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What annoys you about paleontology?; Rant on about moronic theories, complaints, or just animals that annoy you.
Topic Started: Sep 28 2013, 05:04 PM (256,163 Views)
BossMan, Jake
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Son of God

Wait it wasn't? My life has been a lie
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stargatedalek
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I'm not slow! That's just my moe!

CyborgIguana
Apr 8 2016, 10:56 AM
I'm guessing you're gonna hate me for this, but it wasn't? What exactly was it then?
Relatively recent wind tunnel studies have shown Microraptor was aerodynamically suited for fast flight and that it had more than the necessary adaptations for gliding. This doesn't mean that it couldn't glide, by all means it could have but what this shows is that gliding requires a lot less specific adaptations than what Microraptor has.

This most likely means Microraptor was not only capable of but adapted for brief periods of powered flight as opposed to extended periods of gliding. It also shows that the maniraptoran wing evolved independently from flight (which was already presumed but never had solid evidence before).
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Incinerox
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Āeksiot Zaldrīzoti

On the one hand, it only takes a simple stretch of skin between wrists and ankles to get a mammal to glide. So a small deinonychosaur being a bit more competent in the air is hardly surprising.

What I do not get are three things:
1) How does this mean raptor wings are independent features from true avian wings? Or am I misunderstanding something here?
2) The leg wings. Did they finally solve how they were posed in flight in this study?
2) Why have I not seen this paper? Anyone got the link to it? An abstract at least?
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PrimevalBrony
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Youtuber. Combat robotics fan

Incinerox
Apr 8 2016, 10:53 AM
To be fair, I kinda feel like the classics earn their places as... You know... Classics.
True, but then again there are much more glorious dinosaurs that deserve to be classics. Take Acrocanthosaurus as an example. It's like a cross between T.rex and Spinosaurus (if you went by layman's terms that is). What about Kosmoceratops, the Triceratops with so many horns? Achillobator the giant Velociraptor?

And yeah I know I used layman's dinosaurs (layman's dinosaur: noun A dinosaur so well known to the public it is everywhere) to describe them, but then again that's how most people speak about dinosaurs.
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stargatedalek
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I'm not slow! That's just my moe!

Incinerox
Apr 8 2016, 11:55 AM
On the one hand, it only takes a simple stretch of skin between wrists and ankles to get a mammal to glide. So a small deinonychosaur being a bit more competent in the air is hardly surprising.

What I do not get are three things:
1) How does this mean raptor wings are independent features from true avian wings? Or am I misunderstanding something here?
2) The leg wings. Did they finally solve how they were posed in flight in this study?
2) Why have I not seen this paper? Anyone got the link to it? An abstract at least?
1) I may have been mistaken there. Perhaps the implication was that if Microraptor was gliding that indicated an alternate developmental path for dromaeosaur wings.

2) They would have hung downwards as if it was walking.

3) This summary doesn't delve very deep into the implications, it's mostly about the posture portion of the study. Most key is probably this paragraph:
Quote:
 
Notably, Microraptor was never an efficient flier: it suffered from extensive drag in all simulations and was aerodynamically unstable, performing best when moving quickly. It was well able to glide no matter what the feather or wing configuration: in fact, we concluded that all Microraptor needed in order to glide effectively was a flat wing surface – feather asymmetry, anatomy and configuration didn’t make that much difference (Dyke et al. 2013), a discovery which supports the view that the evolution of theropod wing and feather anatomy did not occur within an aerodynamic context.
Since Microraptor performed best at speed and had more than the necessary adaptations for gliding, it follows that powered flight is a reasonable cause of such adaptations (while not ruling out the possibility of gliding, or both).

http://blogs.scientificamerican.com/tetrapod-zoology/flight-of-the-microraptor/

In fairness when I said "When people still claim Microraptor was a gliding animal" I should have said "When people still deny Microraptor was likely capable of powered flight and say it could only glide".

I'm sure someone who's read the actual paper can give a much clearer picture.

*edit*

Quote:
 
The fact that Microraptor was a half-decent glider, but not really a great one (it incurs all that drag, don’t forget), suggests that it was an occasional glider that could indulge in this behaviour, but didn’t rely on it as a specialisation: in other words, it wasn’t an aerial specialist, or a ‘flying squirrel dinosaur’ that spent most of its time leaping from tree to tree, relying on arboreal resources.
Again, a lack of specialization for efficient gliding supports the idea of brief periods of powered flight, for climbing or catching prey, as opposed to using flight or gliding to travel.
Edited by stargatedalek, Apr 8 2016, 02:17 PM.
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Mathius Tyra
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Rat snake is love... Rat snake is life

Well, this is kind of interesting. This would make Microraptoria clade dromaeosaur much more diverse group than before, containing power flight capabling member like Microraptor and then something completely terrestial like Hesperonychus and maybe something in between(flightless arboreal species).
Edited by Mathius Tyra, Apr 8 2016, 02:30 PM.
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stargatedalek
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I'm not slow! That's just my moe!

I wouldn't say Microraptor was flying around very often. More-so that flying is more useful as a "secondary attribute" than gliding, which tends to only be of much use when one relies on it.
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CyborgIguana
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Quote:
 
Take Acrocanthosaurus as an example. It's like a cross between T.rex and Spinosaurus (if you went by layman's terms that is).

I honestly consider T. rex and Spinosaurus to both be more unusual theropods than Acrocanthosaurus (which is a fairly typical allosauroid aside from having somewhat taller vertebrae than most), even if they're better known to laypeople.
Edited by CyborgIguana, Apr 8 2016, 03:15 PM.
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Yi Qi
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Mathius Tyra
Apr 8 2016, 02:29 PM
Well, this is kind of interesting. This would make Microraptoria clade dromaeosaur much more diverse group than before, containing power flight capabling member like Microraptor and then something completely terrestial like Hesperonychus and maybe something in between(flightless arboreal species).
It is pretty widely accepted that Deinonychosauria evolved from flying ancestors, what with the morphology of the Unenlagiine wing and clearly volant forms such as Rahonavis. IIRC the consensus is, derived Deinonychosauria are actually secondarily flightless.
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Acinonyx Jubatus
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I AM THE UNSHRINKWRAPPER!

CyborgIguana
Apr 8 2016, 03:13 PM
Quote:
 
Take Acrocanthosaurus as an example. It's like a cross between T.rex and Spinosaurus (if you went by layman's terms that is).

I honestly consider T. rex and Spinosaurus to both be more unusual theropods than Acrocanthosaurus (which is a fairly typical allosauroid aside from having somewhat taller vertebrae than most), even if they're better known to laypeople.
Right. Acrocanthosaurus is awesome, but not especially unique. Tyrannosaurus, on the other hand, had a massively built skull specially designed for power, with teeth made for smashign and crunching instead of slicing, very much unlike other large carnivorous dinosaurs. In addition, we have dozens of specimens including a largely complete growth cycle, with numerous pathologies and clues to their lifestyle and behaviours- again unlike most other theropods, most of which are known from just a few specimens specimens or isolated fragments. And then of course Spinosaurus was totally unlike everything else in every way- although to be fair, if it hadn't appeared in Jurassic Park III no one would know about it, either.
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CyborgIguana
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Most people who aren't hardcore paleo-fans also don't know just HOW weird Spinosaurus actually was.
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BossAggron
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Formerly Dilophoraptor

I'd figure Acrocanthosaurus being pretty weird in its on right, it has those massive mutton chop like areas on the back of the mandible, and that high spine does give it a weird profile.

It might just be my bias though, Acro is my favorite Theropod at this time.
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heliosphoros
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Yi Qi
Apr 8 2016, 04:27 PM
Mathius Tyra
Apr 8 2016, 02:29 PM
Well, this is kind of interesting. This would make Microraptoria clade dromaeosaur much more diverse group than before, containing power flight capabling member like Microraptor and then something completely terrestial like Hesperonychus and maybe something in between(flightless arboreal species).
It is pretty widely accepted that Deinonychosauria evolved from flying ancestors, what with the morphology of the Unenlagiine wing and clearly volant forms such as Rahonavis. IIRC the consensus is, derived Deinonychosauria are actually secondarily flightless.

Changyuraptor as well, and possibly baby Deinonychus and several other forms in which adults are flightless.
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CyborgIguana
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BossAggron
Apr 8 2016, 07:19 PM
I'd figure Acrocanthosaurus being pretty weird in its on right, it has those massive mutton chop like areas on the back of the mandible, and that high spine does give it a weird profile.
Chances are the high spine wouldn't even have been especially noticeable on the living animal.
Edited by CyborgIguana, Apr 8 2016, 08:17 PM.
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PrimevalBrony
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Youtuber. Combat robotics fan

Acinonyx Jubatus
Apr 8 2016, 05:34 PM
CyborgIguana
Apr 8 2016, 03:13 PM
Quote:
 
Take Acrocanthosaurus as an example. It's like a cross between T.rex and Spinosaurus (if you went by layman's terms that is).

I honestly consider T. rex and Spinosaurus to both be more unusual theropods than Acrocanthosaurus (which is a fairly typical allosauroid aside from having somewhat taller vertebrae than most), even if they're better known to laypeople.
Right. Acrocanthosaurus is awesome, but not especially unique. Tyrannosaurus, on the other hand, had a massively built skull specially designed for power, with teeth made for smashign and crunching instead of slicing, very much unlike other large carnivorous dinosaurs. In addition, we have dozens of specimens including a largely complete growth cycle, with numerous pathologies and clues to their lifestyle and behaviours- again unlike most other theropods, most of which are known from just a few specimens specimens or isolated fragments. And then of course Spinosaurus was totally unlike everything else in every way- although to be fair, if it hadn't appeared in Jurassic Park III no one would know about it, either.
*coughMajungasauruscough*

If you want unique theropods, look at the abelisaurs. Sure T.rex breaks bones in a single bite, but abelisaurs hold their prey in their jaws and slowly crushes them; much more brutal and terrifying than a quick death. Even if they weren't all as big as T.rex (the closest I know is probably Ekrixinatosaurus), their method of attack is much more brutal
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