The Palaeobiology Thread:

[Green Baron]

Hola,

Hate ? No.

IRL feathered dinosaurs are rare because feathers aren't preserved easily and 19th century preparation technique might have destroyed some traces, though i doubt it because in souther Germany they were able to prepare remains of food in the stomach as well as baby dinosaurs inside unlucky mother and Archaeopterix with full garment.

So "feathers for dinos" is mostly an assumption based on indirect evidence. Ornithischians and Theropods seem to have invented a feather-esque feature (not a modern, profiled flight device yet), but these are not exactly the majority of all dinos.

 

Edited October 2, 2017 by Green Baron

[Xemina]

Everyone, say your favourite dino! 

(Mine: Sinosauropteryx Prima)

[Green Baron]

Actually, those animals without a spine are far more interesting to a palaeontologist than any vertebrate. They are far more abundant and often used as specimen for relative chronology and in some cases indicators for environmental conditions. They were in fact so abundant that some of built really thick sediment layers, like 100s of meters. Jurassic is good example, as its three main phases are classified by spineless beings.

So, i once was radically questioned about the development of the Ammonites of the Swabian upper Jurassic. A classic subject. The tutor that took the exam was really sadistic and so i had to show up a second time, this time with the professor as the inspector and he was much more willing to let a student pass.

Long live the lobe !

 

Imagine scintillating colours, like the inner of a nice mussel:

https://en.wikipedia.org/wiki/Ammonoidea#/media/File:Haeckel_Ammonitida.jpg

Over the doorstep of the Universities museum hung (and probably still hangs) an humongous Ammonite of 1,5m diameter (or so ....).

:-)

Edited October 4, 2017 by Green Baron

[KerikBalm]

Feathers were basal to the T. rex clade. If T. Rex didn't have them, it would be a secondary loss of them. Skin impressions show that some areas of adult T.rex did not have feathers. One could say the same about various marine animals which still have small hairs in certain places (such as specialized whiskers), or hair that is too small to leave an impression. T. rex juveniles probably had a lot of feathers. Large adults would need them less, much like large mammals today don't have much hair (Elephants, Rhinos, for instance).

I'd guess that adult T.rex had some feathers, but not all over, and were not "fluffy".

[Green Baron]

 

If T. Rex didn't have them, it would be a secondary loss of them.

 

Not necessarily. Feather-like things where found in another sideline of the theropods, not at the Tyrannosauridae (i may have missed something). Keep in mind, we're looking at 100-200 millions of years and a broad range of specimen, ordered by certain bone indices that may or may not mirror kinship, as far as one can speak of kinship over these timescales and geographic spaces.

Many traits might have been lost, newly invented or activated over and over again. Flight was invented, animals went into the water (Ichtyosaurs) and out again.

All examples we have of T. rex have a skin with horn, like that of a turtle, there is no sign of feathers or like filaments.

[Scotius]

T. rex and most of his relatives lived in warm areas of Earth ( which covered bigger area than today, due to mild climate of Jurassic and Cretaceous). But dinosaurs lived also in polar areas of the globe, where night would last for up to  months and temperatures dropped significantly below zero. For populations living in such conditions feathers would be much more useful. Unfortunately our knowledge of dinosaurs living in harsh climates is very limited so far.

https://en.wikipedia.org/wiki/South_Polar_dinosaur

[mikegarrison]

On 10/4/2017 at 9:31 AM, Green Baron said:

Not necessarily. Feather-like things where found in another sideline of the theropods, not at the Tyrannosauridae (i may have missed something). Keep in mind, we're looking at 100-200 millions of years and a broad range of specimen, ordered by certain bone indices that may or may not mirror kinship, as far as one can speak of kinship over these timescales and geographic spaces.

Many traits might have been lost, newly invented or activated over and over again. Flight was invented, animals went into the water (Ichtyosaurs) and out again.

All examples we have of T. rex have a skin with horn, like that of a turtle, there is no sign of feathers or like filaments.

You can't lose feathers and then gain them back again. You could gain something back that was some kind of feather analogue, but to gain feathers back again would mean independently developing the exact same thing, which just doesn't happen.

[Green Baron]

8 hours ago, mikegarrison said:

You can't lose feathers and then gain them back again. You could gain something back that was some kind of feather analogue, but to gain feathers back again would mean independently developing the exact same thing, which just doesn't happen.

No, i cannot:-)

If is not as clear. A fully developed asymmetric flight ready device would be improbable but not impossible. And again, given the time scales animals could evolve from land adaption to fins and water life adaption. An index or toe can be gained and lost in 2 generations, a tail as well. The skin and its cover is highly variable, for obvious functional reasons as well as for example display. Losing and gaining happens every day.

Look at how feathers are assumed to have evolved from scales. I don't find reasonable links, i think a natural history museum might be a good place :-) Different forms of feather-like long hollow filaments (for convenience all called feathers ;-)) apparently have indeed developed several times out of a scaly skin in different, even distant branches of the lizard's world. The step from a scale to a feather sounds difficult, but if you take a closer look at how a scale can get long and hollow then it is not as improbable any more. Little birds are an example of how that might have looked like, they have both traits, scaly feet and filaments. A grown up bird has different forms of feathers, from huge flight feathers to fuzzy down. That's the highly improbable part, similarities show up in Archaeopterix, when the big lizards were mostly gone or about to take their leave.

But for the feather-feature in different branches of dinosaurs and ornithischians, really, no problem here ... :-) That is why some people think that all of the lizards might have had "feathers", which is (most probably) not the case, until today only relatively few have been described.

 

Edit: (i took out the Melanosome hint i wrote before but you can still use it for a search)

Very often and sadly in Wikipedia as well one reads of "reasons" for an evolutionary development meaning something serves for an outcome, has a purpose. This notion is misleading, to say the least, and gets us close to religion. Evolution has no "reason". A feather wasn't meant for flight in the first place.

Edited October 6, 2017 by Green Baron

[wumpus]

15 hours ago, mikegarrison said:

You can't lose feathers and then gain them back again. You could gain something back that was some kind of feather analogue, but to gain feathers back again would mean independently developing the exact same thing, which just doesn't happen.

I'd be surprised if this were really true.  I'd expect "lost" feathers to be part of the "dead code" of DNA, and thus make "neofeathers" based off of mutations of the old feather code to be wildly more likely than entirely new feathers.  There are likely a lot of ways to not express a gene, completely removing all traces of the DNA seems an unlikely one.

That said, it hardly means that such evolution  will actually happen regardless of the need for feathers and the existence of "feather DNA" in the genes.  As far as I know, a whale fetus has gills (as do other mammals), but such are lost by the time they are calves.  No evolution of whales have allowed them to retain gills.

[magnemoe]

24 minutes ago, wumpus said:

I'd be surprised if this were really true.  I'd expect "lost" feathers to be part of the "dead code" of DNA, and thus make "neofeathers" based off of mutations of the old feather code to be wildly more likely than entirely new feathers.  There are likely a lot of ways to not express a gene, completely removing all traces of the DNA seems an unlikely one.

That said, it hardly means that such evolution  will actually happen regardless of the need for feathers and the existence of "feather DNA" in the genes.  As far as I know, a whale fetus has gills (as do other mammals), but such are lost by the time they are calves.  No evolution of whales have allowed them to retain gills.

Feather might just be not enabled:
You don't have fur or an tail yet a few humans has been born with it, this is not because its reinvented just enabled. 
On the other hand none has been born with an trunk rater than an nose as its not in the primate dna.

[Green Baron]

I don't think @mikegarrison referred to inactive regions of the genetic code but rather to what is called convergence or analogy, the independent development of similar features. The feather feature in dinos might not be the outcome of a (for us today after a looong time visible or obvious) selective pressure as they aren't really suitable for flying and it has been speculated that they might not even be a cold adaptation of the skin. I read a paper about that cold adaption thing, i think it was in Science ?

So it would be improbable that independent lines developed "feathers" or better feather-like filaments.

But we don't know where the selection process went or if the feathers were just an "add-on", the outcome that some other adaptation brought with it. Why does the deer with the biggest antlers get the girls ? Because it signals "Hi lady, i am fit ! I can afford building up 15kg of bones and just throw them away afterwards !". Or what is it with a cocks ugly face colours and crests on head and throat and its feathers ? The ladies apparently like it, the best display wins. Sexual selection, doesn't serve for anything obvious if viewed from the future by a paleontolist.

Yeah, what did i want to say ? Ah, features that have a functional basis in an organism aren't good for classification, as they might have been developed independently because pressure. So setting all dinos with feathers in a relationship isn't a good idea. But then we have the case that feathers (or their versions 0.1) developed independently. And so it seems ...

Edited October 6, 2017 by Green Baron

[DAL59]

3 hours ago, sevenperforce said:

KABLOOIE!!!!!!!!!

Horrendous Space Kablooie

[cubinator]

11 minutes ago, DAL59 said:

Horrendous Space Kablooie

To be fair, Tyrannosaurus Rex is Latin for "Tyrant Lizard King", which seems like a pretty good descriptor.

However, spacecraft naming schemes do need to step it up a notch. "Space Launch System", for instance, describes literally every orbital and suborbital rocket ever. At least "BFR" gets the point across that it's a really big rocket.

[CatastrophicFailure]

17 minutes ago, cubinator said:

To be fair, Tyrannosaurus Rex is Latin for "Tyrant Lizard King", which seems like a pretty good descriptor.

Actually... 

...there’s a theory that T-Rex was primarily a scavenger, incapable of real hunting and mostly harmless... 

[DAL59]

1 hour ago, CatastrophicFailure said:

Actually... 

...there’s a theory that T-Rex was primarily a scavenger, incapable of real hunting and mostly harmless... 

[CatastrophicFailure]

11 minutes ago, DAL59 said:

I'm still out of likes, so here's a thesaurus. 

 

Getting back on track, so we know the beast can run for at least 6-8 seconds. Would that be enough to get it clear of the pad? 

[sevenperforce]

1 hour ago, CatastrophicFailure said:

Actually... 

...there’s a theory that T-Rex was primarily a scavenger, incapable of real hunting and mostly harmless... 

A theory which, I'm happy to say, has largely been deprecated. It was a terror indeed.

[tater]

T. rex. The specific name is never capitalized, only the generic name. Both are italicized. Behaviors of dinosaurs are... conjectural. That said, carnosaurs could all likely hunt, but nothing would prevent them from scavenging. Gotta love theropods.

 

[sevenperforce]

5 minutes ago, tater said:

T. rex. The specific name is never capitalized, only the generic name. Both are italicized. Behaviors of dinosaurs are... conjectural. That said, carnosaurs could all likely hunt, but nothing would prevent them from scavenging. Gotta love theropods.

 

Behaviors of dinosaurs are only conjectural insofar as we lack examples. Examples are not entirely lacking, however. We have fossilized prey dinosaurs with healed wounds made by T. rex, including one case where the tyrannosaur's tooth actually broke off and the prey healed premortem. T. rex certainly would have scavenged from time to time, but its reputation as a predator is by no means overstated.

It did have reptilian lips and feathers, though. Not too many feathers, probably just along its back, but still. Kinda weird.

[kerbiloid]

Spoiler

2 hours ago, cubinator said:

"Space Launch System"

Let NASA use the "space" key for ignition/staging like KSP does.

38 minutes ago, tater said:

T. rex. The specific name is never capitalized, only the generic name. Both are italicized.

Spoiler

I.rex.

Btw where are T.fido. and T.spot.?..

 

 

Edited January 25, 2018 by kerbiloid

[magnemoe]

2 hours ago, cubinator said:

To be fair, Tyrannosaurus Rex is Latin for "Tyrant Lizard King", which seems like a pretty good descriptor.

However, spacecraft naming schemes do need to step it up a notch. "Space Launch System", for instance, describes literally every orbital and suborbital rocket ever. At least "BFR" gets the point across that it's a really big rocket.

Its an name determined by an government comity, probably an large one using lots of time. 
Military also get them, "Standard missile" is an idiot name, think winner is "Gun system gun".
Just using an letter an number would be better. 

[Bill Phil]

3 hours ago, cubinator said:

To be fair, Tyrannosaurus Rex is Latin for "Tyrant Lizard King", which seems like a pretty good descriptor.

However, spacecraft naming schemes do need to step it up a notch. "Space Launch System", for instance, describes literally every orbital and suborbital rocket ever. At least "BFR" gets the point across that it's a really big rocket.

Well, there's also the Space Launcher System... it never flew, but as of now, neither has SLS. So there are two SLS rocket families...

[tater]

1 hour ago, sevenperforce said:

Behaviors of dinosaurs are only conjectural insofar as we lack examples. Examples are not entirely lacking, however. We have fossilized prey dinosaurs with healed wounds made by T. rex, including one case where the tyrannosaur's tooth actually broke off and the prey healed premortem. T. rex certainly would have scavenged from time to time, but its reputation as a predator is by no means overstated.

It did have reptilian lips and feathers, though. Not too many feathers, probably just along its back, but still. Kinda weird.

Taphonomy limits what we can know. A shed tooth tells little, unless it is embedded in a healed wound, for example, since even a scavenger would also shed teeth (theropods had deciduous teeth). A healed wound means it was bit while alive. Current ideas tend to lean heavily towards predation as their principal form of food gathering, however (which is where I stand on the issue). None the less, it's still conjectural since we have relatively small numbers of examples, and their relative abundance is entirely determined on the particular situation of the particular deaths that resulted in fossils being left. The bones scattered everywhere in East Africa will never be fossilized. Only  the few that happen to fall into the mud near a watering hole, for example will have a chance at mineralization. "Conjectural" is about as good as it gets for some things, there is nothing wrong with it, it's part of what makes paleontology interesting.

I should add that there was a Calvin and Hobbes where Calvin observes that the color scheme of the dinosaur he drew in school was "a bit conjectural." My comment was a sideways reference to that (I looked for a jpg of the comic online, and couldn't find it).

Edited January 25, 2018 by tater

[Hannu2]

9 hours ago, CatastrophicFailure said:

Actually... 

...there’s a theory that T-Rex was primarily a scavenger, incapable of real hunting and mostly harmless... 

If there were a (very fictional) situation in which crazy genetic scientists would have hatched some living T. rex individuals, would you like to test that theory in practice in tyrannosaur's cage? It would be nice win-win game. Lots of scientific merit if theory was right and certain Darwin award if it was falsified.

[sh1pman]

36 minutes ago, Hannu2 said:

If there were a (very fictional) situation in which crazy genetic scientists would have hatched some living T. rex individuals, would you like to test that theory in practice in tyrannosaur's cage? It would be nice win-win game. Lots of scientific merit if theory was right and certain Darwin award if it was falsified.

Being a genetic scientist myself (not yet crazy though), I suggest a better experiment: lock a group of... *volunteers* in a cage with T-Rex along with some carrion meat. Then observe and log its food preference, repeat at least three times with different T-Rexes for statistics.