A New Type of T Rex

A remarkably complete tyrannosaur specimen was unearthed in the middle of Montana. It may finally settle one of the most contentious arguments in paleontology. While it’s at it, it might also upend our understanding of Tyrannosaurus rex, one of the most famous extinct animals on Earth.

The new fossil, along with others that had been assumed to be teenaged T. rex, are actually part of a distinct group called Nanotyrannus. Researchers had discovered differences in the bones, as well as evidence that the new fossil was a mature adult that had stopped growing, not an immature T. rex. The study also creates a more diverse picture of predators of the late Cretaceous by making the case that there were two species of nanotyrannus.

Originally, nanotyrannus were first identified as a separate species in the mid-1940s, but many came to believe they had been misclassified. They said the smaller versions were simply T. rex teenagers.

But if these were not teenagers, other questions arose: Did these different species interact? Did they hunt different prey? What did T. rex adolescence look like?

This paper states that Nanotyrannus is a distinct tyrannosaur species. Which indicates a reassessment of tyrannosaur classification is needed. Which is how science works.

For decades, nanotyrannus proponents had been marginalized by scientific consensus that they were young tyrannosaurs.

In a paper published in 1946, Smithsonian paleontologist Charles Gilmore described a new carnivorous dinosaur whose skull was found in Montana. At the time, he described it as a Gorgosaurus, a slightly smaller species of tyrannosaur. Four decades later, the skull was reanalyzed and a new paper proclaimed it a nanotyrannus.

Nanotyrannus lancensis was less than half the length of T. rex, although it was a relatively long-limbed animal. It is thought it would have been more graceful, not like the stocky, stomping brute of a T. rex.

Thomas Carr suggested in 1999 that nanotyrannus were simply youthful T. rex, and that explanation took hold.

In 2021, a North Carolina Museum acquired a 30,000 pound slug of bone and rock. They thought it contained a juvenile T. rex and a triceratops that had been buried together in Montana. Soon, they realized it was not a juvenile because its hand was really big. Far bigger than the hand of a fully grown T. rex.

A detailed analysis of the fossil found distinctive differences, such as the way cranial nerves threaded through the skull and the patterns of sinuses in the skull. Then, they cut into a limb bones, where the growth rings showed it to be about 20 years old, and it was a mature individual that had stopped growing… at less than half the length of a full-grown T. rex.

So they reexamined 120 existing fossils. One (called Jane) was assumed to be a young T. rex. She was a nanotyrannosaur, but a different species than the others they were studying.

So, kids can still have a favorite dinosaur, even a favorite tyrannosaur. It just might not be the well-known tyrannosaurus rex.

 

https://www.msn.com/en-us/news/world/one-of-science-s-biggest-dinosaur-debates-may-finally-be-settled/ar-AA1PvttY?ocid=hpmsn&cvid=6904de58713a4fa5aca269a56dd9bb74&ei=71

Dinosaurs

Like most kids, I had a steady interest in dinosaurs when I was young. I never truly outgrew that interest, and the science magazines I read don’t have much to report on them very often. How disappointing. I long to learn all the new stuff they’ve learned since I was a kid. Can you imagine my surprise a few decades ago when I discovered Fred Flintstone’s powerhouse Brontosaurus never actually existed? It was the result of a few bones that did not necessarily belong together and a scientist’s active imagination while trying to put them together.

One of my school science projects was on dinosaurs. I bought several giant bars of Ivory soap and tried to carve them into various dinosaurs. The T-Rex didn’t want to stand up, the stegasaurus’ back plates were difficult to carve without breaking them off. The easiest to carve was the brontosaurus, which way back then still had a place on the dinosaur family tree.

I can’t do justice to dinosaurs in a few hundred words. After all, they were around - in one form or another - for millions of years. So I plan to look around, pick some interesting versions and report on them over the course of several months.

What do you think you know about dinosaurs? Were they all cold-blooded? Covered in reptile scales or simply skin similar to our own? Did they do any parenting of their young, or simply lay their eggs and move on through the countryside? Did they really evolve into birds? How big did they get? What was their smallest representative? Are there any ‘dinosaurs’ alive today, or maybe animals that look very similar to their ancient ancestors?

I remember a story - I don’t remember if I saw it visually or read it - where a group of hadrosaurs (That’s what I remember their type being, but I may be completely wrong.) had left Earth in some fashion back in the Long Ago, and established a home on another planet in another system. And now their descendants were space travelers and meeting humans in the vastness of space.

Wouldn’t that be something?

Well, since we’re approaching that point where we may be space traveling in a few generations (meaning, outside our home system), maybe we should be considering what evolved dinosaurs might be like. And to do that, we should start by learning what dinosaurs were actually like.

Any suggestions you want me to look at?

Tyra

 I thought I’d take a look at Tyrannosaurus Rex. We all remember Tyra, right? Always represented as having a mighty roar and sharp, pointy teeth, and teeny, tiny forearms that wouldn’t even reach its mouth. Why would it evolve with such useless arms?

The first thing I discovered was that those tiny arms were quite strong, and each ‘hand’ had 2 sharp claws. So in a fight, if its mouth was already full of opponent, or it was still looking for the chance to sink its teeth into an opponent, those claws could be used to protect its belly, maybe? Well, not its abdomen, but the chest area. Any attack below that would call for leg action, either to stab or slice with its bigger foot claws, or to back up and get those fearsome teeth involved.

Other uses for these arms have been suggested; that they were used to grasp the female during sex, or that they assisted Tyra in rising from resting on the ground. Or from falling down, or being knocked down, or whatever. But one suggestion is actually supported by biomechanical analysis, and that is that the arms held Tyra’s struggling prey as the teeth did the work of killing it. Those arms are almost always shown bent at the elbow and held close to the body. And there’s a reason for that; Tyra’s shoulders could only move 40°, and its elbow only moved a maximum of 45°. So, no charades or sign language for this creature! To help you think about that, a healthy human shoulder can move 360°, while the elbow allows 165° of movement.

I had trouble picturing these restrictions. If you want, try this: Hold your arm down along your body and bend your elbow to make the forearm perpendicular to your body. This is your starting position. Now, keeping the elbow stiff in that position, raise your upper arm to not quite half-way to being perpendicular to your body. That is about how much Tyra’s shoulder could move. Now, extend your forearm to halfway between where it is and it being straight at the elbow. Imagine all the things you and I would not be able to do if that was all the further we could move those joints!

Okay, so these tiny arms may have been somewhat useful, but why did they evolve that way? What were Tyra’s ancestors like? And are there any descendants still around?

It was hard to find anything definitive about ancestors. The family tree that includes Tyra has many branches in that same time period, and they all seemed to have ‘stunted’ arms. A recent discovery from an earlier epoch held an almost complete skeleton of a very similar creature, possibly an ancestor of Tyra and/or other branches of that family tree. That article did not include much description - only that it was ‘horse-sized’ compared to Tyra’s ‘elephant-size - but the ‘artist’s rendering’ showed that ancestor as a skinnier Tyra, with somewhat longer and looser arms. That article stated that the ancestor already had a big brain, keen eye-sight, and sharp hearing at lower frequencies, and deduced that the Tyra family had developed these ‘smarts’ before it developed the brawn.

And of course, when the meteor hit and killed almost all the herbivores, a few Tyras - out of sheer desperation - shed over 99% of their weight, sprouted feathers and became birds. No, not really. When the herbivores died, Tyra’s family tree died, too. But some distant relatives - the maniraptoriformes family - did live on, and some of those did develop into modern birds. Which is good, because those tiny, practically frozen arms of the Tyra family were not going to launch a Tyra into the air, no matter how many feathers it had!

And now I’ll be shoving all this information into the grist mill that is my day-dreaming mind. Perhaps, on another planet, the end of the dinosaurs did not happen quite so fast, and the Tyras did manage to slim down and learn to fly. What do you think? Some kind of bird? Or dragon? Or something else entirely?

https://en.wikipedia.org/wiki/Tyrannosaurus

http://www.abc.net.au/news/science/2016-03-16/pregnant-t-rex-discovery-sheds-light-on-evolution-of-egg-laying/7251466

http://www.abc.net.au/news/2016-03-15/t-rex-tiny-ancestor-could-hold-clue-to-predator-dominance/7246928

Can Dinosaurs Be New?

One of my Junior High science projects was a ‘diorama’ and report on dinosaurs. I carefully carved my 3 chosen specimen from Ivory soap bars and painted the inside of a cardboard box to be their home.

That was so long ago, the dinosaurs I carved out and reported on were the stegosaurus, tyrannosaurus rex, and the... brontosaurus. Nobody talks about brontos anymore. It’s kind of like they never existed. Actually, they never did. Somehow, somebody stuck the wrong head on another dino’s body, and nobody caught it until-- Well, I don’t know when they figured it out, sometime between my science project and the time my kids went into their ‘dinosaur’ stage.

Since then, there have been tons of dinosaurs and other creatures discovered. Instead of a world inhabited by a handful of giant, scaly lizards, we can now picture a world inhabited by any number of lizards, fish, insects, some mammals, and birds. Even some reptiles that disguised themselves as birds.

Take, for instance, the one I read about this week; the Changyuraptor yangi. It was covered in feathers, including foot-long tail feathers. It was a reptile, and it couldn’t fly. It might have been able to glide, or as one scientist put it, “... if you pushed them out of a tree, they'd fall pretty slowly.”

This despite being described as having 4 wings. Really? No, not exactly. The feathered forelimbs were somewhat akin to a bird’s wings. The backlimbs were also feathered, in such a way that they looked like wings. Lots of feathers, but not a bird.

The Changyuraptor was discovered in China, which seems to be THE place for any self-respecting feathered reptile to have lived. Stegosaurs lived in Western America some 25-30 million years earlier. Since they had armour instead of feathers, I guess they couldn’t aspire to live in China. T.Rex  and their relatives seemed to live where-ever they wanted.

I’m glad I didn’t have to try to carve 4 ‘wings’ and feathers on a creature for my science project. Still, my hackles rise a little when I see a headline about a ‘NEW’ dinosaur being discovered. Whatever their form, dinosaurs aren’t ‘new’. Their dead body has been sitting in the ground for millions of years. It’s not their fault if we’ve only just found them.