Tyrannosaurid skin impressions

[stargatedalek]

No one really knows if it had feathers or quills. But for the movie it looks like they were trying to portray quills.

It absolutely had feathers. It was a Coelurosaur. "Quills" are only known from Psittacosaurus, it's silly to suggest a theropod, let alone a Coelurosaur, had them instead of what its relatives had.

[WarrenJB]

It absolutely had feathers. It was a Coelurosaur.[/quote]

How quickly we forget the subject of this thread.

We can theorise about what integument it had. We can extrapolate with what we know about theropod morphology, physiology, environment and phylogenetic bracketing. We can say that it most likely had feathers, without many batted eyelids. Until someone discovers an Ornitholestes fossil preserved in suitably fine limestone or whatever, with the telltale fuzzy halo, we can't say it 'absolutely' had feathers.

[HD-man]

Yes, I don't think a coelurosaur would have a beak if there's nothing to support it having one, e.g. the appropriate bone structure.  However, mammal faces are pretty specialised as well, and they seem to be a worse point of comparison than birds for beakless coelurosaurs.  Most mammals have a specialised fleshy nose, the rhinarium.  If my understanding is correct, mammal facial tissue can also allow it to be moved, such as to pull back lips and expose teeth, which is impossible for reptiles and birds to do as they don't have this tissue.  Maybe mammal whiskers are related to the rhinarium, or other mammalian facial features?  I get the impression the snouts of beakless theropods wouldn't tend to be almost completely covered in feathers in the way that mammal snouts tend to be almost completely covered in hair.  For a start, that integument arrangement in mammals seems to be affected by the rhinarium.  There's also specimens of Sinosauropteryx and Sinornithosaurus that show their head feather covering stopping a large distance away from the nostrils.  I get the feeling that in beakless theropods, a significant amount of the snout would be covered in either scales or hardened skin.

In retrospect, I should've clarified that I wasn't necessarily arguing that basal coelurosaurs had mammal-like facial whiskers, just that they may have had facial whiskers where modern birds have beaks.

I'm not seeing anything on the WWD Ornitholestes that could be interpreted as a sparse covering of feathers over the entire upper body.

They're the small black-&-white horizontal lines along the neck, back, & tail of WWD's Ornitholestes concept art. In retrospect, the graininess of that image makes them hard to see. So just imagine the small Ornitholestes in the following image w/more tail feathers. That's basically what I was suggesting for Juravenator.

[Sim]

All of this really depends on where one chooses to draw the line on what constitutes a "beak". Most expert paleontologists (which is to say the two maybe three who've ever commented on it) agree that a "beak" is "a keratinous structure covering an animals jaws and gums" instead of "a keratinous structure on the animals face or jaws" but as far as the vernacular is concerned such a distinction is only going to serve to confuse people and lead to misconceptions. When someone says "Ichthyornis didn't have a beak" (because the gums weren't covered by keratin) that's going to lead people to assume it had a lizard-like or even "stereotypical-theropod-like" (overhanging teeth, etc.) face when it actually had a structure of keratin on its face that would have looked near identical to those of modern birds.

And then you have groups like cephalopods, puffer fish, and turtles, which are typically referred to as possessing "beaks" but wouldn't fit the definition either if Ichthyornis doesn't.

A structure of hardened skin or keratin on the animals face is more or less plausible on any dinosaur. We see a very toned down version of this on crocodilians, and the logical extreme of this adaptation in birds.

Ichthyornis did have a beak, it was on toothless areas on the front of its jaws.  The following is from the Ichthyornis Wikipedia page:

Ichthyornis is perhaps most well known for its teeth. The teeth were present only in the middle portion of the upper and lower jaws. The jaw tips had no teeth and were covered in a beak. The beak of Ichthyornis, like the hesperornithids, was compound and made up of several distinct plates, similar to the beak of an albatross, rather than a single sheet of keratin as in most modern birds.[3] The teeth were more flattened than the rounded teeth found in crocodilians, though they became wider towards the base of the crown. The tips of the teeth were curved backward and lacked any serrations.[1]

Funnily enough the reference [3] is called: "Marsh was right: Ichthyornis had a beak"

There's also this Dinogoss blog post which mostly focuses on the beak of Hesperornis, but also refers to the beak of Ichthyornis: http://dinogoss.blogspot.co.uk/2011/04/youre-doing-it-wrong-birds-with-teeth.html

I imagine the beak of Ichthyornis looked a lot like the beak of Hesperornis, due to the similarities in their beak correlates.

I don't think the WWD Ornitholestes is supposed to have feathers. I've always thought they were quills. I don't see why people would think they are weird. I've never heard anyone complain about how they look weird on Psitacosaurus.

Well, there actually is evidence for what Psittacosaurus has.  I think the integument arrangement of Psittacosaurus IS weird.  It contrasts with the many other different types of integument arrangements known for non-avian dinosaurs.  I can see the filaments of Psittacosaurus making sense as a large display structure in a small ceratopsian.  Psittacosaurus doesn't have the large display structures that are the frills in more 'derived' ceratopsians, so perhaps the long tail filaments were an alternative display structure?  In contrast, there is no evidence for any kind of theropod being almost entirely scaly with small areas of feathers/quills, and the feathers/quills of these kind of theropod reconstructions tend to look meagre.

[Newt]

Who says birds don't have whiskers?

[Neosodon]

In contrast, there is no evidence for any kind of theropod being almost entirely scaly with small areas of feathers/quills, and the feathers/quills of these kind of theropod reconstructions tend to look meagre.

There is fossil evidence suggesting Concavenator may have had quills on its arms.
https://en.wikipedia.org/wiki/Concavenator

[Arioch]

In contrast, there is no evidence for any kind of theropod being almost entirely scaly with small areas of feathers/quills, and the feathers/quills of these kind of theropod reconstructions tend to look meagre.

There is fossil evidence suggesting Concavenator may have had quills on its arms.
https://en.wikipedia.org/wiki/Concavenator

Those are heavily questioned, if not outright debunked by now. The forearm knobs seem to be just muscle attachment scars.

[Neosodon]

In contrast, there is no evidence for any kind of theropod being almost entirely scaly with small areas of feathers/quills, and the feathers/quills of these kind of theropod reconstructions tend to look meagre.

There is fossil evidence suggesting Concavenator may have had quills on its arms.
https://en.wikipedia.org/wiki/Concavenator

Those are heavily questioned, if not outright debunked by now. The forearm knobs seem to be just muscle attachment scars.

Not necessarily. It was questioned but quills are still a well excepted possibility.

"They identified the insertion point for the major arm muscles, and determined that the row of bumps could not have been located between any of them. They found that the only possibility was that the bumps could be an attachment scar for the M. anconeus muscle, which is unlikely, because this muscle normally attaches to a smooth surface without marks or bumps on the underlying bone, and argued that the most likely explanation for the bumps was their initial interpretation as feather quill knobs. The authors admitted that it was unusual for quill knobs to form along the posterolateral surface of the bone, but also noted that the same arrangement is found in some modern birds, like the Moorhen."

[HD-man]

Who says birds don't have whiskers?

No 1 in this thread AFAIK.

[stargatedalek]

Whether or not Concavenator had quill knobs it's silly to suggest that means it only had quills on its arms.

Quill knobs are associated with the shafts ("quills") of proper pennaceous feathers, not porcupine quills, not "proto-feathers", and not "whatever the Psittacosaurus things fall under". If Concavenator had quill knobs, than it had proper feathers, and likely not just on its arms.

[Neosodon]

Whether or not Concavenator had quill knobs it's silly to suggest that means it only had quills on its arms.

Quill knobs are associated with the shafts ("quills") of proper pennaceous feathers, not porcupine quills, not "proto-feathers", and not "whatever the Psittacosaurus things fall under". If Concavenator had quill knobs, than it had proper feathers, and likely not just on its arms.

We don't really know the relation between quills and feathers. Quills do not prove nor disprove feathers. I never heard anything about the suspected quills on Cocavenator having any relationship to pennaceous feathers. Post a link if you have one.

[stargatedalek]

Whether or not Concavenator had quill knobs it's silly to suggest that means it only had quills on its arms.

Quill knobs are associated with the shafts ("quills") of proper pennaceous feathers, not porcupine quills, not "proto-feathers", and not "whatever the Psittacosaurus things fall under". If Concavenator had quill knobs, than it had proper feathers, and likely not just on its arms.

We don't really know the relation between quills and feathers. Quills do not prove nor disprove feathers. I never heard anything about the suspected quills on Concavenator having any relationship to pennaceous feathers. Post a link if you have one.

You already quoted it yourself, "quill knobs" are only known from wings. Velociraptor, moorhen, etc., to suddenly expect them to be associated with "Concavenators magical spikey spikes" instead of feathers just because it isn't a traditional winged theropod is silly. We would see quill knobs on porcupines and the like if they were associated with "quills", but they aren't, they're associated only with bird (and Velociraptor) wings.

You're getting caught up on the wordage. "Quill" can mean many things. Traditionally it refers to the shaft of a feather, which is absolutely the only thing associated with "quill knobs", but quill can also mean "a hollow shaft", or even just "a long hard-ish spikey thing". Quill knobs are only, and I mean ONLY, found associated with pennaceous "bird styled" wings, and even then they're very rare. No quill knobs have ever been found on Psittacosaurus, Tianyulong, porcupines, scorpionfish, iguanas, frilled lizard frills, pufferfish, or any other "spiney/quilled" animal.

If the structures on Concavenator are quill knobs, than either this is evidence of remarkable convergence and Concavenator is actually a part of a coelurosaur lineage, or true shafted feathers evolved much earlier than generally believed (and the latter is highly unlikely given their late appearance within coelurosaurs).

[Sim]

In contrast, there is no evidence for any kind of theropod being almost entirely scaly with small areas of feathers/quills, and the feathers/quills of these kind of theropod reconstructions tend to look meagre.

There is fossil evidence suggesting Concavenator may have had quills on its arms.
https://en.wikipedia.org/wiki/Concavenator

Those are heavily questioned, if not outright debunked by now. The forearm knobs seem to be just muscle attachment scars.

Not necessarily. It was questioned but quills are still a well excepted possibility.

"They identified the insertion point for the major arm muscles, and determined that the row of bumps could not have been located between any of them. They found that the only possibility was that the bumps could be an attachment scar for the M. anconeus muscle, which is unlikely, because this muscle normally attaches to a smooth surface without marks or bumps on the underlying bone, and argued that the most likely explanation for the bumps was their initial interpretation as feather quill knobs. The authors admitted that it was unusual for quill knobs to form along the posterolateral surface of the bone, but also noted that the same arrangement is found in some modern birds, like the Moorhen."

What Arioch said is correct.  Mickey Mortimer and Andrea Cau, who are both palaeontologists that are among the best when it comes to theropods, both separately found the results of that examination to be flawed.  Here's a summary of this from the Concavenator Wikipedia page:

Some paleontologists have expressed not being convinced by the conclusions of Cuesta, Ortega and Sanz. Mickey Mortimer pointed out the ulnar bumps appear to actually be on the anterolateral surface of the bone, rather than the posterolateral as Cuesta et al. claimed, and that crocodilians are a better reference than birds for reconstructing the muscles of Concavenator and other non-maniraptoran theropods. Mortimer maintained the ulnar bumps are most likely part of an intermuscular line.[7][8] Andrea Cau compared the forearm of Concavenator to the articulated forearms of Allosaurus and Acrocanthosaurus and showed that this Concavenator specimen's forearm is dislocated and the ulnar bumps are on the anterior surface of the ulna and not the posterolateral surface. He pointed out this means that due to not being on the same part of the ulna, the ulnar bumps are not homologous to the quill knobs of paravians as claimed in both the original 2010 description of Concavenator and the 2015 results by Cuesta et al. Cau argued there are also other things that contradict the hypothesis that the ulnar bumps are quill knobs: the ulnar bumps of Concavenator are connected by a crest on the bone while paravian quill knobs are separate from each other, and the ulnar bumps of Concavenator are irregularly spaced while paravian quill knobs are uniformly spaced. Cau added that phylogenetics also make it unlikely an allosauroid like Concavenator would have quill knobs. He concluded that his interpretation was the ulnar bumps were part of the crest on the anterior side of the ulna perhaps for insertion of the musculature that connected the ulna and radius, pointing out that Balaur has a crest on the anterior side of its ulna which is homologous with that of Concavenator and has no relation with remiges.[9]

Furthermore, even if the ulnar bumps of Concavenator were quill knobs they don't provide any evidence that Concavenator was almost entirely scaly with only small areas of feathers/quills, which is what I said there is no evidence for in a theropod.  Concavenator could've been extensively covered in feathers, with quite long feathers on its arms instead of quite short quill-like structures, for example.

However, what I personally think is most likely for Concavenator's integument is either:
1. It was covered in simple filamentous feathers with no forelimb feathers/quills that were different from the body feathers.
or
2. It was covered in scales with no feathers/quills at all.

There is a lot against the idea that the ulnar bumps of Concavenator are quill knobs, and I agree with what Mickey Mortimer and Andrea Cau have said about this.  I'd recommend anyone who hasn't seen it yet, to take a look at Andrea's comparison of the arm of Concavenator to the arms of Allosaurus and Acrocanthosaurus.  I find it very clearly shows the Concavenator specimen's arm is dislocated and the ulnar bumps would actually be pointing in the direction of the radius.  The comparison can be seen here: http://theropoda.blogspot.co.uk/2016/03/le-papille-ulnari-di-concavenator-non.html

[Sim]

A doubt some of us had regarding the idea that the Tyrannosaurus skin patches show scales was that the skin detail didn't show very uniform scale patterns.

While looking at chameleons for the recent discussion in the Beasts of the Mesozoic thread, I noticed a couple of things about the scales on the white area on the top of the snout on this Parson's chameleon: https://goo.gl/images/McrTV9
The scales on that part of the snout have a lot of different shapes, and the scale shapes/arrangements are noticeably asymmetrical when comparing the left and right halves of the white area.

Some time ago, I also noticed this dodo foot shows a wide variety of scale shapes that don't form a pattern on some areas of the one foot: https://commons.wikimedia.org/wiki/File:London_Dodo_leg.jpg

So even if it's unusual, it does appear to be possible for some species to have areas where scales have a variety of shapes and aren't arranged in a pattern.  For comparison, the Tyrannosaurus skin can be seen in Mark Witton's blog post about this topic: http://markwitton-com.blogspot.co.uk/2017/06/revenge-of-scaly-tyrannosaurus.html

[Bowhead Whale]

All of this to say that we still don't know what was the exact texture of T-Rex's skin... Anyone can be right or wrong, in this case. In my opinion, T-Rex had very little feathers, like the hairs of an elephant or a rhinocéros. But who knows for sure?

[Tylosaurus]

TREY the Explainer made an awesome video on the subject:

https://www.youtube.com/watch?v=CxE68c9rYa0

This video explains everything you need to know, just accepts things as they are.

[Sim]

No, I watched that video when it first came out and it contains mistakes and is misleading.  The maker of the video acknowledged that video contains mistakes, here: https://twitter.com/markwitton/status/875653382421176320

[Neosodon]

No, I watched that video when it first came out and it contains mistakes and is misleading.  The maker of the video acknowledged that video contains mistakes, here: https://twitter.com/markwitton/status/875653382421176320

Yeah it bugged me that he made it sound like feathers on T. rex would not have had any effect on overheating especially since they would have been the filamentous kind. Trey likes to throw around words like evidence, reason and logic allot but he often does have biases, fails to acknowledge the other side and twists the evidence to support his own side.

[Loon]

Yeah it bugged me that he made it sound like feathers on T. rex would not have had any effect on overheating especially since they would have been the filamentous kind. Trey likes to throw around words like evidence, reason and logic allot but he often does have biases, fails to acknowledge the other side and twists the evidence to support his own side.

That was always my problem with Trey, I mean, I like him, he seems like a great guy, but he is very biased. His passion, though, is quite luring. His general feelings seem to me to be an extreme extension of "All Yesterdays"-style speculation. He shows genuine interest in these types of "liberal" reconstructions and often has presented them as informed hypothesis, rather than genuine speculation. The exposed dimetrodon spines idea he sparked interest in are a good example of this.

[stargatedalek]

Yeah it bugged me that he made it sound like feathers on T. rex would not have had any effect on overheating especially since they would have been the filamentous kind. Trey likes to throw around words like evidence, reason and logic allot but he often does have biases, fails to acknowledge the other side and twists the evidence to support his own side.

That was always my problem with Trey, I mean, I like him, he seems like a great guy, but he is very biased. His passion, though, is quite luring. His general feelings seem to me to be an extreme extension of "All Yesterdays"-style speculation. He shows genuine interest in these types of "liberal" reconstructions and often has presented them as informed hypothesis, rather than genuine speculation. The exposed dimetrodon spines idea he sparked interest in are a good example of this.

Exposed Dimetrodon spines is based on evidence that the spines were warped, bent, broken, and healed during life. No that doesn't mean they were exposed (plenty of fish damage their fin rays) but it definitely qualifies as a proper and informed hypothesis.

Sometimes he takes a concept to one logical extreme or the other, but it's still called a logical extreme for good reason.