Eofauna: New for 2022

[dinofelid]

I'll leave also an article from 2015 (before the discover of the microscales on the underbody of Tyrannosaurus) on his blog discussing feathering in general, on the left there is an automatic translator option (where it says: (TRANSLATE THIS BLOG) that works pretty well:

http://palaeos-blog.blogspot.com/2015/02/las-plumas-del-dinosaurio.html#


It's a very good reading with lots of pictures and facts.

He makes some good points but note that this blog entry is from before the paper Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution which tries to gather together all the cases of likely skin/integument impressions in different Tyrannosaurs, arguing for a consistent pattern of feathers being found on the smaller species but not the larger ones above a certain threshold. In the Palaeos video he does talk about the paper, my Spanish isn't good enough to fully understand it but it seems like he was dismissing some of the claims of the authors about which part of the body the skin impressions came from--unless significant doubts about where they came from were published in peer-reviewed papers, I'm always a little suspicious of online commenters who dismiss claims by scientists based on their own judgments rather than those of other scientists with different opinions. But since I'm not fluent in Spanish it's possible I misunderstood. In addition there are some arguments about integument no longer being useful for thermoregulation above a certain temperature-dependent size threshold, see for example this paper, it focuses on Triassic dinosaurs but the developers of the Saurian game have an article about the arguments for featherless Tyrannosaurs here where they mention that one of the paper's authors, Scott Hartman, was doing consulting work for them and seemed to think the arguments would apply to large Tyrannosaurs as well:

In addition to the physical evidence for reticulate scales, there is also a biomechanical argument to be made. One of our major consultants on this reconstruction, Scott Hartman, has been conducting physiological modelling on early dinosaurs and other reptiles, including quantifying thermal constraints (Hartman 2015, Hartman et al. 2016). He is not working specifically on T. rex, but his research has implications for its potential feathering. According to his research, depending on ambient temperature, animals stop receiving any benefit from dermal insulation at somewhere between 1 and 3 tonnes. Due to the costs of producing such integument, this may cause these traits to be selected against, as has occurred in many large mammals and fur.

Looking at the skin evidence from the rest of the dinosaur family tree, this shouldn't be that large of a surprise. If we assume that filaments are basal to all dinosaurs, then they have already been lost at least 4 times prior to tyrannosauroids: thyreophorans, cerapods, sauropods, and ceratosaurs. This makes feather loss in one additional clade hardly a stretch of the imagination.

[stargatedalek]

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.

A lot of people have suggested pretty serious issues with the 2017 integument paper. Most notably that the tiny size of the impressions in question, and the lack of evidence for their assigned location on the body, do not make for strong evidence for a broad claim against feathers as the paper asserts.

To say that critiques are only relevant when published is frankly rather disrespectful and misunderstands a lot of the environment paleontology currently finds itself in. A lot of good work gets done outside of published papers, especially with regards to life reconstructions. And just because someone doesn't have a degree doesn't mean they can't come to correct interpretations, and in some cases that can actually be an advantage.

Paleontology degrees do not as a matter of standard train paleontologists in life reconstruction. Nor do the geology, archaeology, biology and microbiology degrees that most universities make someone get first (to say nothing of the math, language, etc. degrees). Life reconstruction is something someone needs to train themselves in the vast majority of the time, and you're going to find that experienced paleoartists, amateur and professional both, are typically going to have a better application for comparative anatomy and a more up to date knowledge base of relevant information, relative to a degree holding paleontologist who unless they approach these fields of their own volition, has no expectation of experience in life reconstructions.



At the risk of sounding like David Peters "the establishment is dumb cause I figured something out first", I can't help but remember being a child, an actual child, in the 2000's when Microraptor was at the peak of its hype. There was a Nova special that featured BANDits, for some sad reason, and it felt like a new paper on Microraptor was coming out every couple of months. An awful lot of them were wind tunnel studies, and no matter what new idea they had for leg poses or configurations, they could never get Microraptor to make sense as a gliding animal.

Right from the start, the papers were saying, frankly ad nausea with how many people did these same tests, that Microraptor was completely incapable of gliding to a relevant efficiency, and that it would only have gained lift while moving at speed, and yet all promoted the same conclusion that Microraptor was a gliding animal. As a small child of maybe 8 or 9, it was painfully, flagrantly, enragingly obvious that Microraptor flew. As someone who knew none of the physics or the terms regarding parts of the skeleton or aerodynamics, just from a vague ability to understand the context of the statements and data included and from reading the papers own conclusions/summaries, that much was clear.

And yet dozens of degree holding scientists ignored their own results for almost 15 years. I am by no means abnormally smart nor frankly do I believe I was a particularly smart child, anyone reading that data should have been able to come to the same conclusion, but they refused to see it. I'd pointed this out to people numerous times, always to be meet with "It didn't fly because it wasn't a bird". No reasoning, no explanation, just "because the culture in the field says no that means no". So I am of the mindset that oftentimes with life reconstruction outside opinions can hold considerable merit.

It would take a study on molting patterns of all things before the establishment finally acknowledged that Microraptor flew.

[Willaim bratton]

Full body feathering is out , but scattered feathering in between scales, or feathering restricted to the dorsum are possible ( see PR.Bell.2017) as seen in Collecta 2018 and yes, Eofauna's most recent art. Infact we also have the what looks like plucked bird skin from Tyrannosaurus

[GiganotosaurusFan]

Eofauna's T. Rex doesn't seem promising in my honest opinion, but I could be wrong. I prefer Rebor's Kiss.

[dinofelid]

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.

Is there any specific fossil evidence of feathers in Deinocheirus? People on this thread say feathers are just inferred based on phylogenetic bracketing, and someone also links to this post from Mark Witton (who is both a paleontologist and a paleoartist) which talks about his research into the thermoregulation argument for loss of integument, and includes his own depiction of a mostly "naked" Deinocheirus with the comment "After researching this article, images like this read as more plausible to me than the general 'walking haystack' guise Deinocheirus has attained in palaeoart."

A lot of people have suggested pretty serious issues with the 2017 integument paper. Most notably that the tiny size of the impressions in question, and the lack of evidence for their assigned location on the body, do not make for strong evidence for a broad claim against feathers as the paper asserts.

To say that critiques are only relevant when published is frankly rather disrespectful and misunderstands a lot of the environment paleontology currently finds itself in. A lot of good work gets done outside of published papers, especially with regards to life reconstructions. And just because someone doesn't have a degree doesn't mean they can't come to correct interpretations, and in some cases that can actually be an advantage.

It's true that I did make reference to "peer-reviewed papers" but I didn't mean to suggest that even people with the relevant scientific training shouldn't be taken seriously when they challenge published papers outside of academic journals, my suspicion was reserved for people who don't have the same level of expertise as the scientists in the field (like your example of David Peters) who challenge papers based exclusively on their "own judgments rather than those of other scientists with different opinions". If there are other scientists who challenged the claims about the location of the skin impressions on the body, even if they didn't do so in published papers, can you point to one or more examples?

Paleontology degrees do not as a matter of standard train paleontologists in life reconstruction.

I can see how knowledge of specific issues related to life reconstruction might matter more when it comes to things like interpreting whether a featherless skin impression actually implies the skin was likely bare in life or if it's equally likely that feathers were lost from the body after death but before the skin decayed. But the specific thing in the video that I was pointing to was the suggestion that the scientists who wrote the paper were completely wrong in their claim about where on the body some of the impressions actually came from. The paper doesn't say how they determined this, but I would think there'd have been some basis for this claim in terms of where the impression was found in the excavation site, and that in general assigning body locations to different parts of a fossil find is something that paleontologists are well trained in.

[edu]

Eofauna's T. Rex doesn't seem promising in my honest opinion, but I could be wrong. I prefer Rebor's Kiss.

Well, we'll have to wait, it's too early! We have two tyrannosaurs "from them". One is lipless, on the skinny side and unfeathered. The other has some feather, lips and is really bulky. If they are working on the design now, they will have to look at all the evidence and make their decisions, i don't think those depictions, being so different, are really telling what we are getting.

[Psittacoraptor]

@stargatedalek is right about paleontology as a field. Some people have a distorted view of what academic paleontology is. Just because something is published in a journal doesn't mean it's beyond criticism. And many good ideas are not published. Vertebrate paleontology and life reconstruction is a small, underfunded area of an already small field. Paleontology is, for the most part, an "aid science" for other earth science fields, such as paleoclimatology, stratigraphy, sedimentology, prospecting etc.. You'll have a hard time finding employment if you specialize in reconstructing dinosaurs. Money and work are found elsewhere, e.g. in micropaleontology or paleopalynology. Want to make a living in paleontology? You'll have much better chances if you specialize in studying the properties of fossilized foraminifera or dinoflagellates as proxy data for paleoclimates, as opposed to reconstructing dinosaurs.

[SRF]

Eofauna's T. Rex doesn't seem promising in my honest opinion, but I could be wrong. I prefer Rebor's Kiss.

Well, we'll have to wait, it's too early! We have two tyrannosaurs "from them". One is lipless, on the skinny side and unfeathered. The other has some feather, lips and is really bulky. If they are working on the design now, they will have to look at all the evidence and make their decisions, i don't think those depictions, being so different, are really telling what we are getting.

The skinnier one that I posted from the book isn't featherless actually. Is has a very thin coat of small feathers on top of its head and neck. It's more visible on the picture in the book itself.

[Leyster]

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.

Is there any specific fossil evidence of feathers in Deinocheirus? People on this thread say feathers are just inferred based on phylogenetic bracketing, and someone also links to this post from Mark Witton (who is both a paleontologist and a paleoartist) which talks about his research into the thermoregulation argument for loss of integument, and includes his own depiction of a mostly "naked" Deinocheirus with the comment "After researching this article, images like this read as more plausible to me than the general 'walking haystack' guise Deinocheirus has attained in palaeoart."

Recently, Witton's argument about terrestrial sloths has been challenged. No furless Megatherium, it looks like. Without the sloth thing, the whole argument more or less falters. Also I don't know if Witton kept in account that feathers, even simple ones, are different from fur: here is a research made on emu and kangaroo pelts (their different body masses are not a factor, then) and it shows that, despite being darker, the feathering protects the emu better from heat and that it's relatively heavy coat almost prevents the heat from reaching the skin, thus mantaining the animal cool.

[Duna]

He makes some good points but note that this blog entry is from before the paper Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution which tries to gather together all the cases of likely skin/integument impressions in different Tyrannosaurs,

Yes, yes, that's true, that article is before the findings of Tyrannosaurus skin, but he talks about that in the video I posted in the other post. In the video he talks about most of the facts discussed in the blog, but also adds about the "scaly" skin discoveries.

Is there any specific fossil evidence of feathers in Deinocheirus?

Yes, there is. This is part of its fossil pygostyle. Lee et al (2014). The pic appears in Paleos article in the blog. So not exactly like there are "feathers" fossilized but its evidence. As in Deinonychus. No fossil of deinonychus feathers has been found and however no one today would think it wasn't, same as 99% of mammal fossils without fur (out of permafrost).
And I highly suggest you watch Paleos video (in translation mode) about the T-rex discuss because he explains everything about feathers. And yes, feathers are one of the best insulating devices in the animal world, perfect for both very cold and very hot climates.

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.
A lot of people have suggested pretty serious issues with the 2017 integument paper. Most notably that the tiny size of the impressions in question, and the lack of evidence for their assigned location on the body, do not make for strong evidence for a broad claim against feathers as the paper asserts

Yes, oh, those things are discussed in an absolutely brilliant way in Paleos video. The part in which he reviews the size and position of that integument it's superb. I highly suggest you all watch that part.

[GojiraGuy1954]

Echoes of back when the EoFauna trike was started to be teased lol

[Dinoguy2]

He makes some good points but note that this blog entry is from before the paper Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution which tries to gather together all the cases of likely skin/integument impressions in different Tyrannosaurs,

Yes, yes, that's true, that article is before the findings of Tyrannosaurus skin, but he talks about that in the video I posted in the other post. In the video he talks about most of the facts discussed in the blog, but also adds about the "scaly" skin discoveries.

Is there any specific fossil evidence of feathers in Deinocheirus?

Yes, there is. This is part of its fossil pygostyle. Lee et al (2014). The pic appears in Paleos article in the blog. So not exactly like there are "feathers" fossilized but its evidence. As in Deinonychus. No fossil of deinonychus feathers has been found and however no one today would think it wasn't, same as 99% of mammal fossils without fur (out of permafrost).
And I highly suggest you watch Paleos video (in translation mode) about the T-rex discuss because he explains everything about feathers. And yes, feathers are one of the best insulating devices in the animal world, perfect for both very cold and very hot climates.

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.
A lot of people have suggested pretty serious issues with the 2017 integument paper. Most notably that the tiny size of the impressions in question, and the lack of evidence for their assigned location on the body, do not make for strong evidence for a broad claim against feathers as the paper asserts

Yes, oh, those things are discussed in an absolutely brilliant way in Paleos video. The part in which he reviews the size and position of that integument it's superb. I highly suggest you all watch that part.

I would seriously question the "pygostyle" of Deinocheirus as evidence of feathers. Short rod shaped pygostyles are known in a variety of taxa and are not necessarily associated with feather attachment. They are more associated with tail shortening. Even in prehistoric birds, with feathers preserved, this type of pygostyle is just the shortened remains of a tail and does not play any special role in the attachment of feathers like true pygostyles do. I've seen several prominent early bird researchers suggest these structures should not even be called pygostyles at all to avoid confusion.

[Dinoguy2]

The argument against feathers on basis of size ignores other large theropods, such as Deinocheirus, that show evidence of feathers above the alleged weight based cut off point.

Is there any specific fossil evidence of feathers in Deinocheirus? People on this thread say feathers are just inferred based on phylogenetic bracketing, and someone also links to this post from Mark Witton (who is both a paleontologist and a paleoartist) which talks about his research into the thermoregulation argument for loss of integument, and includes his own depiction of a mostly "naked" Deinocheirus with the comment "After researching this article, images like this read as more plausible to me than the general 'walking haystack' guise Deinocheirus has attained in palaeoart."

Recently, Witton's argument about terrestrial sloths has been challenged. No furless Megatherium, it looks like. Without the sloth thing, the whole argument more or less falters. Also I don't know if Witton kept in account that feathers, even simple ones, are different from fur: here is a research made on emu and kangaroo pelts (their different body masses are not a factor, then) and it shows that, despite being darker, the feathering protects the emu better from heat and that it's relatively heavy coat almost prevents the heat from reaching the skin, thus mantaining the animal cool.

If I'm reading this thread right, the author found Megatherium would optimally have fur between 10-50mm in length? Not exactly the shaggy traditional appearance if so. On an animal that size it's the equivalent of peach fuzz.

[Duna]

I would seriously question the "pygostyle" of Deinocheirus as evidence of feathers. Short rod shaped pygostyles are known in a variety of taxa and are not necessarily associated with feather attachment. They are more associated with tail shortening. Even in prehistoric birds, with feathers preserved, this type of pygostyle is just the shortened remains of a tail and does not play any special role in the attachment of feathers like true pygostyles do. I've seen several prominent early bird researchers suggest these structures should not even be called pygostyles at all to avoid confusion.

He explains that in his article about the "change in look in Deinocheirus".

The thing is that it is not actually a pygostyle like that of birds, but rather it is more similar to that of oviraptors and therizinosaurs... That is why another name is being considered, since this structure is not homologous in birds and deinocheirus.

So if that "pygostyle" is similar to that of oviraptors and therizinosaurus and no one doubts they were feathered ... for me, it's just perfectly plausible. More than it wasn't unfeathered.

[Concavenator]

https://www.youtube.com/watch?v=1IkaEIUhlQk

Thank you for posting that video, @Duna . I'd seen it before and I also recommend it to anyone interested in knowing more about tyrannosaurid integument. That channel is pretty good.

@stargatedalek is right about paleontology as a field. Just because something is published in a journal doesn't mean it's beyond criticism.

Good point. In science, if we'd taken everything appearing on a paper as the absolute truth, we wouldn't have nearly as much knowledge as we currently have. Bell's et al. 2017 paper has some issues, some of which are even acknowledged by the very authors. If anyone wants to know more, go watch that video Duna posted. It is looking like, ever since that 2017 paper was published, even the slightest feathering on an tyrannosaurid was simply going to be called "outdated", as an immediate way of rejecting and avoiding previous completely feathered interpretations à la Yutyrannus, which started to seem unlikely. But the presence of feathers and scales isn't mutually exclusive, extant birds have scales on their feet, for instance. Juravenator is another example, this time, in a non-avian theropod.

[Leyster]

If I'm reading this thread right, the author found Megatherium would optimally have fur between 10-50mm in length? Not exactly the shaggy traditional appearance if so. On an animal that size it's the equivalent of peach fuzz.

Well, not exactly. The author describes it as

a fair amount of fur coverage

and that

while the sparse fur curves did not intersect with the predicted metabolic ranges

and so

Megatherium on the other hand would have had a physiological need for fur coverage to endure colder Southern temperatures in Argentina and Chile.

. So it would't be shaggy, but neither naked. Something like that in Deinocheirus will look more or less like how Atuchin restored it in the Eofauna book:

But that's a rough comparison. If you check the study I linked, you'll find that fur and feathers (even simple ones) are quite different in their heat retaining properties.

[stargatedalek]

Pygostyle as seen in Deinocheirus and Oviraptorosaurs were not for feather attachment, but are designed to facilitate a vertical twitching movement. The only purpose to these would be for finer control of display structures on their tails, which would be feathers.

[Concavenator]

I said this back when the Diplodocus was first teased last year, but I'll say it again. I'm happy that @Eofauna have shared which species they're working on for their next figure, instead of having us completely in the dark until they fully reveal it. A sense of expectation is much better than a sense of uncertainty. Not only that, but it also makes it possible sending feedback to them before it's all settled.

As a side note, I hope Andrey Atuchin will choose the colours for the Tyrannosaurus, as he did with the Dippy. I think that would be a good decision, imo the Diplodocus has the most impressive colour scheme of any Eofauna model so far.

[dinofelid]

Pygostyle as seen in Deinocheirus and Oviraptorosaurs were not for feather attachment, but are designed to facilitate a vertical twitching movement. The only purpose to these would be for finer control of display structures on their tails, which would be feathers.

Mark Witton did include longer tail feathers in his painting of the mostly-naked Deinocheirus. I think even if one finds the arguments about thermoregulation convincing, it would also be plausible to give it long arm feathers as well, since those are known to have existed in plenty of flightless dinosaurs including Ornithomimus, presumably used for some other function like display or keeping eggs warm. Neither would conflict with the argument for loss of feathers on most of the body due to the danger of overheating in large animals, any more than the tuft of long hair on an elephant's tail conflicts with it.

I also wonder if there's any strong reason to rule out the possibility that smaller ornithomimosaurs had fans of tail feathers, but that Deinocheirus had lost these feathers and the pygostyle was just vestigial. Did the pygostyle have significantly more bone mass than unfused tail vertebrae would have, so that having one would have some significant selective "cost" in an animal that lost its tail feathers? The photo in extended data figure 3 from this paper shows it was small compared to cervical vertebrae, though doesn't show its size in comparison with unfused caudal vertebrae from the tail. (Fig. 1 from that paper shows full-body skeletal reconstructions of two Deinocheirus specimens but for some reason it looks like the pygostyle isn't included in the reconstruction marked "a" of specimen MPC-D 100/127, which figure 3 says is the one that had it.) And even if there would have been some slight selective disadvantage to retaining a small pygostyle when it was no longer needed to support feathers, the loss of vestigial features can be a slow process, as with the diminishment of hind legs and hip bones in early whales. Though even if there's no good reason to rule out this idea, I also don't imagine there'd be any good reason to favor it over the idea that Deinocheirus did have long feathers on the end of its tail.

BTW, fig. 4 of that paper includes a life restoration, also shown in this blog entry, they also chose to depict it as mostly naked but with remaining long feathers on the arms and the end of the tail, along with some on the head.

[dinofelid]

Recently, Witton's argument about terrestrial sloths has been challenged. No furless Megatherium, it looks like. Without the sloth thing, the whole argument more or less falters.

As noted by D @Dinoguy2 , this tweet from that linked thread says that they speculate Megatherium most likely would have fur of length "50 mm in cold temperatures and 10 mm in warmer temperatures." So I don't think that really qualifies as a challenge to Witton's actual argument about Megatherium, it just shows that his speculative painting of an elephant-like naked Megatherium goes a little too far. But in the text of the piece he makes clear he's just arguing against traditional "shaggy" depictions of Megatherium fur, which I think would be intended to refer to fur a lot longer than 1-5 cm. He starts off by saying:

Rendering giant prehistoric animals with extensive hairy coats or thick feathery coverings is a convention now so well established within palaeoart that few of us give it a second thought. While this practise is well-grounded in fact for some cold-adapted Pleistocene megamammals, such as woolly mammoths and woolly rhinoceros, our treatment of other giant species - giant sloths and giant coelurosaurs - has a greater basis in tradition and expectation than fossil data.

Then a little later says:

Megasloths are, near-universally, restored with the same shaggy fuzz first given to them by Benjamin Waterhouse Hawkins in 1854 and it now seems shocking and wrong to see one without that characteristic pelt

You can see one of Hawkins' illustrations here, the fur is shown as long and matted.

Later when talking in more detail about thermal energetics, he says that "a hairless 4-tonne sloth with a typical placental metabolism would be thermally neutral at -17°C" and that in this case "we have to wonder if the shaggy pelt traditionally applied to Megatherium would be cooking an already very warm animal". Then he references another paper that calculated that if Megatherium had a slower metabolism, about half that of typical placental mammals, this assumption "leads to thermoneutrality at 10°C, a figure comparable to animals that inhabit temperate settings today without the need for long, shaggy fur." So you can see that he always makes a point of repeating this adjective "shaggy" in discussing the type of reconstruction he's arguing against, and presumably when he said "comparable to animals that inhabit temperate settings today" he was taking about mammals that do have short fur.

Also I don't know if Witton kept in account that feathers, even simple ones, are different from fur: here is a research made on emu and kangaroo pelts (their different body masses are not a factor, then) and it shows that, despite being darker, the feathering protects the emu better from heat and that it's relatively heavy coat almost prevents the heat from reaching the skin, thus mantaining the animal cool.

Is it possible this effect would be specific to pennaceous feathers though, not to more primitive "dinofuzz"? If that is possible, is there reason to think ornithomimosaurs (or tyrannosaurs) had evolved the former rather than the latter?