Redesigning a tyrant: Meet the new Tyrannosaurus rex

[Yutyrannus]

We do have direct evidence, just not as direct as some people think is necessary. Just to recap:

-We know that relatively close relatives of Tyrannosaurus had feathers, and we know that Tyrannosaurus had the genetic capacity to grow feathers.
-We know that animals as large as Tyrannosaurus still retained their feathers.
-We know that it's incredibly speculative to assume that any animal would loose integument as it grows older (all ages or nothing).
-We have impressions of two different forms of dermal surface for Tyrannosaurids, why would they have scales and bare skin?

Given this it can be said with relative certainty that unless early tyrannosaurids were aquatic (however interesting that would be I can't see it) and then returned to land there's no reason for them to loose their feathers. But even then it's unlikely given that feathers are much better at serving an animal underwater than hair is.

And then we do have fossil (what some people claim is the only thing that qualifies as "direct") evidence too, people arguing against feathers will often cite the presence of both scale and skin impressions in tyrannosaurid fossils but really that makes quite the contrary picture. The scale impressions are all from exactly where you would expect to find scales on an otherwise feathered animal, the thigh, the bottom of the foot, the underside of the tail, and the very underbelly. Why people argue the scale impressions on the bottom of the foot are evidence against feathers I can't fathom, but I've seen it done. These scale impressions decidedly point to neither conclusion, as these areas would likely be scaled regardless of the rest of the animal, the skin impressions however, are far more telling. Skin impressions from the flanks and throat of tyrannosaurids are a huge hole in the argument of scaled tyrannosaurids, since there is no reason why they would have bare skin and scales.

To sum up, it is possible Tyrannosaurids could have lost their feathers, but it's certainly not the conservative assumption.

Exactly. Tyrannosaurus having feathers is, at least for now, the most conservative assumption that can be made. It is possible that it lacked feathers and/or was mostly scaly, but that is far more speculative considering there is no evidence for that at all in any tyrannosauroid.

It's also worth noting that their are more skin impressions from Tarbosaurus, and those do show a dewlap of bare skin on its throat, but this is also no evidence of it lacking feathers as plenty of birds have similar structures. Sadly this fossil was destroyed by poachers, however .

[Plasticbeast95]

What about scale impressions found with some tyrannosaurus remains?

P.S. you wouldn't happen to be on Carnivora, would you?

[Yutyrannus]

What about scale impressions found with some tyrannosaurus remains?

P.S. you wouldn't happen to be on Carnivora, would you?

None of them are much bigger than a playing card and all of them are known from the places that one would expect to have scales (the feet, underside of the tail, etc.).

I used to be.

[Plasticbeast95]

Still, its proof that T. rex did have scales. And that's all I was asking.

[Yutyrannus]

Still, its proof that T. rex did have scales. And that's all I was asking.

If someone were to find an ostrich fossil with scale impressions from the foot that would be proof ostriches have scales. They doesn't prove anything about Tyrannosaurus lacking feathers, if anything the fact that scale impressions of tyrannosaurids have never been found in areas other than the underside of the tail, the underbelly, and the legs would be evidence that there were not scales over the rest of the body. And, as stargatedalek mentioned, if it were scaly, there wouldn't be skin impressions showing bare skin and scale impressions. No reptile has both scales and bare skin, birds have both but also have feathers, there is no living example of an animal with both scales and bare skin but no other kind of integument.

Also, I never said Tyrannosaurus lacked scales entirely. Now that would be speculative .

[Plasticbeast95]

No, I was just asking about the scale impressions, I'm not saying that T. rex was bald.

[Yutyrannus]

No, I was just asking about the scale impressions, I'm not saying that T. rex was bald.

You said that "at the most" they had feathers as chicks and lost  them as the grew.

[Plasticbeast95]

No, I was just asking about the scale impressions, I'm not saying that T. rex was bald.

You said that "at the most" they had feathers as chicks and lost  them as the grew.

But that did not have to do with my question, which was simply about the known scale impressions. I was just asking if they were still valid or not.

[Yutyrannus]

No, I was just asking about the scale impressions, I'm not saying that T. rex was bald.

You said that "at the most" they had feathers as chicks and lost  them as the grew.

But that did not have to do with my question, which was simply about the known scale impressions. I was just asking if they were still valid or not.

Oh, okay, then. Sorry for the misunderstanding .

And yes, they are definitely valid, just not evidence against feathers.

[Rain]

-We know that animals as large as Tyrannosaurus still retained their feathers.

There's a considerable size difference between a Yuty and Tyrannosaurus. Is there something bigger than a Yuty that had feathers ?

[Plasticbeast95]

No, I was just asking about the scale impressions, I'm not saying that T. rex was bald.

You said that "at the most" they had feathers as chicks and lost  them as the grew.

But that did not have to do with my question, which was simply about the known scale impressions. I was just asking if they were still valid or not.

Oh, okay, then. Sorry for the misunderstanding .

And yes, they are definitely valid, just not evidence against feathers.

Its ok, I forgive you.

I never said they were,

[Loxodon]

-We know that animals as large as Tyrannosaurus still retained their feathers.

There's a considerable size difference between a Yuty and Tyrannosaurus. Is there something bigger than a Yuty that had feathers ?

The size difference is of 2 meters, hardly considerable. Not to mention, 12 meters is not even the average size for a tyrannosaurus, Sue was an abnormally large individual, most tyrannosaurs "only" reached around 10 meters, which is the same size as the largest yutyrannus.

[Arioch]

-We know that animals as large as Tyrannosaurus still retained their feathers.

There's a considerable size difference between a Yuty and Tyrannosaurus. Is there something bigger than a Yuty that had feathers ?

Yep, Deinocheirus. It was roughly the same size as Rexy.

[Rain]

-We know that animals as large as Tyrannosaurus still retained their feathers.

There's a considerable size difference between a Yuty and Tyrannosaurus. Is there something bigger than a Yuty that had feathers ?

The size difference is of 2 meters, hardly considerable. .

I'm sorry, but did you just say 2 meters is hardly considerable?  . You know, 6 feet 6 inches? The size of a basketball player isn't considerable? Well then.. Also, comparing an oversized Yuty to an undersized Rex makes no logical sense.

-We know that animals as large as Tyrannosaurus still retained their feathers.

There's a considerable size difference between a Yuty and Tyrannosaurus. Is there something bigger than a Yuty that had feathers ?

Yep, Deinocheirus. It was roughly the same size as Rexy.

Hmmm, very interesting. I've surprisingly never heard of it. Thanks, you've given me something to look into !

[Gwangi]

There is no direct fossil evidence for feathers on Deinocheirus even if it's highly likely that they had them.

[tyrantqueen]

The size difference is of 2 meters, hardly considerable. Not to mention, 12 meters is not even the average size for a tyrannosaurus, Sue was an abnormally large individual, most tyrannosaurs "only" reached around 10 meters, which is the same size as the largest yutyrannus.

What is it about Sue that makes you think it is abnormal? The Wankel Tyrannosaurus was eleven metres and is thought to only have been around eighteen years old, and would have been still growing. I think they were capable of reaching Sue's size but due to preservation bias we don't have many fossils.

[Gwangi]

The size difference is of 2 meters, hardly considerable. Not to mention, 12 meters is not even the average size for a tyrannosaurus, Sue was an abnormally large individual, most tyrannosaurs "only" reached around 10 meters, which is the same size as the largest yutyrannus.

What is it about Sue that makes you think it is abnormal? The Wankel Tyrannosaurus was eleven metres and is thought to only have been around eighteen years old, and would have been still growing. I think they were capable of reaching Sue's size but due to preservation bias we don't have many fossils.

I'm having a difficult time figuring out why there would be a preservation bias towards younger, smaller T. rex instead of older, larger T. rex fossils. Is there something I'm missing here?

[tyrantqueen]

The size difference is of 2 meters, hardly considerable. Not to mention, 12 meters is not even the average size for a tyrannosaurus, Sue was an abnormally large individual, most tyrannosaurs "only" reached around 10 meters, which is the same size as the largest yutyrannus.

What is it about Sue that makes you think it is abnormal? The Wankel Tyrannosaurus was eleven metres and is thought to only have been around eighteen years old, and would have been still growing. I think they were capable of reaching Sue's size but due to preservation bias we don't have many fossils.

I'm having a difficult time figuring out why there would be a preservation bias towards younger, smaller T. rex instead of older, larger T. rex fossils. Is there something I'm missing here?

Yes, preservation bias is the wrong word. I made a mistake. I want to say that the fossil record is too incomplete to say for sure that twelve metres is abnormal for a Tyrannosaurus. Maybe the others could have reached that size but never got a chance.

[Dinoguy2]

Actually it is preservation bias. It's simple statistics, and this has been published on a few times. If you think of a growth series as a bell curve, any given fossil is much more likely to come from the middle of the curve (mid sized sub adult) than the extreme ends of the curve (juvenile or fully mature adult). And when we look at histology, this is exactly what we see. Almost all dinosaur fossils are subadult. Only when we get very large sample sizes, like in Tyrannosaurus and Triceratops, do we start to find the remains of old adults and young juveniles.

In the wild, most animals do not have the chance to reach full size, statistically speaking, so average size will always be lower than maximum size.

Our sample size of Yutyrannus is 3, while our sample size of T. rex is more like 50 for decent specimens. If you crunch the length estimates on Theropod Database, the average size for both are about equal. Given the smaller sample size, it's not unreasonable to say that on average, Yutyrannus and Tyrannosaurus were about the same size.

Either way, using this data to conclude that tyrannosaurus was significantly larger to explain feather differences is mathematically absurd, unless you want to propose that tyrannosaurus had Yutyrannus feathering up until the last couple years of its life when they suddenly disappeared when it crossed those extra 2m in length!

[tyrantqueen]

Either way, using this data to conclude that tyrannosaurus was significantly larger to explain feather differences is mathematically absurd, unless you want to propose that tyrannosaurus had Yutyrannus feathering up until the last couple years of its life when they suddenly disappeared when it crossed those extra 2m in length!

Don't worry, I don't