Redesigning a tyrant: Meet the new Tyrannosaurus rex

[Rain]

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!

Not once did I say that. Scroll up and check before posting, will you?. I was arguing the fact that Loxodon believes 2 meters is hardly considerable. Because of Darwin's theory I question what the purpose of a big dino like T rex having feathers would be  but I don't necessarily claim its wrong. In fact, if you go back a page, you'll see that I told Arul it wouldn't be far fetched to say it had feathers. What I spoke out against was Patrx's rude tone towards plasticbeast and Loxodon claiming 2 metres is hardly considerable .

[Gwangi]

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!

Yes, I understand all this but thanks for sharing it anyway. That's what I was trying to hint at myself, that since Sue with her large size is in the minority of specimens that she cannot represent an average size based on what we have for the species. There is no reason why smaller T. rex specimens would be favored in preservation over larger specimens unless they died before they could reach a larger size. That doesn't sound like a preservation bias to me in which conditions favor the fossilization of one animal over another.

[stargatedalek]

I think Gwangi is right here, in order to be a preservation bias there would need to be a characteristic of younger animals that made them fossilize better. Young adults are found more commonly in the fossil record because they are more common in the ecosystem, I wouldn't call that preservation bias. Aside from that rather trivial point however I think most of us are in agreement regarding the size averages in regards to the animals age.

[Loxodon]

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 over-sized Yuty to an undersized Rex makes no logical sense.

In the context of >10 meter animals, 2 meters is not a very big difference, no. There is absolutely no reason to assume that anything that goes for a 10 meter long animal would not also go for a 12 meter long one. Besides, as the others have helped clarify, Sue is probably not an ordinary individual anyway. Even assuming preservation bias, considering how many Tyrannosaurus specimens we have, we can safely conclude that she was either merely an abnormally large individual, or a member of a specific population of large animals that existed at one point in time. Whatever the case, most tyrannosaurs were smaller than her.

This is all for naught however, as you have yet to provide an explanation as to why a 2 meter difference would have any effect on the animal's integument anyway. As it stands, with all the data we currently have, feathers on Tyrannosaurus rex is the default assumption. Saying that T. rex had feathers is not speculation, it is being conservative.

[allosaurusrock]

I, personally love feathered dinosaurs. I'm one of those people pushing for every dinosaur to have feathers, and, my own theory, every dinosaur had a beak. So, feathered T-rex for the win! But if I was the one doing the reconstruction, the only place scaly would be legs.

[Plasticbeast95]

I, personally love feathered dinosaurs. I'm one of those people pushing for every dinosaur to have feathers, and, my own theory, every dinosaur had a beak. So, feathered T-rex for the win! But if I was the one doing the reconstruction, the only place scaly would be legs.

This is the opposite of my views, I tend to be more conservative, giving feathers only to Theropod branches known to posses feathered members (E.G Maniraptorans). So no fuzzy Stegosaurs or feathery Sauropods for me.

[Rain]

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 over-sized Yuty to an undersized Rex makes no logical sense.

In the context of >10 meter animals, 2 meters is not a very big difference, no. There is absolutely no reason to assume that anything that goes for a 10 meter long animal would not also go for a 12 meter long one. Besides, as the others have helped clarify, Sue is probably not an ordinary individual anyway. Even assuming preservation bias, considering how many Tyrannosaurus specimens we have, we can safely conclude that she was either merely an abnormally large individual, or a member of a specific population of large animals that existed at one point in time. Whatever the case, most tyrannosaurs were smaller than her.

This is all for naught however, as you have yet to provide an explanation as to why a 2 meter difference would have any effect on the animal's integument anyway. As it stands, with all the data we currently have, feathers on Tyrannosaurus rex is the default assumption. Saying that T. rex had feathers is not speculation, it is being conservative.

If you go back and actually look instead of assuming, you'd see I wasn't suggesting it did. I was merely asking Stargate if there's any other bigger dinos with feathers (since theres a size difference between the two) as I'm unaware of them. You budded in yourself and assumed. However, I do believe it'd be unlikely for bigger Dinosaurs to have feathers without reason. Which begs me to wonder what purpose a T rex would have with feathers
Even with that context, 2 meters is 1/5th of the animal...A very considerable amount

[Dinoguy2]

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

Missed this before, but Deinocheirus has a pygostyle, which is pretty strongly associated with the presence of feathers. And as mentioned before, Deinocheirus is as large or larger than T. rex in terms of body mass, and lived in a similar, if not warmer, environment.

And yes, I meant preservation bias more indirectly, as in younger individuals are morel likely to die and then be preserved. There's probably a better term for this but I can't think of it...

And actually, all this discussion over 10m vs 12 m size differences are kind of irrelevant, because what matters here is mass, not length. While they were about the same length, on average, T. rex was much more robust and had a greater mass (~1.4t vs. at least 4.5t). So while it was only 1.2 times longer than Yutyrannus, T. rex was at least 3 times larger.

[Balaur]

Well, while the likelihood of Deinocheirus having feathers is very high, the "pygostyle" of Deinocheirus doesn't necessarily mean it had a tail fan. Some sauropods have fused tail vertebrae, similar to that of Deinocheirus, and I doubt they have tail fans.

[tyrantqueen]

And yes, I meant preservation bias more indirectly, as in younger individuals are morel likely to die and then be preserved. There's probably a better term for this but I can't think of it...

Skewed data maybe?

[Dinoguy2]

Well, while the likelihood of Deinocheirus having feathers is very high, the "pygostyle" of Deinocheirus doesn't necessarily mean it had a tail fan. Some sauropods have fused tail vertebrae, similar to that of Deinocheirus, and I doubt they have tail fans.

True, though the phylogenetic bracket of Deinocheirus makes it much more likely, as with oviraptorosaurs that have pygostyles interpreted as bearing feathers, like Anzu. Ornithomimus itself is now known to have had stage 3a ostrich-like feathers which are longer on the tail.

And yes, I meant preservation bias more indirectly, as in younger individuals are morel likely to die and then be preserved. There's probably a better term for this but I can't think of it...

Skewed data maybe?

Maybe. This is a paper that discusses the phenomenon but I don't have access to read it. http://www.ncbi.nlm.nih.gov/pubmed/16840697/ It shows, basically, that tyrannosaurids tended to die either around mid-life, or at maximum age, which makes sense given that we know dinosaurs reached sexual maturity long before full size, so evolution was not necessarily weeding out dinosaurs that died before full adulthood.

[Halichoeres]

I have the pdf if you want it.

[Plasticbeast95]

I just assume that all Maniraptorans had fuzz of some kind.

[Dinoguy2]

I just assume that all Maniraptorans had fuzz of some kind.

Given what was presented at SVP yesterday, it's more than maniraptorans and more than fuzz! If Ornithomimids are already at stage 3, then stage 2 must be more primitive and stage one even further down the tree. Look at an ostrich feathers, and that's what the most primitive Maniraptoriformes had (and Sinosauropteryx feathers are actually pretty similar, just much tinier). So the origin of basally-branched filaments must be around Coelurosauria and the origin of simple fuzz must be down around Avetheropoda somewhere unless the stages evolved REALLY quickly once feathers appeared.

[Plasticbeast95]

I just assume that all Maniraptorans had fuzz of some kind.

Given what was presented at SVP yesterday, it's more than maniraptorans and more than fuzz! If Ornithomimids are already at stage 3, then stage 2 must be more primitive and stage one even further down the tree. Look at an ostrich feathers, and that's what the most primitive Maniraptoriformes had (and Sinosauropteryx feathers are actually pretty similar, just much tinier). So the origin of basally-branched filaments must be around Coelurosauria and the origin of simple fuzz must be down around Avetheropoda somewhere unless the stages evolved REALLY quickly once feathers appeared.

You've got it all wrong, I wasn't excluding non-manies, just that all manies had fuzz (and feathers) ok? Dose this make sense?

[Dinoguy2]

I just assume that all Maniraptorans had fuzz of some kind.

Given what was presented at SVP yesterday, it's more than maniraptorans and more than fuzz! If Ornithomimids are already at stage 3, then stage 2 must be more primitive and stage one even further down the tree. Look at an ostrich feathers, and that's what the most primitive Maniraptoriformes had (and Sinosauropteryx feathers are actually pretty similar, just much tinier). So the origin of basally-branched filaments must be around Coelurosauria and the origin of simple fuzz must be down around Avetheropoda somewhere unless the stages evolved REALLY quickly once feathers appeared.

You've got it all wrong, I wasn't excluding non-manies, just that all manies had fuzz (and feathers) ok? Dose this make sense?

Ah ok, I thought you were saying you restricted that to maniraptors but not to non-maniraptors like tyrannosaurs.

[Plasticbeast95]

I just assume that all Maniraptorans had fuzz of some kind.

Given what was presented at SVP yesterday, it's more than maniraptorans and more than fuzz! If Ornithomimids are already at stage 3, then stage 2 must be more primitive and stage one even further down the tree. Look at an ostrich feathers, and that's what the most primitive Maniraptoriformes had (and Sinosauropteryx feathers are actually pretty similar, just much tinier). So the origin of basally-branched filaments must be around Coelurosauria and the origin of simple fuzz must be down around Avetheropoda somewhere unless the stages evolved REALLY quickly once feathers appeared.

You've got it all wrong, I wasn't excluding non-manies, just that all manies had fuzz (and feathers) ok? Dose this make sense?

Ah ok, I thought you were saying you restricted that to maniraptors but not to non-maniraptors like tyrannosaurs.

Nope, I don't restrict dinofuzz within the Theropoda. But I don't think that dinofuzz existed in other Dinosaur groups, Such as Sauropods.

[Loxodon]

If you go back and actually look instead of assuming, you'd see I wasn't suggesting it did. I was merely asking Stargate if there's any other bigger dinos with feathers (since theres a size difference between the two) as I'm unaware of them. You budded in yourself and assumed. However, I do believe it'd be unlikely for bigger Dinosaurs to have feathers without reason. Which begs me to wonder what purpose a T rex would have with feathers
Even with that context, 2 meters is 1/5th of the animal...A very considerable amount

You are essentially saying that you are not claiming that the 2 meters would play a big role, and then going on to claim just that. You did the same thing before, so which is it? Do those 2 meters play a significant role, or do they not? I am not talking about how big a percentage of the animal's length it is, if an animal is already 10 meters long, if we are already talking about a very, very large creature, can you provide an explanation as to why those 2 meters would heavily influence the integument? If not, then Yutyrannus remains the best comparison we have, and feathers remain the default assumption. And as for what purpose feathers would serve on an animal the size of T. rex, there are many things it would have used them for. The first and most obvious is display, evolution is all about passing on your genes, and for this reason sexual selection is in many ways as or even more important than long term survival. But feathers would not affect long term survival negatively, anything but. As can be seen in modern birds such as ostriches, feathers function fundamentally different than fur. While fur is essentially a blanket on the body, helping to keep it warm, feathers are a far more complex structure, capable not only of heating an animal but also of cooling it. For a creature the size of T. rex, feathers may actually have helped prevent it from overheating.

Nope, I don't restrict dinofuzz within the Theropoda. But I don't think that dinofuzz existed in other Dinosaur groups, Such as Sauropods.

Why not? I mean sure, later more derived sauropods probably lost it in at least some lineages, but early members of the group, so-called "prosauropods", may very well have possessed at least some limited covering. I would not even be surprised if some later lineages retained it in certain regions purely for display, perhaps on the neck or tail, but this is of course pure speculation.

[Plasticbeast95]

Because there's no proof of any sauropod possessing dinofuzz. If you can find me proof, then I will be happy to believe you. 

[Loxodon]

Phylogenetic bracketing indicates that fuzz may be ancestral to all ornithodirans, or at the least all dinosaurs. If this is the case, early sauropods would have had fuzz no matter what, the real question is when or if they all lost it. My presumption would be that the majority of the covering was lost fairly early on, since primitive dinofuzz was more like fur than feathers, and as such may have been problematic for larger animals. On top of this though, I would speculate and say that it is not wholly unreasonable, though also not necessarily likely, that at least some lineages of more derived sauropods retained limited coverings of fuzz in some regions.