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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,435 Views)
CyborgIguana
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It's possible, but rather unlikely IMO.
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Rush2112
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I'm only just entering this, but basically a footprint to an animal similar in size and gait was discovered in Alask? To be honest it was only a matter of time. Cold weather digs are finally becoming more available and I would be surprised not to see evidence of this migration along the migration route.
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CyborgIguana
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I highly doubt this is indicative of a migration, since this footprint is separated from those of Nothronychus by over 20 million years.
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Taurotragus
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How did Paleogene and Neogene periods divide the Tertiary period(yes I know the term is outdated)?
And what's the likeliness of Abelisaurids having small spines on their backs similar to the ones diplodocus had?
Edit:Figured out the first question, still need an answer to the second question.
Edited by Taurotragus, Dec 13 2014, 03:02 PM.
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Rush2112
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No no, the migration from Asia to North America, not a Nothronychus migration from New Mexico. Sorry for the ambiguity. :P Until now it has been assumed that the Asian species traveled over the Alaskan land bridge and now we have some (quite literally) hard evidence.
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CyborgIguana
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Oh, sorry. This would indeed be evidence of such a phenomenon.
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Furka
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How many chances are there that Ceratosaurus nasicornis and C. dentisulcatus are the same species ?
Wiki doesn't really help on the matter, and Hartmann says it's possible to him, but it's just an opinion.
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DinoBear
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Decently high, I say. C. dentisulcatus has the only known material of an adult Ceratosaurus , which means that even if it was distinct it would be our best model for an adult nasicornis
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Yutyrannus the second
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How do accurate Sauropods, Stegosaurids, Ankylosaurs, Ceratopsians and Pachycephalosaurians actually look like?
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CyborgIguana
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Well, considering just how diverse all the dinosaur families you just brought up are, that's a difficult and rather vague question to answer.
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Rush2112
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That is tough. Ceratopsids are incredibly dverse. Large with horns (Triceratops), small with no horns (Protoceratops), medium sized with spikes (Styracosaurus). That's just a few. Don't even get started on Sauropods...
Definately need specifics.
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Incinerox
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Āeksiot Zaldrīzoti

...

Each one of those would require ESSAYS to answer...
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Bill
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originally, one_piece

here's a more specific question. i want to completely clear myself of how a triceratops look, we can mostly agree on it's shape, but the quills are what cause debates. any paleo fan can pretty much agree that triceratops likely to have quills, but exactly how much? and where? i see dozens of re-construction with different quills formation, like this with long quills like porcupine:

Posted Image

some are rather smaller and less dense:

Posted Image

and some look more like spikes rather than quills:

Posted Image

and i think i saw a reconstruction with fully coated quills too. so which one of them is the more plausible? and why?
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Incinerox
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Āeksiot Zaldrīzoti

The last one by far.

The "quill" hypothesis shown in the other two are based off the ones present on Psittacosaurus's tail, and the presence of unusual round, knob shaped scales on trike skin. The problem is that the quills of psittacosaurus are totally different structures which erupted from the skin differently. They weren't supported by knob shaped scales, they were arranged in a more typical bristle like manner (as opposed to sparsely arranged large scales), and they were arranged in a single row over a portion of the tail (which again, is not what you see in trikes).

Then you have to consider that trikes are the exception to a fairly well documented rule. Other chasmosaurines and all known centrosaurine skin show the right mosaic type scales, and the right arrangement of larger, round scales, but only trike has modified their round scales into weird, protruding things. What separates them from psittacosaur quills is that they're full on scales. They aren't frayed scales like Kulindadromeus. They aren't long, thin bristles like psittacosaurus. They're genuine, solid scales.

The thing is that we have no idea if the scales served as a supporting structure for a bristle (which is completely undocumented in other animals), or if they just looked like that in life. But the quill hypothesis is tenuous and based entirely on "this very primitive species had it" rather than looking to its closer, quill-less relatives. You also find that quills and genrally feathered structures tend to be associated with a certain type of scaly texture, one that psittacosaurus had, Kulindadromeus had, theropods had, but NOT seen in trike mummies.

My personal line of thinking is that if you consider the 65 million years it spent being worn down and emaciated, it's likely those scales could have looked a bit fuller and perhaps sharper too. A bit like some well armed lizards today, only maybe not as extreme.
Posted Image
Posted Image

I think I had a rant about this very topic before somewhere on this very forum. If I find the post, I'll forward you to it.
Edited by Incinerox, Dec 29 2014, 05:20 AM.
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Bill
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originally, one_piece

nice answer! noted! is there any article about the skin impression of the trike that you can link me to? google is not very helpful when it comes to paleontology :/
Edited by Bill, Dec 29 2014, 08:17 AM.
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