Juc, Victoria.

Art by Ruairidh Duncan

The first mammalodontid was found in 1932, and in 1939 was given the name Mammalodon colliveri. It had blunt jaw bones with extensive blood and nerve supply for face and lip muscles. Curiously, the teeth were worn down to the gums, suggesting it fed by slurping prey (along with abrasive grit) from the seabed.

In 2006, local naturalist Staumn Hunder found the first fossil of a species later named after him, Janjucetus hunderi. This whale sported a robust triangular snout with sharp teeth and powerful jaw-closing muscles.

If Mammalodon’s skull proclaims “I’m a sucker”, the skull of Janjucetus screams “biter and ripper”. It’s about as heavy metal as whale skulls get, departing radically from those of all other whales.

Although Mammalodon colliveri and Janjucetus hunderi hint at a surprisingly wide range of lifestyles for mammalodontids, the details of exactly how and when they became so different from other whales remain murky.

Fossil skulls of mammalodontid whales from left to right: Mammalodon colliveri, Janjucetus dullardi, Janjucetus hunderi.

Tom Breakwell, Museums Victoria

A tiny new whale

In 2019, school principal Ross Dullard found a whale fossil eroding out of rocks along the coast at Jan Juc in Victoria.

Dullard donated his find to Museums Victoria, where it was painstakingly cleaned and repaired in the laboratory so we could study it.

The fossil skull of Janjucetus dullardi was found along the coast of Jan Juc in the south-east of Australia.

Art by Ruairidh Duncan, graphic by Erich Fitzgerald.

As we describe in our new paper, Dullard’s find is a mammalodontid like Janjucetus hunderi, yet with different enough teeth and ear bones to warrant the naming of a new species: Janjucetus dullardi.

Incomplete fusion between skull bones, minimal tooth wear, and open tooth root canals tell us the animal was not fully grown when it died, possibly being a juvenile.

Artist’s reconstruction of the complete skull of Janjucetus dullardi. Parts preserved in the fossil are white and light grey.

Art by Ruairidh Duncan.

But just how small was it?

Using an equation that takes into account measurements of skull width compared with the total length of whales, we predicted that Janjucetus dullardi was about two metres long – small enough to fit on a standard single bed.

This makes it the smallest fossil whale discovered in Australia, and perhaps the first fossil of a juvenile whale found here.

The newly described fossil whale Janjucetus dullardi (2 metres long) next to a modern fin whale (26 metres) and a human diver (2 metres).

Art by Ruairidh Duncan, graphic by Erich Fitzgerald.

A warm-water paradise

Janjucetus dullardi and its fellow mammalodontids lived during the Late Oligocene Warming, between 26 and 23 million years ago. The coastal waters of Victoria were as warm as those off present-day northeast New South Wales, and the sea level was higher.

Small, toothy whales clearly didn’t mind this long summer of balmy, sunlit waters: 80% of the dozens of whale fossils found in Victoria from that era are mammalodontids – mostly unnamed species. In contrast, rocks of the same age in New Zealand have yielded just one mammalodontid from a century of intensive fossil whale collecting.

Unfortunately, the mammalodontid paradise was lost. By about 22 million years ago, mammalodontids had gone extinct, no longer playing a part in the ongoing saga of baleen whale evolution. Global cooling at about 23 million years ago resulted in lower sea levels and the loss of the mammalodontids’ shallow coastal habitat.

Janjucetus dullardi calf and mother swimming through the shallow seas off Victoria, 25 million years ago.

Art by Ruairidh Duncan.

If we know how their story ends, the beginning is still a mystery. Our research on Janjucetus dullardi and its kin suggests mammalodontids must have originated long before the age of their oldest known fossils, maybe 34 million years ago.

We suspect that the cradle of their evolution was here, in splendid isolation off southern Australia – home of the mammalodontids.
Erich Fitzgerald, Senior Curator, Vertebrate Palaeontology, Museums Victoria Research Institute and Ruairidh Duncan, PhD Candidate, Palaeontology, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Published by The Conversation.
Open access. (CC BY 4.0)

For creationists, every new transitional fossil is like an uninvited guest at their “no transitional fossils” party—except the fossils keep turning up, smiling for the camera, and bringing friends. Their famous claim that such forms don’t exist has been mugged repeatedly by reality, yet somehow it staggers on, patched up with ever more inventive excuses.

Each discovery forces a tactical retreat. When a gap closes, they simply declare that the new fossil isn’t “really” transitional, or that the “true” gap is actually somewhere else—preferably far enough away that no scientist is likely to find it in their lifetime. When that fails, there’s always the “just another animal” fallback, or the tried-and-tested “must be a hoax” defence, offered without evidence but with plenty of indignation.

The mental gymnastics required to maintain this illusion are almost impressive. You have to admire the sheer determination it takes to redefine “transitional” so narrowly that no fossil could ever qualify, or to pretend that a perfectly placed, well-dated specimen doesn’t count because it hasn’t personally shaken your hand. It’s a performance of willful blindness in the face of accumulating evidence—a kind of intellectual contortionism where the goal is not to see how far your mind can stretch, but how tightly it can curl up to avoid the light.

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