Welcome back to the Deep Dive. Today we are cracking
open a cold case file from the prehistoric world.
We're heading down underway, way down under,
both in latitude and in time, to look at a creature
with a name that, I have to be honest, sounds
less like a scientific classification and more
like a comic book supervillain. Or a really expensive
piece of gaming hardware. Ultrastenos. Ultrastenos.
It just sounds intense, doesn't it? Prepare to
face the wrath of Ultrastenos. But as we've been
combing through the source material for this
dive, specifically some incredible detective
work from the Queensland Museum involving researchers
like Paul Willis, Adam Yates, and Michael Stein,
it turns out this animal is actually a perfect
case study in how messy paleontology really is.
It really is. I mean, we tend to think of fossils
as these immutable truths. You dig up a bone,
you know what the animal looked like, end of
story. But this story is all about... mistaken
identity. It's about how we interpret broken
fragments, how gravity and time can literally
warp reality, and how a creature underwent this
massive makeover. It went from being described
as this needle -nosed, gharial -like specialist
to something completely different, all because
of how we interpret fractures and fossils. The
total makeover story. But before we get to the
twist, we need to ground ourselves. We are in
the late Ligocene period. roughly, what, 28 to
23 million years ago. Geographically, we're in
northwestern Queensland, Australia, in the Riversley
World Heritage Area. Now, I know Riversley is
legendary in fossil circles, but set the scene
for us. This isn't the dusty red outback we see
in Mad Max. Oh, far from it. If you go to Riversley
today, it's all spine -effects grass and blistering
heat. But back in the oligocene, this was a lush,
dynamic environment. We're talking about a karst
landscape. So think limestone, porous rock full
of holes, caves, and underground drainage systems.
On the surface, you had open forests, but the
water system was unique. It wasn't necessarily
these massive, flowing river deltas like the
Amazon. It was likely a system of forest lakes
and ponds that were really rich in lime. And
that lime is key, right? Because chemistry is
kind of the unsung hero of paleontology. Absolutely.
Limeridge water is basically a fossil factory.
It coats the bones in calcium carbonate, essentially
turning them into rock very quickly before they
can rot away. That's why Riversley is one of
the most important fossil sites on Earth. It
preserves things that usually just disappear.
And swimming in those limeridge ponds was the
subject of our deep dive. So our mission today
isn't just to list facts about a dead crocodile.
We want to understand the detective work. We
want to see how mistakes happen, how they get
fixed, and, this is the crazy part, how two completely
different fossil discoveries, separated by decades,
turned out to be the exact same animal. That
is the aha moment we're building towards. Let's
get into the timeline, because this really does
play out like a mystery novel. Section 1. A Tale
of Two Fossils. The story really kicks off in
1997. Right. In 1997, paleontologist Paul Willis
is working at a spot in Riversley with the evocative
name of the White Hunter site. I love the site
names at Riversley, White Hunter, Low Lion. It
just adds to that adventure vibe. It does. So
at White Hunter, Willis finds a snout, just the
front end of the animal. Now, looking at this
snout, he sees it's heavy, it's robust, it looks
like it's built for taking a beating. And based
on that heaviness, he connected to a known group
of Australian crocs called Baru. And Baru isn't
exactly a delicate flower, is it? Not at all.
Baru is often called the cleaver -headed crocodile.
I mean, imagine a crocodile with a head shaped
like a sledgehammer. Very heavy, very dangerous,
massive crushing power. Willis thinks this new
snout looks like a cousin of Garu, so he names
it Baru Hooberry. Okay, so we have finding number
one. Baru Hooberry. Heavy -built, typical crocodile
vibe. But the sources mentioned there were other
pieces found nearby that didn't quite fit the
puzzle. Yes, and this is where the messiness
of the field comes in. At that same site, they
found some skull tables, you know, the flat top
part of the head behind the eyes. They were found
near the snout, but they didn't site together.
There was missing bone in between. So as a scientist,
Willis couldn't ethically say these definitely
belong to the same animal. They just remained
mystery pieces, just sitting in a museum drawer,
labeled but unassigned. Waiting for their moment.
Okay, fast forward almost 20 years. It's 2016.
A different team, led by Michael Stein, is working
at a different location, the Low Lion site. And
they strike gold. They find a back of the skull
and a lower jaw, a mandible. But when they look
at this jaw, they see something shocking. The
jawbones, they seem to converge really rapidly.
They angle inward sharply, suggesting that the
snout of this animal was incredibly long and
thin. Like a pair of needle nose pliers or like
those gharials you see in India. Exactly. A specialized
pin thin snout. It looked so radically narrower
than anything else found in Australia that they
decided it needed a name to reflect that extreme
anatomy. They combined the Latin ultra, meaning
extreme, and the Greek stenos, meaning narrow.
Ultrastinos, extreme narrow. And they named the
species Ultrastinos willisi, honoring Paul Willis,
ironically enough. So as of 2016, the scientific
consensus was that we had two different animals.
We had Bobby Hoobury from 1997, which was a heavy
-duty cruncher, and Ultrastinos willisi from
2016, which was this delicate, needle -nosed
fish snatcher. Two different animals, two different
ecological niches. One crushes, one snatches.
That was the picture. Until 2024? This is where
the plot twist happens. Adam Yates and Michael
Stein publish a breakthrough paper. They decide
to do some housekeeping on the collections and
take a closer look at those old mystery pieces
from 1997. Specifically, that skull fragment
Willis had found but couldn't place. They took
that piece and they took the original Baru -Huberi
snout and they tried to fit them together again.
It wasn't just a maybe. It was a lock. The edges
were parallel. It turns out there was a fracture
where the bone had broken apart, probably due
to erosion or weathering before it was even collected.
When you put them together, it wasn't just two
animals of the same species. It was likely the
same individual animal. That is just statistically
wild. Yeah. I mean, think about the odds. You
dig up a snout. Then decades later, you realize
the back of the head was sitting in a drawer
the whole time. It's the paleontological equivalent
of finding the other sock in the dryer 20 years
later. But this created a domino effect. Once
they had the whole skull reconstructed, they
could look at the ornamentation, the bumps and
ridges on the bone. And guess what? That ornamentation
matched the 2016 Ultrastinos finds perfectly.
So Baru Huberi and Ultrastinos Willisi are the
same animal. One and the same? But wait, they
have different names. One is Baru, one is Ultrastinos,
one is Huberi, one is Willisi. How do you decide
what to call it? It sounds like a legal nightmare.
It's less legal and more bureaucratic. We have
to consult the rulebook, the International Code
of Zoological Nomenclature. The core rule is
generally priority. The first name published
wins. So Huberi wins because it was from 1997.
The species name Huberi wins, yes. But the genus
name Baru was incorrect because this animal clearly
wasn't a Baru. It was distinct enough to deserve
its own genus. So the valid genus name is Ultrastanos,
which was coined in 2016. So you just mash them
together? You get Ultrastanos Huberi. And Ultrastanos
Willisi. It becomes a junior synonym. It's essentially
invalid now. It's a ghost name in the history
books. But okay, we have a name. Ultrastanos
Huberi. But this creates a huge problem, doesn't
it? As we established, the name Ultrascanos means
extreme narrow. Correct. But the 1997 snout,
the hubiri part, was described as broad and short.
And the 2016 jaw was described as extreme narrow.
If they're the same animal, how can it be both
broad and narrow? Did it have a shape -shifting
face? And this is what we call the Pinocchio
problem, or maybe the reverse Pinocchio. The
name describes a feature the animal literally
did not have. And this is where the science gets
really interesting because it's about taphonomy,
the study of how organisms decay and become fossilized.
Let's dive into that because looking at a jaw
and thinking it's needle thin when it's actually
broad, that seems like a massive miss by the
2016 team. How did that happen? Well, it comes
down to the condition of the fossil. The 2016
mandible, the lower jaw was broken. It wasn't
attached to the skull. And crucially, the left
jawbone was bent inward significantly more than
the right one. Ah, so it was warped. Exactly.
We call it plastic deformation. I mean, think
about it. These bones are sitting in the ground
for 25 million years. Rocks shift. pressure builds
up. Even stone can warp if you give it enough
time and pressure. It's like leaving a vinyl
record in a hot car. It's still the record, but
the shape changes. That's a great analogy. So
the bone was kind of melted inward. In a geological
sense, yeah. And when the researchers in 2016
reconstructed it, that inward bend created an
optical illusion. If you followed the angle of
the bent bone, it looked like the jaws were converging
into a super thin point. But in the 2024 revision,
Yates and Stein realized that if you digitally
unwarp, that bone rotated back to its natural
position, it doesn't make a needle shape, it
makes a U shape. So Ultrastinos, the extreme
narrow crocodile, actually had a short, flat
face. Ironically, yes. It was Platyrostral, flat
-snouted, and Brevira strain, short -snouted.
The name is now a permanent misnomer. It's named
for a feature it never actually had. That is
fantastic. It's like naming a dog spot and then
realizing it has stripes. But surely the shape
of the jaw isn't the only clue. If I'm trying
to figure out what a crocodile eats, I'm looking
at the teeth. And the teeth tell the real story
here. This is why the long snout theory should
have been suspicious from the start. Think about
what a long -snouted crocodile eats. Gharials,
for example. They are specialized fish traps.
Right. They sweep that long, thin head through
the water sideways to catch fast prey. Speed
is key. And to catch a slippery, fast -moving
fish, you need teeth that act like a cage. You
need long, needle -like, interlocking teeth.
Snap, and the fish is pinned. In ultrastinos.
It didn't have needle teeth, it had malaria -formed
teeth. Malaria -formed, like our molars. Similar
function. They were low, rounded, and robust
buttons of bone. These aren't for piercing, they
are for crushing. If you tried to catch a fast
-moving fish with these teeth, it would just
slip out like a wet bar of soap. These teeth
are built for high pressure. They are built to
crunch through shells, bones, and armor. So we
have a short -faced, crunching crocodile. Paint
a picture for me. What did this thing look like
when it was alive? Was it big? Surprisingly small.
We're talking about 1 .5 meters, maybe 5 feet
long. Similar in size to a modern Australian
freshwater crocodile. So relatively cute -sized.
Relatively. And it had some distinct features.
The nostrils were right at the tip of the snout,
facing slightly forward. And the eyes, this is
interesting, it had very large teardrop -shaped
openings on top of the skull called supratemporal
fenestri. Teardrop eyes. Sounds poetic, but I
assume those holes are for muscles. Exactly.
The fact that those openings were so huge suggests
massive jaw muscles. This animal had a very powerful
bite for its size. And the jawline wasn't straight.
It had... Fistoons? Fistoons. Like party decorations.
Like waves. The tooth row curved up and down,
which again helps with holding onto prey that
you're trying to crush. It creates locking points
so the hard shell doesn't slide out. Okay, so
we have a clear avatar now. Small, five -foot,
short -faced, muscle -headed crocodile with crushing
teeth. Let's talk about its life. You mentioned
Riversley wasn't a desert then, but it wasn't
exactly a massive river delta either. No, the
low lion site where the 2016 fossil was found
was likely open forest. It was a karst system,
lakes and ponds that drained through limestone.
And these water bodies might not have been permanent.
Exactly. Like modern freshwater crocs, Ultrastinos
might have had to deal with water levels dropping
or ponds drying up seasonally. It had to be adaptable.
It wasn't alone, right? I imagine 25 million
years ago. Australia had some scary wildlife.
Oh, absolutely. Ultrastinos was living alongside
giants. At the White Hunter site, it coexisted
with Baru Wikene. That's the real Baru. The real
deal. And Baru Wikene was massive, heavily built,
a top predator. If Ultrastinos is a compact car...
Baru is a semi -truck. So how does a five -foot
Ultrastinos survive next to a Jai Baru? Niche
partitioning. Basically staying out of the way
and eating different things. Ultrastinos was
the underdog. It was small enough to hide in
the shallows or the denser vegetation where the
big Baru couldn't go. And the diet. You said
it wasn't eating vats because of those crushing
teeth. That's the current theory. Originally,
when they thought it had a long snout, they assumed
it was a piscivore, a fish eater. But now...
With the short snout and crushing teeth, plus
the fact that fish fossils are actually surprisingly
rare in that specific part of Riversley for that
time period. Wait, rare fish fossils? In a lake
system? That seems counterintuitive. It does
happen. Sometimes the chemistry doesn't preserve
them, or maybe the ponds were isolated and seasonal,
so fish populations just couldn't get established.
But because of the teeth and that scarcity, the
new theory is that Ultrastinos was eating small
land animals. Frogs, snakes, birds, maybe small
mammals. Crunchy snacks. Exactly. Snails, crustaceans,
anything it could grab and crush. This brings
up a really fascinating point that the source
has highlighted. It's what they call the implications
for mecosuchinae. And this leads us to the mystery
of the ghost niche. I love this concept. So mecosuchinae
is the group Ultrastinos belongs to. It's a specific
group of extinct crocodiles from Australia and
the South Pacific. And here's the weird thing.
Unlike croc families in the rest of the world,
Mekosuchines never really evolved that classic,
long -snouted, gharial -like shape. Which is
strange, right, because if you look at South
America, Africa, indialong snouts pop up everywhere.
It's a great design for catching fish. It's a
very successful design. Convergent evolution
usually makes it happen. But in Australia, nothing.
And Ultracinos was supposed to be the answer.
It was supposed to be the missing link that proved
Australian Crocs did do it. Exactly. It was the
one exception. But now that we know Ultrastinos
actually had a short snout, well, the exception
is gone. The mystery is back. Why not? Is there
something about Australia that just hates long
snouts? There are a few theories. One is developmental
constraints. Maybe their genes just wouldn't
allow that shake to form easily, similar to how
modern alligators rarely get super narrow snouts.
But the more compelling theory ties back to the
environment. The drying continent. Exactly. If
the water bodies in Australia were becoming more
seasonal, drying up into mud puddles every year,
being a specialized fish eater is a risky strategy.
If the fill die out when the pond shrinks, you
starve. So you need to be a generalist. You need
to be a Swiss army knife, not a scalpel. Precisely.
If you have a short, broad snout, you can eat
a fish if you find one, but you can also eat
a wallaby or a frog or a snail. You survive the
bad times. So maybe the Australian landscape
itself forced these crocodiles to stay generalists.
It's the ghost of a niche that nobody could afford
to fill. That is such a cool concept. It frames
evolution not just as what is the best design,
but what is the safest bet. And in Australia,
the safe bet is usually adaptability. Let's quickly
look at the family reunion before we wrap up.
We established it's a Mekosushin. Is it related
to the modern saltwater crocs we see in Darwin
today? No, and that's a common misconception.
The salties and freshies in Australia today are
relatively new arrivals, immigrants from Asia
that came over in the last few million years.
Ultrastinos and its kin are the original Australians.
They were there for tens of millions of years
before the modern crocs showed up. And despite
the old name Baru Huberi, It's not closely related
to the giant Baru, right? No, they are distant
cousins within the Mecosuchin group. Ultrastinos
sits on a different branch. It's actually closely
related to a creature we haven't even officially
named yet, referred to in the papers as the Bullet
Creek taxon. The Bullet Creek taxon sounds like
an X -file. It does, and it's also on the branch
with the dwarf Mecosuchins, animals like Trilophosuchus
and Mecosuchus. Trilophosuchus is that tiny land
croc, right? The one that looked like a little
lizard. That's the one. So Ultrastinos confirms
that there was this distinct lineage of small
-bodied, short -snouted crocs evolving right
alongside the giants. They weren't just baby
giants. They were their own thing, doing their
own evolutionary experiment. So what does this
all mean? We've gone from a comic book villain
name to a tale of two fossils, a glue job that
solved a 20 -year cold case, and a total anatomical
re -imaging. I think the biggest takeaway is
scientific humility. The name Ultrastinos, extreme
narrow, will likely stay. It's the official valid
name. But it describes a feature the animal didn't
have. It is a permanent, Latinized reminder that
we can get things wrong. It's honest, though.
It is. It shows science working as intended.
New evidence comes to light. In this case, Yates
and Stein realizing those fractures matched,
and we correct the old assumptions. We don't
stick to the old idea just because we liked the
name or the cool factor of a long snout. And
it reminds us that saucels aren't just rocks.
They were living things that broke, decayed,
and got squished over millions of years. Reconstructing
them is really hard work. It's a 3D puzzle where
half the pieces are missing and the ones you
have are bent. Before we wrap up, I want to leave
you with a final thought on that ghost niche.
Long -snouted crocodiles appear almost everywhere
else in the world. They are efficient, but not
here. Not here. If Ultrastinos wasn't the one
and the Mecasuchines never did it, is there something
about the Australian landscape itself that is
fundamentally hostile to specialization? Is the
hydrology of the continent, the way the water
flows and dries up, so harsh that becoming a
specialized fish eater is a death sentence? It's
a fascinating question. Did the drying of the
continent kill off the potential for that lifestyle
before it could even start? Or is there a fossil
out there, still waiting in a limestone block
at Riversley, that will prove us wrong again?
Maybe we'll find the real Ultrastinos one day.
But for now, we have Ultrastinos Uberi. The short
-snotted crocodile with the ironically extreme
name. A small croc with a big story. Thanks for
diving deep with us. Keep questioning what you
see in the museums. Sometimes the labels only
have the story. See you next time. Catch you
on the next deep dive.