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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,270 Views)
YixianIsLoveYixianIsLife
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Incinerox
Sep 1 2016, 04:12 AM
Miocene
Hmmm....... what Location in the Miocene Epoch had the absolute biggest amount of diversity of Predators in it?

North America? South America? Europe? Australia? Asia? Africa? Antarctica?
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heliosphoros
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YixianIsLoveYixianIsLife
Sep 1 2016, 02:09 AM
could it be possible that Ceratopsians that were the size, behavior and ecological role of Chipmunks have existed?

Considering that there were multituberculates, zhelestids and other mammals hogging small herbivore/granivore niches, I'd say "no".
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BossMan, Jake
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I would say either North America or Asia seeing as how they had a wider diversity with Africa being a close second
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YixianIsLoveYixianIsLife
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what place in the Silurian Period had the biggest diversity of Animals in it?
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Incinerox
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Āeksiot Zaldrīzoti

Based on what we know?

The UK, specifically Wales, has the most extensive record for the Silurian. But the eastern seaboard of the US and the Baltic have pretty good data too.
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YixianIsLoveYixianIsLife
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What kind of Animals lived in Silurian Wales?
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Incinerox
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Here's a summary of it all.

Thankfully, wikipedia doesn't actually provide a species list, so I don't have to get so annoyed at what would otherwise be a 20 second google name drop.
Edited by Incinerox, Sep 3 2016, 09:49 AM.
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Acinonyx Jubatus
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Matt Martyniuk's blog post concerning beaks and teeth and how they can't coexist in the same space in the mouth.

We good? We're good.

So, in light of the information divulged in this blog post, explain pterosaurs to me.

Spoiler: click to toggle


I searched the internet and I could only find two restorations (both of the same species) where the teeth were set in flesh, not in a beak, with the beak separate. Why do we insist on drawing such pterosaurs with beaks when their teeth so frequently go right to the tip of their jaws?
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Ulquiorra
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Either Pterosaurs have beak-shaped jaws, not an actual beak or the teeth aren't really teeth, just look at the inside of the beak of a goose, only much more exaggerated.

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CyborgIguana
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No, pterosaur teeth are definitely teeth. I'm not sure what the answer is TBH.
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Acinonyx Jubatus
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Ulquiorra
Sep 3 2016, 02:25 PM
Either Pterosaurs have beak-shaped jaws, not an actual beak or the teeth aren't really teeth, just look at the inside of the beak of a goose, only much more exaggerated.

Posted Image
Posted Image
Posted Image

These are NOT the same structures. At all.

What I want to know is, if most pterosaurs didn't have beaks or only had them at the tip of their jaws, what was the rest of the snout covered in? Was it bare skin? Pycnofibers? Would they have had lips covering their teeth (only for those species whose teeth would fit within lips, but still)?
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heliosphoros
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Pterodactyloid pterosaurs have naked snouts. It's probably just that, which kind of looks like a beak due to conventions. Mark Witton even sinks the teeth into the soft tissue "beak" like in crocodile jaws.

In piscivore pterosaurs, this could make sense, as in aquatic crocodilians. However, terrestrial species probably had lips.
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Acinonyx Jubatus
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heliosphoros
Sep 3 2016, 03:05 PM
Pterodactyloid pterosaurs have naked snouts. It's probably just that, which kind of looks like a beak due to conventions. Mark Witton even sinks the teeth into the soft tissue "beak" like in crocodile jaws.

In piscivore pterosaurs, this could make sense, as in aquatic crocodilians. However, terrestrial species probably had lips.
Do we have fossil evidence of naked skin of Pterodactyloid snouts? Because it strikes me that the only definitive evidence that I know of for non-beak facial tissue is Anurognathids (which aren't the best example since they're highly aberrant) and these show pycnofibers right to the tip of the nose. If this is the ancestral condition for pterosaurs, which I think is likely, wouldn't we expect fluffy snouts instead of naked skin even in derived forms?
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TheNotFakeDK
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In Witton's illustrations at least (which I'd say represent the general look we see in other illustrations), it looks to me that the jaws aren't really covered by a true beak in the sense that they're covered by rhamphotheca. Rather, they seem to be covered by tough, stiffened skin. Martyniuk actually mentions a similar thing in his reconstruction of Hesperornis:

Quote:
 
The toothless, pointed tips would have been solid, normal beak, while the rest would have been more like stiffened skin grading into normal skin and feathers toward the back of the skull.

Some toothed pterosaurs like Rhamphorhynchus and Pterodactlyus even appear to have soft-tissue extentions at the tips of their jaws, which may have been hard and keratinised like rhamphotheca, similar to the situation in Hesperornis outlined in Martyniuk's post.

EDIT:

Quote:
 
Do we have fossil evidence of naked skin of Pterodactyloid snouts?
I'm going to be lazy and quote wikipedia for this, however it cites Witton's pterosaur book as the source so take it as you will

"The head-coats do not cover the pterosaur's large jaws in many of the specimens found so far."

Off the top of my head, I think Sordes might be an example of this distribution.
Edited by TheNotFakeDK, Sep 3 2016, 03:24 PM.
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Acinonyx Jubatus
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TheNotFakeDK
Sep 3 2016, 03:19 PM
In Witton's illustrations at least (which I'd say represent the general look we see in other illustrations), it looks to me that the jaws aren't really covered by a true beak in the sense that they're covered by rhamphotheca. Rather, they seem to be covered by tough, stiffened skin. Martyniuk actually mentions a similar thing in his reconstruction of Hesperornis:

Quote:
 
The toothless, pointed tips would have been solid, normal beak, while the rest would have been more like stiffened skin grading into normal skin and feathers toward the back of the skull.

Some toothed pterosaurs like Rhamphorhynchus and Pterodactlyus even appear to have soft-tissue extentions at the tips of their jaws, which may have been hard and keratinised like rhamphotheca, similar to the situation in Hesperornis outlined in Martyniuk's post.

EDIT:

Quote:
 
Do we have fossil evidence of naked skin of Pterodactyloid snouts?
I'm going to be lazy and quote wikipedia for this, however it cites Witton's pterosaur book as the source so take it as you will

"The head-coats do not cover the pterosaur's large jaws in many of the specimens found so far."

Off the top of my head, I think Sordes might be an example of this distribution.
I understand the biology, but what's the reasoning behind it? Is it artistic license, or based on fossil evidence? There's a big difference between a bird and a pterosaur, and phylogenetic bracketing seems to favour fuzzy snouts.

EDIT: I didn't see your addition. That clears up a lot, though it's certainly not the end of the matter. Thank you! :)
Edited by Acinonyx Jubatus, Sep 3 2016, 03:41 PM.
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