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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,292 Views)
heliosphoros
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Incinerox
May 6 2016, 05:31 AM
heliosphoros
May 5 2016, 10:39 PM
Yi Qi
May 5 2016, 07:33 PM
heliosphoros
May 5 2016, 02:50 PM
I am serious. Varanopsids are outside the clade that includes sphenocodontids + therapsids.
Varanopidae are part of the greater Eupelycosauria, being sister clades to Both Edaphosauridae and Sphenacodontia. They may be outside of the later, but they are close enough in that we can probably infer their integument in the earliest of Sphenacodontians by parsimony.

Yet sphenacodontians not only are closer to therapsids, but also display traits absent in varonopsids (upright gaits, heterodont dentition, et cetera), so it's entirely possible that several factors in regards to their integument don't match up.

For all we know, sphenocaodontians might have already developed fur
By your logic, Megalosauroids were more closely related to chickens than they were to basal ceratosaurs.

But clearly, two branches are much further apart than the roots of a tree and its crown.

Why yes they are. They diverged from chickens more recently than they did from certaosaurs. Learn phylogenetics, plz.
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heliosphoros
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Yi Qi
May 5 2016, 11:29 PM
heliosphoros
May 5 2016, 10:39 PM
Yi Qi
May 5 2016, 07:33 PM
heliosphoros
May 5 2016, 02:50 PM
I am serious. Varanopsids are outside the clade that includes sphenocodontids + therapsids.
Varanopidae are part of the greater Eupelycosauria, being sister clades to Both Edaphosauridae and Sphenacodontia. They may be outside of the later, but they are close enough in that we can probably infer their integument in the earliest of Sphenacodontians by parsimony.

Yet sphenacodontians not only are closer to therapsids, but also display traits absent in varonopsids (upright gaits, heterodont dentition, et cetera), so it's entirely possible that several factors in regards to their integument don't match up.

For all we know, sphenocaodontians might have already developed fur
If by Sphenacodontians you mean Therapsids then yes, we know that atleast SOME therapsid groups most definately had fur by studies of late and middle permian coprolites IIRC

We also know some therapsids like Dinocephalians were mostly covered on bare, hippo like skin, like Estemmenosuchus, pushing the development of fur to somewhere on the post dinocephalian horizon.

However if you mean Sphenacodontid then, its unlikely, the pressure for the development of fur was likely the sudden mid to early late permian cooling of the earth (Megawhaiitsia,Inostrancevia and Scutosaurus's habitat looked VERY differently than what the media depicts, it was by all means a very cold, temperate and high altitude habitat.), long after Dimetrodon and its ilk have gone extinct.

Vibrissae (Whiskers) however, which by all accounts likely preceded fur by at the very least a few tens of millions of years, could very likely be present in both Sphenacodontids and most therapsid groups though.

Estemmenosuchus is probably not a good model since A) it was semi-aquatic, B) no recent descriptions of its skin impressions exist. Fur could have appeared before or after dinocephalians, but we will NEVER know for sure.

Non-therapsid sphenacodontians already had many traits associated with more derived synapsids or even mammals. Fur would hardly be a surprise at this point.
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heliosphoros
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Also, must thank several likers for the evasion. Cowardice validates my views.
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Yi Qi
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Ok, point taken, just remember not to triple (or double) post, as it is against the rules. When you want to add to a point, just edit your post. just leaving a verbal warning here.
Edited by Yi Qi, May 6 2016, 03:20 PM.
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stargatedalek
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I'm not slow! That's just my moe!

heliosphoros
May 6 2016, 02:20 PM
Also, must thank several likers for the evasion. Cowardice validates my views.
I simply preferred to let someone who knew more about this subject do the speaking instead.

This just seems like a huge unknown honestly, especially since Estemmenosuchus impressions don't indicate anything in general.
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CyborgIguana
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It's not like bare skin by itself indicates a lack of integument anyway. It just means said integument rotted away before the animal could be buried.
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Yi Qi
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CyborgIguana
May 6 2016, 09:56 PM
It just means said integument rotted away before the animal could be buried.
Considering we are dealing with a primarily semi aquatic animal, i'd say that's unlikely. I mean, to estemmenosuchus atleast, your consideration is spot on to other therapsids though.
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CyborgIguana
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Yeah, didn't say it applied to Estemmenosuchus specifically.
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Incinerox
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Āeksiot Zaldrīzoti

As much as I'd like to keep debating the complete unknown that is sphenacodont integument, I have far more pressing issues to deal with:

If you have a paleoenvironment where 50% of the known animal species there are oviraptorines (I'm currently looking at 5 goddamn oviraptorines, a therizinosaur, a hadrosaur, a euhelopodid, and a tyrannosaur), and it's supposedly quite arid, what would the comparatively high oviraptorine count mean for the environment as a whole?

Like, what kind of flora was there? Why was it so favourable to oviraptorines? The only thing it explains is why the tyrannosaurid in question is built like it is.

Now, I ask specifically on floras because there are none currently preserved. Which isn't helpful.

Trying to keep this sorta vague because it's for small project of mine that certain people aren't supposed to know the details of yet.
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BossAggron
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Formerly Dilophoraptor

We should keep in mind just how much Integument can vary within a small group, like, look at humans and other apes, or Elephants, Yaks and cattle, so it's very possible that one genera could have fur and another be bare.
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Acinonyx Jubatus
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I AM THE UNSHRINKWRAPPER!

Yi Qi
May 6 2016, 10:59 PM
CyborgIguana
May 6 2016, 09:56 PM
It just means said integument rotted away before the animal could be buried.
Considering we are dealing with a primarily semi aquatic animal, i'd say that's unlikely. I mean, to estemmenosuchus atleast, your consideration is spot on to other therapsids though.
What evidence is there that Estemmenosuchus is semiaquatic?
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Yi Qi
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Acinonyx Jubatus
May 7 2016, 01:24 AM
Yi Qi
May 6 2016, 10:59 PM
CyborgIguana
May 6 2016, 09:56 PM
It just means said integument rotted away before the animal could be buried.
Considering we are dealing with a primarily semi aquatic animal, i'd say that's unlikely. I mean, to estemmenosuchus atleast, your consideration is spot on to other therapsids though.
What evidence is there that Estemmenosuchus is semiaquatic?
Mainly from its proportions (It has a low slung body typical of semi aquatic animals, think of Teleoceras and modern hippopotami for comparisson) and the fact that it's habitat was essentially a collection of flooded canals and bogs and that most if not all the fossils were found in associated river systems, some even in areas that would've been submerged, meaning this was an animal that spent atleast a good deal of time in the water.

Other semi aquatic animals such as the Biarmosuchian Eotitanosuchus and the Temnospondyl Platyoposaurus are also associated with the same habitat, both also showing obvious adaptation for a semi aquatic lifestyle.
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Incinerox
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Āeksiot Zaldrīzoti

Next question:

We lack data for any and all alioramine arms and hands. Which tyrannosauroid would be the best candidate as an arm substitute of sorts?
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BossMan, Jake
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Son of God

After reading I can say that Alioramus may be closely related to Tarbosaurus so I'd say that's an idea for your base
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babehunter1324
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Not so sure, while Alioramus and Tarbosaurus do share some features in the jaw bones it is generally agreed that those were likely plesiomorphic and Tarbosaurus was more closely related to Tyrannosaurus rex and Lythornax than Alioramini (Maybe Quianzhousaurus change something about that, IDK).

As for the best model for Alioramus forelimbs, I think I would go with an Albertosaurine. The claws themselves could be based in Timurlengia. Also I had recently see some restorations of Dryptosaurus with two fingers (though with huge claws) instead of three, idk what evidence we have in favor or against that*.

(By the way, I was totally positive we knew the forelimbs anatomy of Xiangguanlong, but it turns out we don't, quite a lose when trying to reconstruct Alioramus).

*Edit we have material for Digit I and Digit II but not Digit III, so it's quite possible Digit III was a reduced as in advanced Tyrannosaurines (I doubt it would be missing, considering that even Tarbosaurus had one).
Edited by babehunter1324, May 7 2016, 02:01 PM.
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