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LordofGorillaCheeks In reply to LordofGorillaCheeks [2015-05-24 00:50:05 +0000 UTC]

I contacted Joschua Knuppe and he said that the square cube law isn't a strong (let alone important) factor when it comes to integument. That also suprised me. I guess you learn something new everyday. I also contacted Mark Witton but he's busy so he hasn't contacted me back yet. Just letting you know. Have a nice day .

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LordofGorillaCheeks In reply to LordofGorillaCheeks [2015-05-22 22:59:54 +0000 UTC]

I'm not good with math so I can't really elaborate on the square cube law more in-depth, but many modern paleonotologists (people who are MUCH smarter than myself) reconstruct their larger bodied theropods with a fair amount of feathers, tropical or not. I suggest contacting Mark Witton, Brian Engh, Scott Hartman, Jaime Headdon, Joschua Knuppe (commonly known as Hyrotrioskjan) and possibly the creators of the Saurian game (seeing as how the latter are suprisingly well versed in the art of paleontology). I will be doing this myself, although I'm basically just going to ask all of them since I know from first hand experience that most of them are busy 24/7, so I know that it might take a while for a response. Like I said with how terrible things are preserved, stating that because an animal has large scales doesn't mean that it doesn't have any form of integument. Feathers could easily grow between the scales or could originate on the top of the ridge of the back, and then become long enough to effectively cover certain areas of the body. Like you said yourself, the scales of some dinosaurs (including more advanced Tyrannosaurids) show the same type of scales that are found on some feathered avian dinosaurs.
nd01.jxs.cz/022/071/9917579527…
Also, emus and cassowaries aren't that much bigger from one another. Both animals are about the same size and come from an envirenment that's very similiar (although the Cassowary is usually found in more shaded areas, yet still has SLIGHTLY more feathers). Yes, the square cube law has an effect in this equation, but it's not a uniform math equation. Living organisms aren't just numbers on a graph, they are incredibly strange and easily evolove or retain things from there ancestors without having to follow some mathematical equation (well... not completely). Also, look at the elephant bird. It is about the weight of he average black rhinoceros and is much larger than the modern day ostrich, yet still has more feathers than it. If the square cube law was as uniform as you make it sound, then this animal would have much less integument, and would look rather bald. It even has more feathers than the much smaller emu. This animal was also found in an envirenment in Madagascar that resmbles the arid scrubland of Southern and Eastern Africa (places where ostriches are commonly found). This animal had more feathers than the square-cube law implies since it's not just some number on a graph. It's an animal. A strange one at that but still an animal. Like I said, I recommend that you do like me and ask the people I mentioned above.

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amorousdino In reply to LordofGorillaCheeks [2015-05-22 08:52:48 +0000 UTC]

As much as I like Saurian's Tyrannosaurus design (and all their dinosaur designs in general), we do have some skin impressions of large bodied tyrannosaurids that show scales and glabrous skin, no feathers as of yet. Though the feather impressions of large bodied tyrannosauroid Yutyrannus show that that even they could have feathers, Yutyrannus is thought to have lived in a fairly cool environment, unlike the generally warmer habitats of the later tyrannosaurids that have left skin impressions. So it's safer to depict large tyrannosaurids with less feathers until further evidence proves otherwise. I generally stick with giving them small patches of primitive feathers either for display or just vestigial bits of integument.  

 largestcoelurosaur.tumblr.com/…

The issue with thermoregulation with large animals is that with an increase in overall mass, they don't need a great deal of feathery or furry integument, their large mass alone is enough to accumulate and maintain heat. Given that a lot of these tyrannosaurs lived in warmer climates, they would not have needed a lot of feathers to keep warm. In fact, large amounts of feathers would have been counterproductive as they would overheat constantly. This is one of the reasons why you don't see the megafauna on the African plains like elephants, rhinos and hippos with that much fur. They'd just overheat all the time. Their mass alone is good enough. 

Woolly mammoths and rhinos show that in colder climates mainlining warmth from mass alone is not enough, so furry integument is necessary. Tyrannosaurs in colder climates probably were feathered, maybe even to the point of being woolly. 

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LordofGorillaCheeks In reply to amorousdino [2015-05-22 13:04:29 +0000 UTC]

Yes that's very true when it comes to hairs, but feathers are rather more "advanced" in that they are both beneficial for heating and cooling. This is in part to the branch like endings found along the sides of the feather, which can better keep in or release heat. The square cube law does go hand in hand with this just like hairs, but the presence of feathers would be much more common in a larger bodied animal than a larger bodied "furry" animal due to a drastict decrease in the chance of overheatting. Also, an animal regardless of it's size can easily benefit by having a heating AND cooling system. That's why an ostrich has much more integument than an equally sized ungulate mammal that also lives in the same envirenment. When it comes to the preservation of soft tissues, the fossilization process is a rather... how you say... "cheeky bastard" to say the least. Fossilization in general is highly inconsistent when preserving anything, and soft tissues are a good example. One example would be how most mummified wooly mammoth remains are baren of hair, with some individuals having random patches of hair only on certain parts of the body (which is also prevelant in several feathered non-avian dinosaur remains). I can only think of one individual that has an "ordinary" coat of fur (and even then the animal itself barely looks like a mammoth). This is an animal we're talking about here that has just recently died a few thousand years ago (which is a metaphorical blink of an eye compared to the last non-avian dinosaur), has a body completley covered in integument (so the chances of hair preservation are much higher) and died in an almost perfect place for soft-tissue preservation. All of that and yet it stills barely looks like a mammoth, let alone an animal that has large amounts of hair. Other naturally mummified remains also show this pattern (which I've seen several times first hand at my museum). Animals (including people) that have been preserved for the past few thousand to few hundred years, yet have very little to no integument (or muscles for that matter) at all. Other examples I can give are things like wooly rhinoceros, wild oxen, cats, dogs, humans, lizards (nothing to do with integument but just to do with actual preservation) and of course, birds. It also seems as though that feathers in general are harder to preserve than many forms of hair (due to being lighter and more fragile), and this is no exeption in the fossil record. There are partially preserved remains of many extinxct birds (including Archaeopteryx) that sometimes show all (or most) of the feathers, some that just show the arm and/or tail feathers, and some that don't show any feathers (but still partially preserve the leg scales).
nuxx.net/gallery/d/96984-1/P42…
s-media-cache-ak0.pinimg.com/2…
These are racoons. Dead racoons that have been eroded away by the sun, bacteria and water (especially the latter which was dragged out to sea, and also stirred up the controversy of the government experimenting on animals). What if one of them (especially the latter) were to be buried by river sediments after eroding in the sun for several days to weeks? It wouldn't look like a racoon now would it? It would look like some bald, hollywood movie monster. See what I'm getting at? Overall, the feathers were prevelent in this animal, it's just that it didnt preserve due to how terrible the fossilization process is. Things like Dilong and Yutyrannus are the exception because they arguably come from the most rich, fertile formation from the Mesozoic era.

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amorousdino In reply to LordofGorillaCheeks [2015-05-22 20:41:22 +0000 UTC]

As I mentioned before, mass alone would be enough for heat conservation and any thick integument would be a hindrance in the cooling process, as efficient as feathers are in cooling.

We've seen that filamentous structures are common in most dinosaur families, from the megalosaurs (Sciurumimus) to the various Ornithischian families (Psittacosaurus, Kulindadromeus) but when we get to larger members of these groups, that get above rhino size, we see less and less filamentous structures. Take the albelisaurid Carnotaurus, large hadrosaurs like Edmontosaurus, ceratopsians like Triceratops, we have good skin impressions of these and they show scales and little to no filamentous structures. There is a rumored specimen of Triceratops with what look like quills but they were said to be sparse upon the scaled body. It seems a number of these animals evolved to be scaly secondarily, having lost their ancestral integument as they got bigger in warm environments. 

Same can be said with tyrannosaurs, as we have primitive members like Dilong that have feathers but as we progress to the larger tyrannosaurs found in warmer regions, we find scale impressions, while Dilong's contemporary Yutyrannus spots a shaggy coat because it needs to keep warm in a cool environment. These large bodied tyrannosaur skin impressions are not very extensive (Tyrannosaurus, Tarbosaurus) but what little we do have indicate scales. But the Tarbosaurus and Gorgosaurus skin impressions also show glabrous skin. As you said with feathers and fur being difficult to preserve, these bits of glabrous skin could have held feathers. As of now, feathering a large bodied tyrannosaur in a warm environment is primarily speculative. 

The problem with using modern ratites as an analogy for very large bodied theropods is that they've never gotten past rhino-size. They don't have to deal with the increased mass that these very large theropods have had. Even with their current size, larger ratites in warmer climates do show some decrease in overall feather coverage in their bodies as they get bigger, compared to smaller ratites. Their heads are sparsely covered in very fine filaments and their lower legs show a decrease in feathers as well with an increase in size. The bigger they get, the more extreme this gets. Cassowaries are quite shaggy all around (with the exception of their heads), but emus are less so in their lower limbs, while ostriches lack almost any heavy feathering on their lower legs. Now compare this to the smallest of ratites, the kiwi. 
www.australianbushbirds.info/g…
upload.wikimedia.org/wikipedia…
4.bp.blogspot.com/-Jjtr67AkK_w…
www.yurtopic.com/travel/destin…

I do feather my large tyrannosaurs, but to the same extant that large ratites have fine but sparse feathers on their heads, some vestigial integument from their ancestors, and more extensive bits of feathers for display purposes. While I give my smaller tyrannosaurs more extensive feather coverage for thermoregulation. 

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MugenSeiRyuu In reply to TinkerTanker44432 [2017-07-03 20:14:53 +0000 UTC]

None of them is a  T.rex. Both are Albertosaurus sarcophagus.

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amorousdino In reply to FiliusTonitrui [2015-11-28 02:04:37 +0000 UTC]

Yup. 

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FiliusTonitrui In reply to amorousdino [2016-03-16 03:43:20 +0000 UTC]

Never mind. I thought those were supposed to be T. rexes, but albertosaurus had smaller teeth.

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FiliusTonitrui In reply to amorousdino [2015-11-28 12:22:25 +0000 UTC]

Why?

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