Thread 5066650

Nanotyrannus is real
https://twitter-thread.com/t/1983926921898660347

>>5066650 (OP)
I ain't clicking that shit

>>5066651
>It's real.

>And it's spectacular.

>Sometimes, one fossil really can change everything you think you know. NEW PAPER (see bottom of thread) AND [THREAD]

>For paleontologists and dinofans, Nanotyrannus needs no introduction. This unassuming little skull is the unlikely focus of the most infamous debate in paleontology. Is it its own species? Or is it a young T. rex? It seems like a simple question - but its been very hard to solve.

>I won't go into the background of the debate here - it's much too long! Suffice it to say, paleontologists have argued for decades about whether Nanotyrannus is a real dinosaur or not - and the debate has often been acrimonious.

>But the consensus was, until today, that these small theropod dinosaurs are T. rex teenagers. And this has become a foundational assumption in many, many studies on T. rex and how it lived, evolved, and grew.

>But today, in our new paper, Dr. Lindsay Zanno and I have shown that science got this one wrong. Nanotyrannus was not the juvenile form of T. rex - it was its own species of sleek, speedy predator that lived alongside T. rex at the twilight of the Age of Dinosaurs.

>How did we prove it? The right combination of an exceptional new fossil - the Dueling Dinosaurs tyrannosaur - and laser-focused science, using multiple lines of evidence to test different hypotheses and lead us to the truth.

>The Dueling Dinosaurs are a pair of exceptionally preserved dinosaurs - a Triceratops and, as we now know, a Nanotyrannus. The Nano is spectacularly complete - 100% complete. Every bone of its body is present - and those bones brought new data to an old debate.

>For one, its hands! The hands of Nanotyrannus had never been discovered before the DD Nano. They're huge! Some bones are twice as long as the same bones in T. rex. The claws are enormous and hooked, and the finger bones have well-developed muscle attachment sites.

>>5066667
>We think Nanotyrannus still used its hands for hunting, at least a little. But they do show a sign of the evolutionary arm reduction that defined other tyrannosaur species - a vestigial third finger, represented only by a single finger bone.

>T. rex famously only had two fingers, but Nanotyrannus technically still had three. Bones don't shrink or vanish during growth - so the huge hands and "bonus" finger of the DD Nano showed us clearly that the animal couldn't be a young T. rex.

>Second, Nanotyrannus has features of its skull that do not change during growth in other tyrannosaurs, and which we think *cannot* change during growth in any reptile. For instance, Nanotyrannus famously has a sinus in the quadratojugal bone...

>...which would need to vanish during growth if it's T. rex. If anything, sinuses get *bigger* during growth! And my PhD work on living crocodylians showed that presence or absence of sinuses in particular bones is useful for species identification, even for tiny hatchlings.

>Nanotyrannus also has way more teeth in its jaws - up to 17 in the DD skull, and as few as 15. T. rex never has more than 12 teeth. Despite many claims to the contrary, tyrannosaurs do not lose teeth as they grow...

>For instance, Gorgosaurus shows consistent variation between 13 and 15 teeth maxillary teeth, and Tarbosaurus adults have 13 maxillary teeth, just like the adorable 3 year old baby Tarbosaurus that was described in 2011. Tooth # is individually, not ontogenetically, variable.

>In 1999, Thomas Carr justified tyrannosaur tooth loss with crocodylians, which he said lost teeth during growth too. But they don't. My own work on alligators found no evidence of growth-related tooth loss, and the studies Carr cited actually don't support his claim...

>>5066668
>They're talking about a very particular circumstance, where overgrowth of a tooth from the lower jaw erodes away and destroys the socket for a tooth at the tip of the snout. It's common - but it's not a seamless reduction in the number of teeth.

>And again, tooth count is set by birth - in fact, long *before* birth. The cell populations that eventually form tooth sockets in the jaws are there before the jaws themselves, and there's just no evidence for some positions closing up in any living or extinct animal.

>Some very odd theropods, distantly related to tyrannosaurs, did entirely replace their teeth with beaks during growth. But even in these species, we can see an internal canal in the jaws marking where the tooth roots had been.

>So far, all of the evidence was against these two being the same species. The required growth changes were biologically impossible, at least according to our understanding of how development works, and what was seen in close relatives of T. rex.

>But in modern systematics, we identify species by the presence of unique, derived features called apomorphies, which show common ancestry. So we also needed to see if Nanotyrannus did have unique traits that it shared only with T. rex.

>If it did, it would be evidence that they were either the same species, or very close relatives. Carr (1999) had said that there were 13 of these traits, but Currie (2003) showed that 12 of these were actually not unique to T. rex and Nanotyrannus...

>...and Lindsay and I showed that the last one was also flawed. T. rex and Nano both have very wide skulls, but the "width" is not directly comparable. In T. rex, the skull is very wide, and is over 1/2 the length of the skull. In Nano, the skull width is less than 1/2 its length.

>>5066669
>So this isn't an apomorphy - it's convergent evolution. As we continued our work, we found that Nanotyrannus lacked *any* diagnostic trait of T. rex. Without apomorphies, there's no scientific justification to think these animals are the same species.

>And finally, the growth record. I'll keep it short and sweet - the Dueling Dinosaurs tyrannosaur was an adult when it died. And an accessory sinus in its palatine bone, shared only with the Nano type specimen, is the apomorphy we needed to identify it as an adult Nanotyrannus.

>So we had a dinosaur that had no features that said it was T. rex, could not have changed during growth to look like T. rex, and was an adult that was done growing at the moment of its death. There was simply no possible way for it to be a juvenile T. rex.

>But there was one more fun wrinkle. We found that the Nanotyrannus specimen "Jane" was different, in many ways, from the DD Nano and the Nano type specimen. We had trouble believing it at first, but the conclusion was inescapable - it was another species!

>Jane has been the focus of the Nano debate for years, and we recognized that it would always carry baggage of its controversy. So we gave it a name that symbolically washed all of that history away. Meet Nanotyrannus lethaeus - named for the River Lethe of Greco-Roman mythology.

>Jane is from the Hell Creek Formation, so a river of the mythological underworld was fitting - but even more so because in the Aeneid, Vergil presents the Lethe as the river that souls drink from to forget their past lives and be reincarnated. We thought it was fitting.

>Nanotyrannus lethaeus seems to have been a larger dinosaur than Nanotyrannus lancensis - even though Jane was not mature when she died, she was already slightly larger than the Dueling Dinosaurs specimen. We estimate that she could have gotten to be noticeably larger.

>>5066670
>We created a new phylogenetic data matrix to figure out the interrelationships of tyrannosaurs, and found that Nanotyrannus is a member of a very early-diverging group of tyrannosaurs.

>One of our analyses painted an even more intriguing idea - that Nanotyrannus had its ancestry in the Eastern half of North America, and migrated into T. rex's territory as sea level fell and reconnected the two halves of the continent. But we can't yet test this idea further.

>As a proud out-of-touch East Coaster, I would love for Nanotyrannus to have originated here. But we need to do a lot more science to know for sure - and wait for the discovery of better fossils of East Coast dinosaurs.

>Regardless of these lingering questions, the recognition of a valid Nanotyrannus means we need to rethink a lot of what we "know" about T. rex and its kin. We need to re-evaluate every species, describe more fossils, and re-do all of the studies that assumed Nano was invalid.

>Lots more remains to be done on the Dueling Dinosaurs, but for now we can say that the world of the last days of the dinosaurs just got a lot more vibrant. Dinosaurs weren't in a long-term decline before the asteroid hit; they were innovating and diversifying right up to the end.

>Before I end, I want to give a shoutout to the amazing scientist who made all of this possible. Thank you so much Lindsay, for everything. I learned so much about being a scientist while I worked in your lab - lessons I'll never forget, and I hope to teach to students of my own.

>If it weren't for Lindsay's hard work, grit, and determination, the Dueling Dinosaurs may never have made it to a museum collection. Our field owes her, and everyone who worked with her to bring these specimens into the public trust, a debt of gratitude.

>And now that you've made it to the end, you should READ OUR PAPER here: https://www.nature.com/articles/s41586-025-09801-6

(The link to the paper is broken.)

>>5066667
>>5066668
>>5066669
>>5066670
>>5066672
Holy sloppa, is the rest of the internet really just in this state of bloviation now?

There seems to be this article though: https://www.nature.com/articles/d41586-025-03553-z

>>5066650 (OP)
For me, it’s the forearm bone and tail vertebrae count that is the most convincing, hbu?

>>5066667
>>5066668
>>5066669
>>5066670
>>5066672
TL;DR
>Nanotyrannus hands are fucking huge. They had enormous claws, well defined muscle attachment sites and a vestigial third finger.
>Certain skull features don't change, and said features CAN'T change at all
>Has 5 more teeth then T-rex, and they didn't lose teeth like that
>Histology confirmed that the individual was 20 years old and done growing at the time of death.
>Also there's two species of Nano now

https://www.youtube.com/watch?v=Y5EB6zcrCOU
It isn't just real; there's two species of it now.

>>5066738
>come back from the grave not just with one species but two

>>5066650 (OP)
I remember seeing a comparison of the arms years ago. I thought it’d turn out to be an albertosaurine though

>the dueling T-Rex was a Nano
Huh. Wasn't that fossil the whole basis for how we believed T-rexes interacted with Triceratops?

>>5066796
Not the whole basis for it just a really nicely preserved example. A better question is what was that little retard doing trying to hunt an adult triceratops

>>5066650 (OP)
No, sorry.

>>5066738
I'm not going to trust the expertise of someone that can't even put the hands on the animal correctly.

>>5066823
>OH MY GOD IS THAT HAND ON BACKWARDS?? AND STILL IN THE ROCK??? IMGOINGINSANEAAAAAAAHHHHHH

>>5066721
Definitely the arm.

>>5066738
Who dressed this bitch

>>5066738
Miring the sneaks.

>>5066811
The little retard was outweighed 12:1 by the triceratops. He must have been hongry.

>>5066811
>>5067074
>The "dueling" inference comes from the numerous injuries sustained by both dinosaurs, including a tooth from the tyrannosaur embedded within the Triceratops, although it is not known whether they were actually buried fighting one another.
I'm hedging my bets a flood or something killed them instead of each other

>>5067082
Why are we getting this drawing of a fossil and not an actual photo of it

>>5066650 (OP)
Video that explains a bunch of details by one of the guys involved.
https://www.youtube.com/watch?v=Y5EB6zcrCOU

>>5066650 (OP)
Another video that explains a bunch more details.
https://www.youtube.com/watch?v=NY273id9yk4

>>5066650 (OP)
>actually all of those miniature t. rex fossils are an entirely different species and we don't have any fossils of juvenile tyrannosaurs at all actually
retarded "science" like this is beginning to make me think fundies are right about dinosaurs

>>5067104
The drawing depicts the fossils as they were intially found out of the ground. It apparently had to be taken apart in order to actually be transported and thus they aren't in this exact same pose now.
>>5067163
There's still SOME unambiguous T.rex juvies.
>LACM 23845
>MOR 6625 (aka Chomper)
>The "Teen Rex" at Denver
The problem now is finding ways to tell the two apart in future.

>>5067191
>The problem now is finding ways to tell the two apart in future.
the point of the taxonomic diagnosis is to list the ways to tell the two apart.

if we can't tell them apart, they're the same species. If they're different species, the diagnosis lists how to tell them apart.

>>5067163
"Science" was way more retarded when they were trying to score the idea that T. rex was somefuckinghow metamorphosing itself as he grew up.
Nanotyrannus looks way different than an adult T. rex, and the idea that he was a teen T. rex was always stupid anyways

T. rex fans are gullible manchildren who want to make their favorite childhood dino as unrealistically badass as possible. I'm glad they are being silenced right now.

>>5067197
Actual seething lol
And I'm happy to have another Tyrannosaur honestly. I love all of them.

>>5066736
>CAN'T
You'd think paleontologists would learn to stop telling Life what it can and can't do after being wrong the first 700 times. The cardinal rule of paleontology is that paleontologists NEVER learn from their mistakes.

>>5066827
>Is that a trackway from a living Theropod that shows pronated hands?!?!? AH HELP I'M GOING INSANE! THIS DOESN'T EXIST!!!

>>5067119
>>5067120
>SURELY, THIS one has feathers? Right??

>>5067191
>(It was real in my mind)
All taxonomists are idiots. This is what happens when you fail ecology. There generally will not be 20 species of similar megafauna in the same ecosystem. Certainly not the size of Dinosaurs. The simplest solution is that these are just juvenile T. rexes. But that doesn't get as much attention or advance careers as well, which is apparently the primary purpose of "science" these days.

>>5067197
Can you imagine a baby animal having different proportions from an adult!? This clearly means that babies are an alien species. I mean look at their stumpy limbs and giant heads. I mean, losing one set of teeth to gain an entirely different one? That's fantasy. Only an idiot would claim these are the same species. I'm not sure where all the juvenile humans are.

Imagine your entire career relying on cultivating this level of retardation on a daily basis.

>>5067191
>Brusatte

Am I going insane or did half the thread not read the fucking paper? I feel like people are spouting ancient arguments while ignoring all the new information.
I was a hardcore Nano denier until a few months ago, Bloody Mary is completely convincing, and earlier stuff about juvenile Tarbosaurus should have been cluing people into something not being right with our current: "Massive growth spurt where in a super brief time it completely changes size and shape" model of Tyrannosaurus.

Is it weird that there's a completely separate genus that looks kinda similar to how the apex predator looks as a juvenile? I guess a bit, but then look at all the different types of cats in Africa, you could probably make similar arguments.

>>5067301
Nobody reads papers anymore because they're full of lies. We already know what they have to say because it's always the same bullshit.

"We're certain this obvious juvenile dinosaur is an adult because bones, blah blah, sutures blah blah."

They've only written some version of this shit at least dozens of times. Modern paleontology is the unqualified glorified calculator STEMtard crying "adult" non-stop.

>>5067305
>we claim the earth is round because measurements, bla bla rockets (that only the freemasons can fly), bla bla astronomical observations and "MATH". science is bullshit! it says right here in the bible that the earth has four corners! Calculator stemtards aren’t people
That’s what you sound like

>>5067278
Daspletosaurus and Gorgosaurus coexisted together.

>>5067278
For being a nigga you have clearly never been to africa

Oh they mad. They so mad when you stop Trusting the Experts™.

>>5067342
You've become so damn cynical lately.

>>5067357
Gee, I wonder if scientists should be skeptical in general or even specifically skeptical in science and academia given the past decade and a half of shenanigans in STEM?

>>5067358
Global warming is a fact and the earth is round. Seethe more couchfucker.

>>5067359
How dis make u feel?

>>5067361
Like we’re about to see normies finally realize which country posts all the BBC and anti-white shit (its india btw, israel actually is our greatest ally)

>>5067280
Here, I'll give you a reply to make you feel better about being retarded.

No! Tyrannosaurus occupied every predatory niche! There's no room for other species!

>>5067191
Jane was formerly an "unambiguous" T. rex juvenile
now they're saying she's a TOTALLY different genus

>>5067197
>the idea that T. rex was somefuckinghow metamorphosing itself as he grew up.
look at a newly born foal and an adult horse
same difference

>>5067363
Who do you think is paying indians? And guess where they're getting the money.

>>5067371
tell me when a baby horse is born with legs longer than an adult and shrinks them to adult size, then you'll have a point

>>5067426
I assure you, Nanotyrannus, nor any other Dinosuar has features that are larger as juveniles than adults, though STEMniggers have tried to claim it many, MANY times. They're lying. Reptile size variation is much more extreme than in mammals. Camarasaurs have two random size classes for no readily apparent reason, which may (or may not) relate to gender.

>>5067426
>Nanotyrannus' legs are bigger than Tyrannosaurus!
>...that's why it's half the height

>>5067555
He’s talking about the forelimbs. Nanotyrannus has longer arms and claws than an adult T. rex 10x its weight

>>5067555
Are you usually this confidently incorrect?

>>5067373
Usually it seems to be Russia and the answer is selling energy to Europe, but there's been some complications on the selling energy to europe thing for the last 2 years, so now they're paying the Indians straight in petroleum which they can sell to wash the sanctioned nature of the product. Now, Russia is the number one nation in terms of Israeli dual citizenship, so there's overlap in motive and method.

>>5067440
> Camarasaurs have two random size classes for no readily apparent reason, which may (or may not) relate to gender.
Are you referring to the species? Because its been long known that the sizes of the animals in the Morrison biota get larger as the the age gets younger.(Morrison covers about 9 and a half million years of deposition) Older tends to be smaller, bigger tends to be larger.

>>5067650
>bigger tends to be larger.
Younger, just woke up so im still a bit retarded

>>5067577
>>5067570
>say legs
>"ACTUALLY I MEANT THE ARMS"
that's a cope

>>5067696
A horse is all legs, ding-dong. That anon was just making a comparison.

Pic: Larry witmer comes in with a characteristically sane and reasoned take.

>>5067710
Pt 2

>>5067278
>>5067332
Plus Alioramus and Tarbosaurus - the latter also being potentially over-lumped. “Maleeovosaurus” has some post-cranial differences that are suggestive.

>>5067696
Do you call the forelimbs of a horse legs, arms, or wings, you disingenuous twat?

>>5067712
And if it turns out Asiatyrannus is a juvenile and that large mysterious tooth belongs to an adult then Asiatyrannus and Qianzhousaurus could be added to the list of big and small Tyrannosaurids that lived together.

>>5067802
Indeed. This should not be especially revelatory, tho. Diversity is the rule, not the exception. We just need to keep digging more and not assume we know so much.

Don’t tell that to the die-hard cladists and their beloved matrices, tho. God forbid they touch a fossil for themselves.

Speaking of diversity, it’s high time albertosaurinae got some new members. Teratophoneus (pic related) always struck me as albertosaur-like. It’s good that folks stepping away from forcing everything into tyrannosaurinae

>>5067802
Pic of tooth available?

>>5067804
The paper recovers an expanded Albertosaurinae in both of its phylogenies, both Bistahieversor and more interestingly Jinbeisaurus as Albertosaurines

>>5067696
You’re not very intelligent are you

>>5067813
oh and i forgot to mention! It also picks up an unnamed genus/species that is sister to Gorgosaurus.

>>5067721
>Do you call the forelimbs of a horse legs, arms, or wings, you disingenuous twat?
In veterinary anatomy the leg is the lower part of the hind limb. Commonly known as the shin, it doesn't include the thigh, foot, or any part of the forelimbs (arms).

this is confusing to the uneducated such as yourself who are used to referring to the whole hindlimb as the leg, and often to the forelimbs as legs also.
But veterinary anatomy is based entirely on human anatomy, so the correct usage of the term "leg" is for the shin of the hind limbs only. The forelimbs are called arms or forelimbs. The upper part of the hind limb is called the thigh. The whole appendage is called the hind limb. None of the limbs are correctly called "legs." That's uneducated speak.

>>5067721
"wing" is also a confusing term not often used in vertebrate anatomy because some animals have wings on the forelimb, some have wings on the hind limb, and some have wings that attach to both fore and hind limbs. So when comparing different animas, "wing" is useless as an anatomic designation. When talking about bird wings we're going to call them forelimbs or arms. Other animals might have wings elsewhere. Pectoral fins perhaps. Or expanded ribs. Whatever.

>>5067721
similarly we make distinctions between the front and back "feet" on vertebrates

the back feet are called pes (feet). The front "feet" are not feet, they're manus (hands). This is again because veterinary anatomy is based on human anatomy, and humans have hands on their front limbs (arms).

the front "feet" of a dog are called hands (manus). The front hooves of a horse are also called hands. The front "feet" of any vertebrate are called hands, and the front limbs are called arms.

>>5067813
Yes, that’s what I was alluding to :)

>>5067815
Yeah I’ve been patiently waiting for the new gorgosaur to get described. It’s name will piss off Horner and Carr hehe

>>5067853
Yes everyone knows this, you’re just being pedantic.

Dinosaur bones are so cool. All paleoart should be skeletons.

>>5067805
https://www.researchgate.net/publication/270875350_Large_theropod_teeth_from_the_Upper_Cretaceous_of_Jiangxi_southern_China

>>5066668
> which we think *cannot* change during growth in any reptile
Retard here with a question.
I thought that theropods were specifically very not reptiles. So why would that inability to change show that nanotyrannus isn’t a juvenile t-rex?

>>5067861
>Yes everyone knows this,
then why do we have five posts itt from people who clearly don't know this?
rhetorical question, don't answer.

>>5067940
Birds are theropods and theropods are dinosaurs and dinosaurs are archosaurs and archosaurs are reptiles (whatever “reptile” actually means)

>>5067940
If the sinus is present in Nanotyrannus but not in adult Tyrannosaurus AND the sinus can't be lost during growth, that would prove it to be a different species.

this ignored the dozens of theropod dinosaurs such as Allosaurus where some individuals have a jugal sinus and others don't and we don't consider the presence or lack of the jugal sinus to be indication of a different species. Also in many cases the sinus is present in different forms and sizes in the same species. Also true of several sinuses and fenestrae. E.g. the maxillary sinus or fenestra in Allosaurus is sometimes present, sometimes absent, sometimes halfway present. None of these conditions is taken as evidence of a different species.

basically in that regard we have special pleading in the case of Tyrannosaurus, where a feature that does NOT indicate different species in other animals is being used to erect a new species in Tyrannosaurus. Happens a lot. T. rex gets way more attention than other dinosaurs, and a lot of it isn't great.

>>5067951
or to put it very simply,

if every variation in cranial sinuses indicates a new species, we've instantly got close to a million new dinosaur species, because no two skulls have exactly the same sinuses.

>>5067951
>>5067954
Even if cranial sinuses are shit for determining new species of dinosaurs, the tooth counts and arm length and finger counts are excellent indications of a new species.

Subadult and adult theropods have roughly the same tooth counts, with some individual variation. No dinosaur that we know of loses fingers as it gets older. And no dinosaur that we know of has arms that shrink over time.

>>5066674
>bloviation
thanks for teaching me a new word today anon

>>5067274
nobody said they couldn't pronate hands retard, they're just not left pronated when idle.

>>5067951
>Allosaurus

Horrible example.

>>5067961
>nobody said they couldn't pronate hands retard
Carpenter specifically said they couldn't pronate their hands, with the exception of long armed theropods like raptors.
>>5067962
>Horrible example.
not the only example. Basically every theropod for which we have more than one skull that is derived enough to have cranial pneumaticity shows variation in the location, presence, extent, and form of sinuses.

>>5067274
that track could be left without pronating the hand

>>5067280
>>5067371

Jane's arms are bigger than Sue's lol. Not proportionally, just outright bigger

>>5067948
You lost the argument

>>5067322
You're having severe delusional. For your own good, seek help.

>>5067322
You're experiencing severe delusions. For your own good, seek help.

Lel, we’ve got a Trannysaurus regina fan here seething that xer favorite trans rights icon didn’t occupy every predatory niche bigger than 1 kg in its environment?

>>5067948
It’s not that nobody knew this, it’s just that everyone knew what was meant without needing to be autistic about it

>>5067274
I’m not the one saying they can’t pronate their hands. You’re the one saying they couldn’t bend their hands as >>5066827 is

>>5068026
If the thread is arguing about whether or not forelimbs are legs
And nobody is pointing out that neither forelimbs nor hind limbs are legs,

I taught you all something you either didn't know or lack the balls to say

>>5068012
what do you mean? they are all just big lizards

>>5068034
>legs aren't real
?????????????

Pretty cool. I was wrong about this one. And frankly it makes more sense in the end, doesn't it. Niche partitioning has always been a staple of every single ecosystem.

>>5068034
No one misunderstood until you came in with your mega-autism and muddied the waters. You make things worse and the discussion less interesting.