Dinosaurs and other prehistoric creatures

[MrSpaceJockey]

Thank you so much Vertigo.  That was extremely interesting, informative, and helpful!  Saving that response.

[Vertigo]

On feathers; what's the current consensus on feathery/fuzzy sauropods and other giant herbivores?

With sauropods, we've only ever found scaly skin. Some palaeontologists think it's only a matter of time before we find some form of proto-feather, but for now that's purely speculative. I'm not sure if we've ever found skin traces from a baby sauropod, which is where I'd expect to find fluff if they ever had it.

Giant ornithischians all had scaly skin, though Triceratops had pores in a small number of its scales that may have anchored quills, similar to Psittacosaurus.

With giant herbivorous theropods, there's not much hard evidence, so most assumptions are based on phylogenetic bracketing (assuming the ability to have feathers due to their presence in a relative). Their size means that they didn't need insulation (unless they lived in a cold region, like mammoths), but they may still have retained feathers for other purposes - ie. for display, or to cover their nests when brooding.

• Deinocheirus must have had at least some feathers, because its tail ends in a bird-like pygostyle, which is only useful for maneuvring long feathers. There's some indication that ornithomimosaurs may have brooded their nests, so if true, it would probably have had long feathers on its arms too.
• Gigantoraptor is part of a family that definitely brooded nests, so very likely had 'wing' feathers to shade their eggs. Some oviraptorosaurs had fans of vaned tail feathers, so those also may have been present.
• Therizinosaurus' integument is entirely mysterious. There are two therizinosaurs known with thick coats, but they were an order of magnitude smaller. They also had pygostyles, indicating a tail fan, but Therizinosaurus is so poorly known that we don't know whether it had one too.

[DoomRulz]

I'm guessing the jury's still out on ankylosaurids, stegosaurids, and hadrosaurs when it comes to feathers?

Not surprised about the herbivorous theropods (which sounds like an oxymoron when I say it aloud). The former two are tied to Coelurosauria.

[Vertigo]

Nah, it's very likely that those three ornithischians were all scales-only. We have skin remains of a young Scelidosaurus, from the family which is ancestral to ankys and stegs, as well as adults from the descendant groups.
Hadrosaurs are completely known at various ages, and they were entirely scaly.

[MrSpaceJockey]

I'm going to repost here a paleontological question I asked on my art thread:

I looked up eagle skulls and such, and it always seemed to me that their eyes would "fit" inside their huge sclerotic rings (if I'm correct).  That is what I've done here for my Velociraptor and Deinonychus, but the eyes look almost too small.  I don't know whether or not I still am misunderstanding the eye-sclerotic ring size correlation, or that the reconstructions I've seen for the dromaeosaurs which have eyes bigger than the sclerotic rings of their skull, are just wrong.

versus




(if you're interested in some of my dinosaur art: http://www.avpgalaxy.net/forum/index.php?topic=51859.0)

[Vertigo]

Yeah, the visible eyeball should be fractionally smaller than the inner diameter of the sclerotic ring.
The reason eyes look so small on dromies is that eye size doesn't increase in direct parallel to body size; birds obviously tend to have much smaller bodies, so their eyes are proportionately larger.
Also, dinosaur heads are more substantial than birds', so the eye appears smaller in relation to the head size as well as the body size. Take a look at that eagle, Deinonychus has about double the proportional skull between its jawline and eyeball.

For an example of both points, take a look at a cat compared with a lion. Both animals have comparable night vision and general acuity, but because the lion is a) much larger and b) has a proportionately bigger head structure, the eyes look a lot smaller. I've never tried measuring the eyes of a cat or a lion, but I'd guess the latter's only a little bit bigger.





(Edit- fixing broken picture)

[MrSpaceJockey]

Thanks for clearing that up!  Drawing dinosaurs in a scientifically accurate manner is a lot more difficult that I thought.  I think I just learned today that the big wing feathers on dromaeosaurs only attach to the forearms (actual scientific terms, like 'primaries' or whatever, escape me). 

Do you actually have a professional job in paleontology, or is this just something you're very interested in? 

[Dark Blade1]

i love trex i loved it since i was a kid.

[DoomRulz]

http://phenomena.nationalgeographic.com/2014/12/01/prehistoric-lizard-had-the-teeth-of-a-dinosaur/

In museums, documentaries, and books, the terrestrial environments of the Mesozoic are often presented as being the sole domain of dinosaurs, with stands of conifers parting just enough to see titanic creatures snarl at each other. It's easy to forget that other forms of life – like some weird little mammals – also thrived at the same time. If we're really going to understand what life was like back then, we need the whole picture. That includes carnivores that competed with the dinosaurs. Strange teeth uncovered at a dinosaur-bearing site in Texas remind us that small, non-dinosaurian predators also carved out a living in the Mesozoic world.

[Ryu]

I have a question:
The illustration above, already obsolete, or T-rex and deinonychus, would have to have the body full of feathers?

[DoomRulz]

I would say yes.

[Gilfryd]

CNN is airing the documentary Dinosaur 13 (2014) tonight.

[DoomRulz]

http://www.washingtonpost.com/news/post-nation/wp/2014/12/08/dinosaur-13-broadcast-on-cnn-unearths-old-drama-over-a-t-rex-named-sue/

Apparently, it's not that good

[DoomRulz]

http://store.steampowered.com/app/322920/

Check this out. A feathered T.Rex in a video game? The times are a-changin' indeed!

[DoomRulz]

https://www.voluminajurassica.org/volumina/article/view/173/153

The fragile legacy of Amphicoelias