Re: Feathering proof

[Balaur]

Crocodiles had reasons for loosing them, dinosaurs did not. Archosaurs, but especially birds, are very dependent on visual communication, to which feathers are excellent. The concept of sauropods retaining feathers, but using them for display and nothing else seems fully reasonable to me.

Again, as I was saying the feathered ancestor of both dinosaurs and pterosaurs was likely a primitive ornithodire, a group that excludes crocodiliformes. Therefore crocodilians would never have had any feathers to lose.

But, what about the dromant genes for feather production in crocodiles? I'm not saying that crocodiles did have feathers.

[Yutyrannus]

Crocodiles had reasons for loosing them, dinosaurs did not. Archosaurs, but especially birds, are very dependent on visual communication, to which feathers are excellent. The concept of sauropods retaining feathers, but using them for display and nothing else seems fully reasonable to me.

Again, as I was saying the feathered ancestor of both dinosaurs and pterosaurs was likely a primitive ornithodire, a group that excludes crocodiliformes. Therefore crocodilians would never have had any feathers to lose.

But, what about the dromant genes for feather production in crocodiles? I'm not saying that crocodiles did have feathers.

So then there are feather production genes in crocodiles, then?

[Balaur]

Oh. I just realized you were not talking about that. My bad!

[Yutyrannus]

Oh, okay.

[stargatedalek]

modern crocodiles possess feather producing genes, meaning their ancestors had feathers (or feather like integument) at some point
they lost them most likely because they became aquatic, which is how elephants lost (most of) their hair

[tyrantqueen]

I have a question. In the past dinosaur eggs have been found and some of them have been known to contain embryos inside. When the preservation was good enough, there were even examples of babies found with skin patches (see below):
http://news.bbc.co.uk/1/hi/sci/tech/216105.stm

If this baby sauropod had feathers or fuzz like some individuals like to think, would it not have exhibited them in this fossil evidence? If it has grown skin at this stage, why hasn't the fuzz/feathers preserved too? Baby birds grow their feathers when they're inside the egg:



Your thoughts.

[Balaur]

Actually, some birds are born altricial, and sometimes are naked, and don't have feathers until later.

[tyrantqueen]

Actually, some birds are born altricial, and sometimes are naked, and don't have feathers until later.

What about precocious ones? If I remember correctly precociality is ancestral to avians (and some dinosaurs such as Troodon). I don't believe that sauropods would have exhibited (or been capable of exihibiting) much parental care.

[Balaur]

Actually, some birds are born altricial, and sometimes are naked, and don't have feathers until later.

What about precocious ones? If I remember correctly precociality is ancestral to avians (and some dinosaurs such as Troodon). I don't believe that sauropods would have exhibited (or been capable of exihibiting) much parental care.

Yes, sauropods were probably precocial, or even superprecocial, just pointed that out. There may be a sauropod out there that exhibited some (if even weak) form of parental care.

[Trisdino]

For the "would feathers in babies have been preserved", short answer, no, long answer, yes but the chances of it happening are very slim.


Feathers always have a hard time preserving, they must be in exactly the right place at the right time. We have found oviraptor eggs with chicks inside, but they show no feathers, though we know they probably had them(though the could have grown them later)

[tyrantqueen]

For the "would feathers in babies have been preserved", short answer, no, long answer, yes but the chances of it happening are very slim.


Feathers always have a hard time preserving, they must be in exactly the right place at the right time. We have found oviraptor eggs with chicks inside, but they show no feathers, though we know they probably had them(though the could have grown them later)

I know that skin and feathers don't always preserve. But I was specifically asking about instances where they do. I am not saying that oviraptor did not have feathers because they weren't found with any. From what I understand, the oviraptor eggs just had a jumbled mess of bones inside.

[Trisdino]

Yes, they did, the oviraptor skeleton was not very well preserved, nor were the eggs.


Basically, for feathers to preserve, the animals, or in this case, eggs, would have had to have died in something that preserves soft tissue, like say, a swamp, or a flash flood covering it in mud. Then the fossil would have had to never emerge, as would probably ruin the feather impressions, and stay underground in calm conditions since the day it died.

[stargatedalek]

not to mention the egg itself would have to permeated quickly, even if the sediment sealed the egg than the embryo inside could still rot and degrade

[amargasaurus cazaui]

A large number of eggs found unhatched did suffer rapid flooding or complete burial in mud moist enough to suffocate the animal inside, and most often quite rapidly. Oviraptor eggs seemed to suffer this fate often, however an egg is made to breathe both water and air through the shell and the animals would often decompose regardless if it was buried or flooded.

[Dinoguy2]

One thing to keep in mind is the significant difference between feather stains and feather impressions.

Most Archaeopteryx specimens don't preserve feathers stains, but they preserve the impressions (either casts or molds) of feathers.

Most Liaoning fossils do not preserve impressions of anything at all. Not of scales, skin, or feathers. What they preserve are organic carbonized stains of the actual feathers or scales. These show up as dark spots on the rock but not physical dents.

Kulindadromeus preserved no scales stains, but good impressions of scales. Kulindadromeus preserved lots of feather stains, but no feather impressions.

The baby titanosaur embryos preserve the impressions of scales and no stains of anything. As finds like Kulindadromeus show, this doesn't necessarily mean it didn't also have feathers, because feathers are more likely to be preserved as stains, of which there are none in any known sauropod fossil.

Each type of preservation needs different sediment conditions to work. It seems very, very rare to have both kinds in one fossil. Also, I can think of only a handful of stain fossils that show scales (Psittacosaurus, Kulindadromeus, Sinornithosaurus), and only a handful of impression fossils that show feathers (Archaeopteryx, Sciurumimus). So if the skin sample is an impression, it's less likely to show feathers even if they were there. If it's a stain, it's less likely to show scales even if they were there. By this reasoning, a stain fossil showing scales but no feathers means feathers were probably NOT there. But, an impression fossil showing scales with no feathers tells us very little about presence or absence of feathers. Feathers, especially filaments, almost never show up as impressions, they're just too soft, and you need a stain fossil to tell with any reasonable degree of accuracy whether or not an animal had feathers.

What we need is a baby sauropod from Liaoning or Siberia with stain preservation, to tell us whether or not these animals had both feathers and scales or just scales. Right now it's unknown.

(And we need to be more careful to look out for stain preservation in unexpected places. The Ornithomimus stain-fossil feathers were found by closely examining specimens found a decade ago. People just never thought to look for them).

[Ultimatedinoking]

I have a question. In the past dinosaur eggs have been found and some of them have been known to contain embryos inside. When the preservation was good enough, there were even examples of babies found with skin patches (see below):
http://news.bbc.co.uk/1/hi/sci/tech/216105.stm

If this baby sauropod had feathers or fuzz like some individuals like to think, would it not have exhibited them in this fossil evidence? If it has grown skin at this stage, why hasn't the fuzz/feathers preserved too? Baby birds grow their feathers when they're inside the egg:



Your thoughts.

I doubt sauropods had any fuzz at all.

[Balaur]

I find it more likely that sauropods had feathers than hadrosaurs, because, sauropods are saurischians, and the majority of feathered dinosaurs are saurischians (theropods). I think that in some species, the young were born with feathers, but lost them over time, maybe the sparse covering like an elephant, or some small patches, like on the feet. Just my personal opinion.

[Ultimatedinoking]

I find it more likely that sauropods had feathers than hadrosaurs, because, sauropods are saurischians, and the majority of feathered dinosaurs are saurischians (theropods). I think that in some species, the young were born with feathers, but lost them over time, maybe the sparse covering like an elephant, or some small patches, like on the feet. Just my personal opinion.

There have been found baby sauropods with preserved skin, they who no trace of feathers.

[Balaur]

Some fossil formations can preserve skin, but it doesn't necessarily mean that feathers will be preserved. Also, I don't think all sauropods had feathers. Titanosaurs probably didn't.

[Yutyrannus]

I find it more likely that sauropods had feathers than hadrosaurs, because, sauropods are saurischians, and the majority of feathered dinosaurs are saurischians (theropods). I think that in some species, the young were born with feathers, but lost them over time, maybe the sparse covering like an elephant, or some small patches, like on the feet. Just my personal opinion.

There have been found baby sauropods with preserved skin, they who no trace of feathers.

That was just barely explained a few posts earlier.