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Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms

Brusatte et al. (2010) Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms. Science Vol. 329. no. 5998, pp. 1481 - 1485.doi:10.1126/science.1193304

Tyrannosaurs, the group of dinosaurian carnivores that includes Tyrannosaurus rex and its closest relatives, are icons of prehistory. They are also the most intensively studied extinct dinosaurs, and thanks to large sample sizes and an influx of new discoveries, have become ancient exemplar organisms used to study many themes in vertebrate paleontology. A phylogeny that includes recently described species shows that tyrannosaurs originated by the Middle Jurassic but remained mostly small and ecologically marginal until the very end of the Cretaceous. Anatomical, biomechanical, and histological studies of T. rex and other derived tyrannosaurs show that large tyrannosaurs could not run rapidly, were capable of crushing bite forces, had accelerated growth rates and keen senses, and underwent pronounced changes during ontogeny. The biology and evolutionary history of tyrannosaurs provide a foundation for comparison with other dinosaurs and living organisms.

Should we try to find/create a new restoration for the Description area?

I've noticed some anatomical issues with the current image, such as shrink-wrapping, a snake-like tail, a strange, almost charcharodontosaur-esque head and human-like legs (that is to say they're extended in a position almost as it were standing completely erect ala Homo-genus homonids or Canis-genus dogs). I would propose replacing it with another, more scientific image, and moving the current image to the T.rex in popular culture article's header, but that's just me. In any case, I'd prefer a consensus to be had before relocating the image or not, just to be safe. --Paleontology is a wonderful thing. Shame many people outside of science don't understand the many dinosaurs aren't what they used to be. (talk) 02:59, 28 May 2013 (UTC)

I don't really see most of what you've listed. This isn't a hadrosaur, so the tail was bendable. "Shrink-wrapping" refers to restorations where the bones almost protrude through the skin, such as here[3], giving an emaciated appearance, and I don't see that either. Not sure what you mean by "charcharodontosaur-esque" head, the head here has a concave profile, whereas charcharodontosaurs are more convex. One leg is extended, yet flexed and not straight, so not sure what you mean by man-like. We have this[4] alternative, but the head seems a bit small there, and the tail too thin. FunkMonk (talk) 03:25, 28 May 2013 (UTC)

I agree with a few of those points. The leg musculature is clearly based on humans rather than theropods. Bulging thigh, big calf muscles only on the posterior of the leg. Looks like a human runner, not a drumstick. I think the main issue they seem to have is stylistic. Subtle things like the pose, snake-eye, drool, etc. make it seem a bit cartoonish or monster-like rather than naturalistic. It's a bit like using this restoration for Tiger [5] I'd be willing to update this for upload if it would be better [6] MMartyniuk (talk) 13:05, 8 August 2013 (UTC)

I think that would be good! Looks very heavy, yet with the right proportions. Just for the record, here's a link to the discussion at the image review, where I made a longer reply before seeing this:~[7] FunkMonk (talk) 13:19, 8 August 2013 (UTC)

I'll work on it a little and try to upload it today... full disclosure, there will be feathers ;) MMartyniuk (talk) 14:05, 8 August 2013 (UTC)

Haha, prepare for conspiracy theories about Wikipedia being controlled by the secret BAD cabal. FunkMonk (talk) 14:16, 8 August 2013 (UTC)

This is my first time commenting so I hope I'm doing this right. Considering there is no evidence that tyrannosaurus rex had feathers, let alone full body feathering, the fact that the only full body life restoration image of a Rex having feathers on its wikipedia page could be considered.. misleading. While the page does make it clear that some scientists hypothesize that it may have had feathers, either another non-feathered image should be presented or a 'disclaimer' should be put beneath the image reminding the viewer that there is no evidence supporting feathering, let alone full body feathering with such well formed feathers clearly beyond the "stage 1" point. In fact, just glancing at the Yutyrannus page, it seems that not only is it the largest known tyrannosaur to have feathers, but all larger species after it (or related, as it may have been an off shooting branch), including tyrannosaurus rex itself as stated on its own page, did not appear to have feathering. 108.15.86.215 (talk) 22:33, 14 August 2013 (UTC)

There is evidence of extensively feathered tyrannosaurs in formations that preserve feathers, but none against feathers, so it doesn't contradict fossil evidence, rather it reflects it. But I guess Dinoguy can put it more eloquently. FunkMonk (talk) 14:08, 18 August 2013 (UTC)

I've never heard of a single shred of evidence of Rex having feathers. To my knowledge the largest tyrannosaur found with feathers was yutyrannus, which is much smaller than the Rex. We also have skin impressions of Rex, or at least I thought we did, which show scales. So, yes, it really does contradict the evidence. 108.15.86.215 (talk) 20:41, 18 August 2013 (UTC)

Check this: http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Dinosaurs/Image_review#Tyrannosaurus FunkMonk (talk) 21:29, 18 August 2013 (UTC)

There's no evidence it had feather, there's no evidence it didn't have feathers. We have one skin impression, detached from the body, but probably from near the leg (where even modern birds have scales), the size of a playing card. That's not evidence of anything. We have a related species of the same size with full body feathers, and both more primitive and advanced lineages all have feathers. Saying there's no evidence T. rex had full body feathers is like saying there's no evidence Australopithecus had full body hair (see quote from Mark Norell in article). True, but pointless when it comes to restorations. It could equally go either way. If somebody else wants to do an accurate non-feathered restoration I wouldn't be necessarily opposed to presenting both, but I think the current evidence suggests a scaly T. rex is less likely and less scientific as it conflicts with phylogenetic bracketing (and, as discussed with sources in the Feathers section, so do most scientists who have addressed the topic). MMartyniuk (talk) 23:47, 18 August 2013 (UTC)

I'm mewrrently updating my Daspletosaurus to include feathers, this is a WIP version [8] (I'm probably going to remove some from the underside based on what I have read on the internet.) In Currie 2003 [9] there is a tarbosaurus that has been damaged by poachers, it has skin impressions that were found in the 'thoratic' region. The problem is that due to the damage it's not certain where they came from. The same paper also mentions that 'lighly pebbled' skin impressions are known from Gorgosaurus, Albertosaurus and Daspletosaurus but these arn't figured or described. I have just heard about patches of 'naked skin in Gorgosaurus and there is supposedly T.rex skin that resembles 'plucked chicken'. If patches of naked skin exist, then it seems plusable/probable based on phylogenetic bracketing that these areas would be covered in feathers in life. I found a forum page that summerises published and rumoured coelurosaur skin impressions but wikipeda claims it's on their 'spam list' so I can't link to it. Just search 'gorgosaurus skin impressions' in google, it's the third down. Steveoc 86 (talk) 12:49, 19 August 2013 (UTC)

I like your new version! I was just wondering whether the bumps and horns on the face would really be covered as well? Such are naked in modern birds, but I can't really see if they are too here, since I can't zoom in. FunkMonk (talk) 14:27, 19 August 2013 (UTC)

THe whole lightly pebbled skin = featherless, scale patches needs to be better supported, IMO. Once we get actual descriptions of some of the various pebbled/naked/plucked seeming skin patches, I have a feeling there will turn out to be significant overlap in these morphologies. Do have to agree on the facial feathers--there seems to be good evidence of face biting and head butting in tyrannosaurids, which would at least probably de-feather these areas during life, if they weren't born featherless there. MMartyniuk (talk) 14:45, 19 August 2013 (UTC)

In the above version I have illustrated the lacrimal, orbital and jugal horns as having no feathers on them. I don't mind pealing the feathers back from the head for the reason you mention. At some point I add this to the image review page. Steveoc 86 (talk) 12:00, 20 August 2013 (UTC)

• Just for the record, there is at least one modern restoration that shows a naked Tyrannosaurus in this article, the one by Luis Rey under locomotion. FunkMonk (talk) 05:33, 26 August 2013 (UTC)

The T-Rex restoration image is absurd. Even if the t-rex did indeed have feathers (which has yet to be proven), it certainly would not be covered in them.This scientist explains. Close relatives to the T-rex were found with a small amount of feathers.... but never the rex itself. You are making a bold leap that I would compare to.... putting long orange hair on all monkeys because you read about an orangutan. 76.16.108.117 (talk) 09:23, 13 September 2013 (UTC)

The article you link notes that close relatives of T. rex were fully covered in feathers, not that they had a "small amount" which is wrong. It notes that T. rex probably did have feathers but that we don't know for certain how extensive they were. A full covering is just as plausible as a sparse covering. Yutyrannus is the exact same size as most T. rex except exceptionally big specimens like Sue, and it is fully covered. It's still possible T. rex had only a few feathers. It's equally possible, as the article says, that it had a lot of feathers. The current picture is just one possibility in line with known evidence. If somebody were to create one with fewer feathers, that could be displayed as an alternate. But most scientists agree a restoration with zero feathers would be wrong. MMartyniuk (talk) 16:46, 13 September 2013 (UTC)

Also, I have to note that the scientist who wrote the article is wrong about wings. We know that Ornithomimus and possibly Concavenator had "wings" or pennibrachia (long feathers on the arms and hands), and these clearly could not fly. The evidence shows that wings evolved long before flight, possibly for display or covering nests. MMartyniuk (talk) 16:50, 13 September 2013 (UTC)

Sorry, you must have failed to read the same article that I linked. "This doesn't necessarily mean that T. rex itself had feathers, but it's a very reasonable guess. It also doesn't mean that T. rex had a full array of colourful feathers like a bird. It certainly didn't have wings, as there is no way it could have flown.

It might have just sported a reduced smattering of feathers, the same way that an elephant has a very thin coat of hair." In addition to the fact that the image may or may not be factual and is simply supposition, the image itself is of poor quality and appears as if someone took an existing image of a T-rex and applied a poor photoshop smear tool/filter over it. I would highly recommend replacing said picture, and if you are so adamant that the Rex had feathers, perhaps there exists another photograph with better quality. -Rob^talk 23:50, 3 October 2013 (UTC)

Either way, following current evidence, this restoration is more accurate than a naked version, but I guess discussion could be focused on the extend of feathers, that would be most productive. FunkMonk (talk) 23:54, 3 October 2013 (UTC)

• If we ever get a free photo of the Yutyrannus specimen, wouldn't it be a good idea to have it here under "Skin and feathers", to get the point clearer across? FunkMonk (talk) 23:08, 3 October 2013 (UTC)

Removed the Wooly Tyrannosaur. It really is rather ridiculous, both in OR (how would it shed body heat?) and in the bad photoshopping. — kwami (talk) 13:48, 20 November 2013 (UTC)

Saurischians and especially theropods have an extensive air sac system that would help thermoregulate.^[1,2,3] Birds today raise their feathers and and even shake their body at the same time to replace the air trapped by them.^[4] Feathers and fur aren't only heat traps as a steep temperature gradient works both ways.^{[5, 6]}

As for the commentary on MMartyniuk's work, the general stance here is that the images only have to have enough artistic merit to be accurate. If you want something you think is aesthetically better on the page feel free to be so bold as to do it yourself.

Dracontes (talk) 17:17, 20 November 2013 (UTC)

Indeed. I did do a relatively quick photoshop job on an out of date featherless restoration. Considering this was done for free, you get what you pay for ;) If I have time/inclination I can work on finer detailing in the future. MMartyniuk (talk) 17:39, 20 November 2013 (UTC)

"how would it shed body heat?" Gular flutter? Fluffing out the feathers to allow circulation? Via the naked skin patches? Modern birds have plenty of heat shed methods unavailable to large mammals but perfectly available to large birds, even hypothetical giant ones. MMartyniuk (talk) 21:11, 20 November 2013 (UTC)

Ok, I took a few minutes and whipped up a quick version with feathering at the minimum plausible extreme. Given that this is less feathering than the officially distributed pictures of the more basal Siats, this might satisfy everybody...? Nah ;) MMartyniuk (talk) 15:25, 22 November 2013 (UTC)

Actually, the minumum plausible extreme would be no noticeable feathers at all, but this seems like a reasonable compromise. — kwami (talk) 16:22, 22 November 2013 (UTC)

Good to me, but then again, the old one was as well, so let's see what everyone else thinks! FunkMonk (talk) 16:23, 22 November 2013 (UTC)

Maybe we could include both versions to show the two reasonable extremes for tyrannosaur integument? It would at least satisfy both crowds. Dromaeosaurus is best dinosaur (talk) 15:04, 26 November 2013 (UTC)

Seems like a good idea to me. If anyone feels up to it, a downy Tyrannosaurus chicken would be nice. While feathers in the adults is debatable, I don't think there's any real reason to doubt the smaller ones had some sort of insulating covering. Petter Bøckman (talk) 08:30, 28 November 2013 (UTC)

Based on what though? This is controversial in another way--the Nanotyannus debate. If Nanotyrannus is real, there are no known juvenile T. rex specimens. MMartyniuk (talk) 11:19, 28 November 2013 (UTC)

I think it's unneeded, we have one completely unfeathered one also, but we could maybe have one of a juvenile? FunkMonk (talk) 16:33, 28 November 2013 (UTC)

More subsections under Feeding strategies

The section "Feeding strategies" has been greatly expanded, but it is one huge chunk of continuous text, and it would help the reader if it was broken up into subsections. I can't even keep track on it. FunkMonk (talk) 02:01, 6 September 2013 (UTC)

I think that would be a good idea. DinopediaR (talk) 05:30, 7 September 2013 (UTC)

Also, remember italics for binomials and genus names! Good work, in any case. FunkMonk (talk) 06:55, 7 September 2013 (UTC)

Thank you. I will do my best. DinopediaR (talk) 03:24, 8 September 2013 (UTC)

It is getting very long, perhaps it should be a spin off article? "Tyrannosaurus feeding behaviour" or some such? FunkMonk (talk) 13:56, 23 November 2013 (UTC)

T. rex charge.jpg

Who added that image? The skull shape and musculature are bizarre, it's eye is huge, and do we really need another "reconstruction" on the page, in the same section no less? — Preceding unsigned comment added by Tomopteryx (talk • contribs) 04:22, 9 September 2013 (UTC)

Removed it before I saw this. FunkMonk (talk) 15:30, 14 September 2013 (UTC)

It's done either way, so all good. — Preceding unsigned comment added by Tomopteryx (talk • contribs) 13:20, 20 September 2013 (UTC)

Any volunteers?

Looking at the page's edit history, there has been a lot of recent disagreement over what appears in the description for Matt's reconstruction. It's currently set to "Restoration of T. rex showing hypothetical feathery coating, as implied by phylogenetic bracketing." If this is what you want, I'm fine, that's all well and good.

The question is, if this is the way we are going, who is going to volunteer to go and add "showing hypothetical scaly coating" to every single reconstruction on the pages for carnosaurs, megalosauroids, coelophysoids, plateosaurids, pachycephalosaurids and every other clade that we don't have direct impressions from?

At least Tyrannosaurs is in a solid bracket. — Preceding unsigned comment added by Tomopteryx (talk • contribs) 12:32, 16 November 2013 (UTC)

Yeah, this is getting kind of ridiculous, really. A feather coat for T.rex is about as likely as a furry coat for Panthera leo atrox these days; I still don't see why it's "hypothetical" to add feathers but not so to add scales. Maybe a preservation bias? ;P Dromaeosaurus is best dinosaur (talk) 13:29, 20 November 2013 (UTC)

It's about as likely as a furry coat for an elephant or a rhino. Yes, bracketing implies that Rex had feathers, but plumaceous, not pennaceous as you have them, so the image is quite definitely OR, and based on current evidence is most likely wrong. And the fact that the lineage had feathers does not mean that every member was covered with them, especially the larger ones. They could have hatched as downy chicks, but lost them as they grew, or perhaps retained them in certain spots for display. But what you have looks like it's prowling the Arctic tundra. — kwami (talk) 20:49, 20 November 2013 (UTC)

"But what you have looks like it's prowling the Arctic tundra." It's actually based on the feathering of emu and cassowary, which prowl humid tropical forests and the Australian outback, respectively. But out are aware that Tyrannosaurus rex remains are also reported from the Cretaceous arctic, right? If I prowled the Outback in a cloak of emu feathers (a bird which weighs almost as much as I do), I would quickly die. Being a mammal, with a completely different system of respiration, ventilation, and integument, as are elephants and rhinos.

What is the precedent for any feathered animals losing feathers as they grow? This strikes me as baseless speculation. At what point in tyrannosaur growth do you suppose the feathers were lost? Why are they ok in chicks but not say, horse-sized or bison-sized individuals? (Because chicks are supposed to be "cute", maybe, and it is not ok for a predatory dinosaur to resemble something cute and funny instead of a sci-fi monster?) The feathers as depicted are intended to be plumulaceous, like those of basal tyrannosauroids, ratites, compsognathids, and ornithischains, not pennaceous. The depiction I uploaded is representative of one plausible extreme. If somebody would like to produce a scientifically plausible restoration closer to the other extreme, I'm all for it. But right now as far as I can see, mine is the only one within the plausible range.MMartyniuk (talk) 21:03, 20 November 2013 (UTC)

The speculation I've seen is that the larger dinosaurs in warmer climates probably did not have insulating coats. There are also no extant birds anywhere near the mass of Rex. (Even Yutyrannus was only 20% the mass of T. rex, and AFAICT it lived in a colder climate.) Speculation by those in the field carries weight, since all reconstructions are speculative. They could very easily be wrong, and perhaps none have thought to consider the difference between mammals and birds, but we don't get to speculate on our own, not in the article.

No precedent, just speculation by paleontologists that just because an animal is too large to sport feathers as an adult doesn't mean they didn't have them when young. Anyway, that's irrelevant here as we're not depicting young.

Deinonychus may well have been fluffy. It's not a matter of cute, it's a matter of the ratio of surface area to volume and the resulting efficiency of heat loss or retention.

Ratites have pennaceous feathers (the defining feature being a central vane, not barbules), and what you have on Rex looks a lot like ostrich feathers. Those are not supported by evidence from tyrannosaurids or anything more basal than tyrannosaurids. They're also 5× as long as the 20 cm of the longest known feathers on Yutyrannus. — kwami (talk) 21:35, 20 November 2013 (UTC)

Minor point, but should be corrected. Pennaceous feathers are known as basally as Sinosauropteryx (see citations in the Wiki article) and soon to be published ornithischian. They appear to be basal to Dinosauria at most and Coelurosauria at least. Reports that these are plumulaceous seem to be based on taphonomic distortion. Usage of pennaceous/plumulaceous is applied inconsistently in literature, down feathers are often described as plumulaceous despite having a weak central rachis. Sinosauropteryx feathers are reportedly similar to modern down on close inspection. MMartyniuk (talk) 13:29, 21 November 2013 (UTC)

The largest birds we know of (recently extinct elephant birds, moas, Haast's Eagle, etc.) definitely had dense feather coats. Not the size of Tyrannosaurus, obviously, but we have no evidence of any kind of large, naked bird. As for new restorations, I think the current one works, but discussion of feather type and extent is probably alright in any case. FunkMonk (talk) 22:26, 20 November 2013 (UTC)

We have nothing to compare a tyrannosaur to, so anything we postulate is simply speculation. Many paleontologist have assumed that, like large mammals, they would have had sparse or localized feathering if they had any at all. They may well be wrong, of course; Yutyrannus was a surprise. But what little data we have suggests that T. rex was not feathered to the extent of Yutyrannus. That's the best info we have at present, and it flatly contradicts this image. Thus the image is unabashed OR, and as such has no place in an encyclopedia. — kwami (talk) 10:14, 21 November 2013 (UTC)

Most of the life restorations we post contain speculation and are to varying degrees OR, they have to. That said, there are publications that mention that tyrannosaurs might have had a mix of feathers and scales. The best we can do is follow whatever evidence is available, skeletal proportions, skin impressions and phylogenetic bracketing. With Tyrannosaurus all we know is that some parts of it's body had small patches of ~2mm scales and it is nested within a group covered in feathers. At this point in time you can illustrate Tyrannosaurus mainly covered with feathers, mainly covered with scales, or anywhere in between and they can all be supported. No one mentioned anything when we posted pictures of feathered ornithomimosaurs which at the time didn't have clear skin impressions nor did anyone mention anything with depictions of feathered Therizinosaurus, why just Tyrannosaurus? An easy fix is to have a second restoration showing mainly scales and possibly naked skin with a caption along the lines of, 'a restoration of Tyrannosaurus showing scales as implied by skin impressions'. That would show to the casual viewer both extremes and that it's not certain what type of covering Tyrannosaurus had. Steveoc 86 (talk) 13:09, 21 November 2013 (UTC)

That would be a good idea. About this specific image, though, it shows T. rex as being five times as fluffy as Yutyrannus, when the fossil evidence is that it was less. And do we have no artistic renditions done under the supervision of someone who works on these animals that we could use for guidance? — kwami (talk) 13:33, 21 November 2013 (UTC)

Another thing to note is that Late Maastrichian North America was likely quite like China; the receding sealines show that it was actually getting colder near the end of the Cretaceous (and thus the poles were likely forming), meaning China likely wasn't the only tundra-dominated area in the world. And I'm pretty sure ratite feathers aren't truly pennaceous, but some sort of basal form of pennaceous (they do lack the shaft of a cardinal-like feather, IIRC) which, considering ratites are among the more basal birds. (Anseriformes are the first branch of crown Aves to appear, considering Vegavis is from 65.5 mya, right about the end of the Cretaceous, though galliformes, penguins, charadriiformes, anseranatids, anhimids and dromornithids all also arose at that time, so crown Aves sort of exploded in diversity at the end of the Cretaceous) In any case, most of the T.rex range likely was tundra, so a extensive feather coat (aside from underbelly and possibly the legs) isn't far-fetched. Dromaeosaurus is best dinosaur (talk) 14:49, 21 November 2013 (UTC)

Where does the idea come from that Cretaceous China was a "tundra"? The fossil plant evidence is unequivocal that the Yixian Formation was temperate and dominated by dense ginkgo and conifer forests, and seasonally cool and arid (meaning it had an autumn cold and dry enough for some degree of snowfall). Theclimate would have been similar to the US mid-Atlantic. I've never heard Washington, D.C. described as a tundra... MMartyniuk (talk) 15:59, 21 November 2013 (UTC)

I didn't mean that Yutyrannus lived in tundra, but rather that our rendition of T.rex makes it look like a wooly mammoth. — kwami (talk) 01:26, 22 November 2013 (UTC)

Elephants have peculiar precedents. There is in Rhinocerotidae a tendency to develop semi-aquatic forms such as Rhinoceros, Metamynodon or Teleoceras. Being ostensibly hairless isn't the end of the story: these animals still have to thermoregulate behaviorally, wallowing/bathing in water/mud/dust and being active in the most amenable parts of the day and seeking cover at other times. I'm not sure large mammals outside of those lineages would necessarily resort to these or other adaptations let alone dinosaurs. Birds have generally pretty thin skin under the feathers and at least Santanaraptor's preserved skin hints at a similar state of affairs for coelurosaurs.[1,2]

You must surely have sharper sight that any of us to be able to discern the texture of the feathers in MMartyniuk's rough digital paint over.

"the fact that the lineage had feathers does not mean that every member was covered with them, especially the larger ones."

I don't think you quite understand how scientific inference in general and phylogenetic bracketing in particular work. While what you said is a good caveat to have in mind, what the evidence we have says is that an extensive covering is more likely than limited tufts (which says nothing about their length). Then there is also the phylogenetic signal: we have several small mammals that manage being mostly naked (armadillos, warthogs) and no bird. Theropods at least were more like birds than mammals. Beyond that speculating without further testing is indeed baseless.

As for authoritative speculation here is...

• Xing Xu:[3]

"Based on the presence of feathers in some extinct coelurosaurs and all living birds, this approach suggests that all coelurosaurs, with the possible exception of gigantic species such as Tyrannosaurus rex, are feathered."

• Thomas Holtz, Jr:[4]

"The evidence has been mounting that the big tyrant dinosaurs were descendants of fuzzy dinosaurs, and quite possibly fuzzy themselves"

• Paul Sereno:[4]

"In my lab, I have a T. rex fossil that shows the beast did not have scales,”(...). “But it’s only in China that we have the opportunity to see evidence of what replaced scales – feathers! The report is a red flag to Hollywood and some scientists who get wobbly legs thinking something as ferocious as T. rex might have been packaged with a soft downy overcoat. You’ll now be able to date any Hollywood film that does not give these brutes their feathery due!"

• Lindsay Zanno:[4]

"[Yutyrannus] doesn’t put the nail in the coffin on the debate over the body covering of T.rex, but it definitely weakens the argument that the tyrant-king couldn’t have had feathers,"

I get this impression you didn't read the papers I posted at the top of the talk page. Here is the pertinent bit:

"Saurischians and especially theropods have an extensive air sac system that would help thermoregulate.^[1,2,3] Birds today raise their feathers and and even shake their body at the same time to replace the air trapped by them.^[4] Feathers and fur aren't only heat traps as a steep temperature gradient works both ways.^{[5, 6]}"

The point with the mention of the air sac system is that it obviates the square/cube rule by providing extensive internal evaporative surfaces which the 3rd ref shows are more efficient at dissipating heat than the skin itself when the ambient temperature is the same as the internal one.

Also I think you're assuming by a peculiar default that the average temp estimated for that time would be a constant measurement. I live in a subtropical climate (Southern Portugal): winter is definitely cold, especially the nights.

Dracontes (talk) 19:34, 21 November 2013 (UTC)

The point about air sacs is an important one. However, your ref notes that the idea that large dinosaurs might have lost their feathers is a common one among paleontologists. It also does not give much support for our rendition. Xu says Yu's feathers may have been a winter coat, not shared with more familiar tyrannosaurs. Witmer calls Yu a "woolly tyrannosaur" and says there has been some "rather sketchy" evidence that Rex was not feathered. Sereno says that Rex might have been covered with a "soft downy overcoat". But that's not what we show. The article says in both the lead and body that the feathers were simple filaments. Our pic looks like they're intended to be vaned, pennaceous feathers like an ostrich has.

The small hairless mammals you note are burrowers. Birds may take advantage of existing burrows, but they don't burrow themselves. That's a likely explanation for the difference.

You don't need sharp eyes. Just measure the length of the feathers in silhouette, and compare to the length of the animal. The result is one tenth; for a 9m adult, that's 5× the 20cm max of Yutyrannus. If our image had showed T.rex with 20cm feathers, I would never have objected to it. — kwami (talk) 01:19, 22 November 2013 (UTC)

Actually, Maloney and Dawson state that longer feathers, especially those that those that fade to a white colouration proximally, are actually better at keeping an animal cool than shorter feathers, so arguments on them being too long are pretty unfounded. Ref: Shane K. Maloney, Terence J. Dawson (1995) "The heat load from solar radiation on a large, diurnally active bird, the emu (Dromaius novaehollandiae)" Journal of Thermal Biology Volume 20, Issue 5, October 1995, Pages 381–387.

Irrelevant now anyway as MMartyniuk has put up an excellent new reconstruction. User:Tomopteryx

"Might" is the operative word.

If you look closely at what I wrote you'll see I said "texture". What I saw on the earlier version was brushwork with little detail. If those were pennaceous or plumulaceous feathers was rather left to one's imagination. But now as Tomopteryx said it's moot. Though perhaps the lead needs to be updated according to Foth 2012¹ since he makes a cogent argument preserved feathers found so far in non-avian coelurosaurs are rather difficult to characterize regarding their structural details: crushed feathers look filamentous even if they are indeed pennaceous.

"Birds may take advantage of existing burrows, but they don't burrow themselves."

Birds do burrow to construct nests (see puffins, bee-eaters, etc). Conversely not all mammalian tropical burrowers are without pelage (marsupial mole, golden mole just to exemplify the obligate ones).

From what literature I've read recently, it's not nearly as simple a story as people would make it just based on physical principles. Here are a few enlightening papers on the thermoregulatory importance of integument: [2] [3]. Dracontes (talk) 00:45, 25 November 2013 (UTC)

• By the way, there are tonnes of restorations of fully feathered Deinocheirus and Therizinosaurus, which are as large as T rex, but no one seems to bring forth the "too large for feathers" argument there, probably because they are so bird like already. By the way, couldn't some kind of compromise be agreed upon for this image? I guess if the longest feathers were shaved a bit here and there that there would be less scepticism? FunkMonk (talk) 17:05, 21 November 2013 (UTC)

I've said several times I would be fine with an image closer to the other reasonable extreme. I just don't have time to work on it at the moment. The current image is CC-By--have at it! MMartyniuk (talk) 18:24, 21 November 2013 (UTC)

I guess it's up to the dissenters to give a clear idea of what their vision is then! FunkMonk (talk) 18:30, 21 November 2013 (UTC)

That's too much, the point is just to show feathers, the extend isn't really that important. FunkMonk (talk) 16:24, 26 November 2013 (UTC)

Edit request

Image caption reads: "Edmontonia and a cast of the "Stan" specimen, Houston Museum of Natural Science" The fossil is not a cast of "Stan" but is a real-bone fossil named "Wyrex" 204.2.212.62 (talk) 19:25, 21 November 2013 (UTC)

Not done: please provide reliable sources that support the change you want to be made. How can someone verify the correctness of your statement? Thanks, Celestra (talk) 02:11, 22 November 2013 (UTC)

Or one could accept the challenge and check it out for oneself ;-) This newspiece^[1] does have this paragraph:

"The hall’s dramatic Cretaceous display, with its triangle of Tyrannosaurus rexes, is particularly impressive. Wyrex, a 10-foot T. rex with the most complete set of hands ever discovered, spars with a Denversaurus, a squatty plant eater. Across the room, a slightly bigger T. rex, Stan, clashes with Lane, the only triceratops ever found with fossilized skin. And then there is the gawky teenage T. rex, Bucky, which lurches toward the nest of two giant pterosaurs."

The pose of the mount identified as Wyrex at the top is the same except for the head (and both look similar at that) and as Denversaurus was sunk into Edmontonia I think the edit requester does have a point.

Here is another photo^[2] taken from a similar vantage point and suitably identified. There's a museum handout associating Wyrex with Denversaurus.^[3]

Finally compare this photo of Stan with the mount mentioned. I think various differences are apparent between the specimens. Dracontes (talk) 21:53, 26 November 2013 (UTC)

Fixable, I totally misread the request. FunkMonk (talk) 21:56, 26 November 2013 (UTC)

Semi-protected edit request on 31 December 2013

On the page about Tyrannosaurus, I would like to change an incorrect fact. Sue, the largest specimen of Tyrannosaurs, was actually 42 feet long and not 40. I would like it if you would please change that. NCharizard25 (talk) 23:35, 31 December 2013 (UTC)

Not done: please provide reliable sources that support the change you want to be made. The 40-foot length is backed up with a source. NCharizard25, you'll need an equivalent or better source that says it was 42 feet long to change it. —C.Fred (talk) 23:40, 31 December 2013 (UTC)

"4m tall at the hip"

I know this little detail has been referenced to the field museum for a long time but they have been wrong about the dimensions of their own mount before (claiming Sue's length to be 12.8m when it actually was 12.3m) and they are certainly wrong here too, as evidenced by this image provided by the team that published Hutchinson et al. (2011), there you can see that the actual mounted skeleton only reaches 3.7m at the hip even when having its legs arranged in an unnatural columnar position. Saying that Sue was 4m tall at the hips is factually incorrect but since there isn't any reliable source explicitely stating it, should it be removed or should it stay until a publication explicitily corrects the field museum again? (after Hutchinson et al. 2011 was published the field museum changed Sue's listed length to 12.3m). Mike.BRZ (talk) 07:19, 1 January 2014 (UTC)

According to Scott Hartman, the height at the hip of the tallest T.rex (A.K.A Sue) was about 3.4 m in a normal position, While according to this image Sue is 3.93 m tall with not stretched legs:

http://www.rvc.ac.uk/SML/Projects/3DTrexImages.cfm

The tallest point at the hips is 7.2 cm long in the image, while the femur is 2.4 cm and in real life its 1.312 m long. making this calculation 1.312/2.4= 0.546666667(7.2)= 3.93 m, but I agree that we should not include the field museum figure in this page, since its reliability is as good as that of the 12.8 m figure.--Dinoexpert (talk) 00:57, 10 January 2014 (UTC)

I recommend you use an image editing software, like GIMP, so you can measure the pixels, is a lot more precise. In the image, every square of the metric grid is 127px by 127px, the skeleton of Sue is 469px from the lowest to the tallest point, so 469/127= 3.69m and those legs are as stretched as is possible, in fact to arrange theropod legs like that you have to break them. Mike.BRZ (talk) 03:13, 10 January 2014 (UTC)

But that would clearly be original research, with a little bit of synthesis, neither of which are ever allowed on Wikipedia. - Arjayay (talk) 19:52, 10 January 2014 (UTC)

Of course, I'm not saying "put 3.7m or less instead" but just remove the 4m claim since we know is wrong but yeah, that answers my question "should it be removed or should it stay until a publication explicitly corrects the field museum again?", thanks. Mike.BRZ (talk) 21:26, 10 January 2014 (UTC)

The scale bar is not accurate, the yielded length for the skeleton using the bar is less than 12 m, the skull length results 1.32, and the femur 1.28 m so the 3.7 m is not that accurate. I recalculated its height and resulted in 3.8 m, however, the metatarsals are a bit crouched, this makes the height a bit less.--Dinoexpert (talk) 21:41, 10 January 2014 (UTC)

That's because the 12.29m measurement is axial length, following the vertebral column, not straight line, there's nothing wrong with the scale of the images but this is getting offtopic (how to make the article better). Mike.BRZ (talk) 22:02, 10 January 2014 (UTC)

I still get 3.8 m using the squares, also 12.3 m total length, a length of 1.43 m long in skull (premaxila-quadratoyugal) length, and 1.525 in maximum length, this means my measurements are correct, I got 3.82-3.85 m tall at the hips.--Dinoexpert (talk) 23:06, 18 January 2014 (UTC)

Semi-protected edit request on 5 January 2014

On the Tyrannosaurus page, Sue is actually 42 feet. Here's my proof:
http://www.factmonster.com/ipka/A0878226.html
http://fieldmuseum.org/happening/exhibits/sue-t-rex
http://fieldmuseum.org/sites/default/files/Sue%20Fact%20Sheet.pdf
I hope that is enough information for you. I have been studying her and all Tyrannosaurus's for a long time. I know that she was 42ft long.

NCharizard25 (talk) 22:27, 5 January 2014 (UTC)

Thank you for your request. The problem appears to be that different sources give different lengths. Even the Field Museum cannot agree how long Sue is, here they say she is 40.5 feet, not 42 feet, so they contradict themselves.

Reading the detailed scientific paper here it says "However Sue's tail is reconstructed beyond the 27th caudal". As the end of her tail has had to be reconstructed, no one will ever know exactly how long she was.
As there is a contradiction between the sources, I think we need to keep both in, so have altered the article to say she was between 40' and 42'.
Arjayay (talk) 10:38, 6 January 2014 (UTC)

The fact of the matter is that the mounted skeleton of Sue is 12.3m in axial length as demonstrated by Hutchinson et al. (2011) this is no estimate, this was derived from the 3D model they made based on laser scanning the whole thing, it doesn't matter that the field museum used to or still claims their skeleton is 12.8m, it is a fact that their mounted skeleton is not and never was that long. Mike.BRZ (talk) 20:43, 6 January 2014 (UTC)

I always get nervous of people claiming "the facts" or "the truth", especially as the benchmark at Wikipedia is verifiability, not truth.
The longer length is verifiable in publications by Sue's owner, but I included both lengths, with citations, so the reader can make their own assessment.
You have stated "it is a fact that their mounted skeleton is not and never was that long", could you please cite a reliable source for this statement, avoiding any original research or synthesis. Thanks. Arjayay (talk) 08:58, 7 January 2014 (UTC)

[10] Ihardlythinkso (talk) 16:08, 7 January 2014 (UTC)

I already mentioned it, Hutchinson et al. (2011), available on the open access scientific journal PLOS One and already cited in the article. The Field Museum never even claimed to have measured the mount, they just claimed it was that long probably because measuring an skeleton that big is hard, the only attempt at actually measuring the thing before Hutchinson et al. (2011) was from Henderson & Snively (2004) by means of tape measure, they measured it at 12.01m, however, measuring by laser scan is inherently more accurate thus 12.29m is the most accurate measurement there is.

Museums have something to gain by claiming they have the biggest of the big, visitors. There's museums claiming Arizonasaurus was 7m long when the only fossils we have indicate animals about 3m, the BHI claims Stan is 12.2m long when as demonstrated by Hutchinson et al. again is only 11.8m and that is with a tail reconstructed even longer than Sue's which shouldn't be the case (Scott Hartman), the MOR claims MOR 008 is the longest T. rex skull there is but if you see it and you have at least a little knowledge of T. rex anatomy you see that is horribly put together and stretched on purpose.

So who do you believe in? a scientific paper where the skeleton was measured in the most accurate way possible? or the claims of a museum that has something to gain by making exaggerations? If you still want to include the longer length make clear that is a guesstime/claim by the museum but that the mount has been measured at 12.01m by tape measure and 12.3m by laser scan. Mike.BRZ (talk)

I think you're reading too much into this. The Field museum web site on Sue was created after the mount went up in the 1990s and has probably had template-based facelifts since then, but I sincerely doubt there is somebody curating that thing to ensure it's up to date with continued research like Hutchinson. Web sites of non-profit organizations are not the best sources for up-to-date minor adjustments to measurement details. The museum probably will require a grant to update the data on the plaques next to the skeleton, let alone remember/bother to do so on the site. When it comes to minor details like a few tenths of a meter, it's probably not worth the money for them to even bother with it. Note that the date on the linked pdf source is 2008, six years ago and 3 years prior to Hutchinson's study. Out of date, plain and simple. MMartyniuk (talk) 20:51, 7 January 2014 (UTC)

You are right, I've judged too harshly the Field Museum and I had forgotten about the logistics of making this kind of changes, I did come off as saying they are "lying" in purpose (the same goes for my question above) so I'll change my argumentation to something more level headed. Their claimed lengths and heights are guesstimates and for good reasons and like you said, if all of their site isn't up to date (there's some sections were they do list 40.5ft) is not because of some vested interest is just because overall such change isn't such a big deal, however museum guesstimates are not in the same league as direct measurements with method given found in the literature, so it'll be better if we follow what is found there and not in the website of the Field Museum. Mike.BRZ (talk) 06:01, 8 January 2014 (UTC)

More than 30 specimens?

This article mentions only 30+ specimens, while according to the theropod database there are just over 50+, this needs to be edited.--Dinoexpert (talk) 23:01, 18 January 2014 (UTC)