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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,323 Views)
Incinerox
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Āeksiot Zaldrīzoti

I'm not aware of any major size differences between Pachyrhinosaurus pretorum, Ugrunaaluk and their relatives further south. Only Nanuqsaurus. The unidentified troodontid there seem to have gotten MUCH larger than its southern relatives, which I thought was a response to being in a colder, generally more miserable climate (it apparently would have been very similar to the UK in terms of how stereotypically gray and miserable the weather was, my reading tells me).

I was also under the impression that Prince Creek was actually early Maastrichtian - 67Ma? Making it essentially a final stronghold for Horseshoe Canyon fauna when it got replaced by Hell Creek's stuff in the south.
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BossMan, Jake
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Son of God

The Prince creek dates from between 80-60 mya but the fauna best known from this time were from between 71-68 mya<--That may be wrong by like a million years but its close enough.

One thing I always remember about Troodon was that is lived til the end of the cretaceous. Its fossils have been found in Hell Creek (at least the teeth have been) however the wikipedia page says that that they only lived between 77.5-74.8 mya. Is that correct and if so what happened to the associated Troodon fossils from the last stages of the Maastrichtian?

And at some point in the Maastrichtian did T-rex live along side Alamosaurus and if so where?
Edited by BossMan, Jake, Jan 22 2016, 10:04 AM.
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Furka
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IIRC the Hell Creek material has been reclassified as Pectinodon (making the genus valid again).
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Incinerox
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Āeksiot Zaldrīzoti

BossMan, Jake
Jan 22 2016, 10:01 AM
The Prince creek dates from between 80-60 mya but the fauna best known from this time were from between 71-68 mya<--That may be wrong by like a million years but its close enough.
Well if we're gonna narrow it down even further, it appears we're looking at exactly 69.1Ma.

Wikipedia specifically refers to Troodon formosus as living 77.5 and 76.5 million years ago in Montana and Alberta (Judith River and Oldman Formations respectively). It's very likely that all these specimens from other locations, namely Prince Creek, Hell Creek, Two Medicine, Horseshoe Canyon, Javelina etc. represent either different species within the genus, or different genera entirely, as is the case with Pectinodon, maybe even Stenonychosaurus.

Honestly, the fact that Troodon's holotype is a single tooth might actually render the whole genus as invalid at some point.
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CyborgIguana
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BossMan, Jake
Jan 22 2016, 10:01 AM
And at some point in the Maastrichtian did T-rex live along side Alamosaurus and if so where?
There's tyrannosaurid material from the Javelina formation that's been attributed to Tyrannosaurus rex IIRC, though it might turn out to be a different genus.
Edited by CyborgIguana, Jan 23 2016, 01:39 PM.
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54godamora
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what kind of feather coating did therizinosaurus have?
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Paleop
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Paleopterix

while no direct feathers have been found on therizinosaurus itself, beipiaosaurus had either stage 1 or 2 feathers so essentially somewhere in appearance between hair and down.

these may help you ;)
Feathers: Your Dinosaurs Are Wrong #15
Therizinosaurus: Your Dinosaurs Are Wrong #11
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Furka
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Could all sauropods perform rear kicks like this, or was it a feature exclusive only to some groups ?

Posted Image
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Incinerox
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Āeksiot Zaldrīzoti

Honestly I don't know why kicking was the first thing that popped into their heads. It seems to me that it was more an adaptation for a certain kind of terrain.
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BossMan, Jake
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Son of God

Is it possible that for a very short time in history that Albertosaurus and T-rex coexisted?
They have both been dated from 68 MYA and are known from Alberta. Was is possible or is that to far fetched.
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Furka
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It depends if environmental changes didn't wipe out Albertosaurus right before Tyrannosaurus arrived.
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babehunter1324
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Which I think is exactly what happened.

I'm quite positive than the envioriment of the area changed massively throught of the Maastritchian, early on it was likely warmer and more humid because the WIS was still very extensive, however by the middle of Maastritchian the WIS was receeding quicky which likely caused a massived reduction in the extension of coastal swamps and forests that were so typicall of the Horseshoe Canyon Formation and then were substituted by drier and colder (although still temperate) forests seen in the Scollard Formation.
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Incinerox
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Āeksiot Zaldrīzoti

Assuming that were true, you'd actually find that the last of Albertosaurus remains were further south-east than the norm (as the sea regressed eastward and the continent cooled, Albertosaurus would have likely been restricted to following the last pockets of warm swampland further south and east until their survival was no longer viable.

I'd be interested to see if or how that plays out in the fossil record in due time.
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54godamora
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what animals sans troodonts could se well in low light and live on land.
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CyborgIguana
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Anurognathids must've been able to see pretty well in the dark, since they had proportionally larger eyes than most other pterosaurs and were almost certainly nocturnal/crepuscular.
Edited by CyborgIguana, Jan 25 2016, 07:21 PM.
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