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avatar_Takama

Edmontosaurus gets a crest.

Started by Takama, December 12, 2013, 06:44:49 PM

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Blade-of-the-Moon

Quote from: tyrantqueen on December 27, 2013, 05:04:04 PM
Quote from: Simon on December 27, 2013, 04:48:52 PM
As far as Pterosaur crests go, I can't imagine that they were not used in flight.  Given the intricacies of flight, having a large surface like a crest would either be useful or detrimental in flight - you can't hide them from the wind. If detrimental, it would not have been selected for genetically. 

Given that it was located on top of the maneuverable, swiveling head, a crest was in an optimal location to be used as a control surface.  I would think that it would have improved maneuverability in flight...

...just a laymen's 2 cents' worth ...
Not necessarily. Hornbills evolved a big crest (casque) and a brightly coloured beak for sexual attraction, even though it intrudes with their vision field.

I don't think it would impair vision since most pterosaur crests extend from the middle of their skulls to the back of the head ?


tyrantqueen

#41
Quote from: Blade-of-the-Moon on December 27, 2013, 05:12:28 PM
Quote from: tyrantqueen on December 27, 2013, 05:04:04 PM
Quote from: Simon on December 27, 2013, 04:48:52 PM
As far as Pterosaur crests go, I can't imagine that they were not used in flight.  Given the intricacies of flight, having a large surface like a crest would either be useful or detrimental in flight - you can't hide them from the wind. If detrimental, it would not have been selected for genetically.

Given that it was located on top of the maneuverable, swiveling head, a crest was in an optimal location to be used as a control surface.  I would think that it would have improved maneuverability in flight...

...just a laymen's 2 cents' worth ...
Not necessarily. Hornbills evolved a big crest (casque) and a brightly coloured beak for sexual attraction, even though it intrudes with their vision field.

I don't think it would impair vision since most pterosaur crests extend from the middle of their skulls to the back of the head ?
That's not what I meant. The point behind my hornbill comparison was that some organisms do evolve features that don't make sense at first from an evolutionary standpoint, or seem detrimental...but actually the need for sexual display usually takes precedence.

Gwangi

You're talking about sexual selection vs. natural selection. This same sort of evolution is what is responsible for things like a peacocks tail. While it greatly impairs the bird, the peahens like it and so it is passed on regardless of the added handicap. Bright colors could be lumped in as well since something like a male cardinal or mallard drake will stand out to any predator and make it more vulnerable. If an animal can survive with this kind of handicap long enough to reproduce, his genes (for it is generally the males with the sexual display) must be something worth while. I feel fairly confident that this is where most pterosaur crests come from especially since at least in the case of Pteranodon there is clear sexual dimorphism.

tyrantqueen

Quote from: Gwangi on December 27, 2013, 09:41:16 PM
You're talking about sexual selection vs. natural selection. This same sort of evolution is what is responsible for things like a peacocks tail. While it greatly impairs the bird, the peahens like it and so it is passed on regardless of the added handicap. Bright colors could be lumped in as well since something like a male cardinal or mallard drake will stand out to any predator and make it more vulnerable. If an animal can survive with this kind of handicap long enough to reproduce, his genes (for it is generally the males with the sexual display) must be something worth while. I feel fairly confident that this is where most pterosaur crests come from especially since at least in the case of Pteranodon there is clear sexual dimorphism.
Yes, that's it :)

Gwangi

And now I'm wondering if this Edmontosaurus crest is a smaller female version of a much larger and showier male version? We may never know...or we might find out tomorrow. Fun stuff.

Blade-of-the-Moon

Quote from: Gwangi on December 27, 2013, 11:35:03 PM
And now I'm wondering if this Edmontosaurus crest is a smaller female version of a much larger and showier male version? We may never know...or we might find out tomorrow. Fun stuff.

lol darn..just more fuel for the imaginative fires !  ;D

Brachiosaurus

I can't wait to find out more about these things and I can't wait for someone to mod their Deinocheirus with a sail and their edmontasaurus with a fleshy crest

Dinoguy2

Quote from: Zopteryx on December 27, 2013, 05:25:30 AM
Quote from: Blade-of-the-Moon on December 27, 2013, 04:41:57 AM
Interesting. I'm not sure if we have any evidence for crest size based on sex do we?
Amongst dinosaurs, only Parasaurolophus comes to mind, but I don't know if the gender of short-crested individuals has ever been determined.  In pterosaurs, it is generally accepted that Pteranodontids females were virtually crestless, in addition to being smaller.  Conversely, the same does not appear true in birds; while males are often more flamboyant than females, I can't think of any crested species in which the females lack a crest. ???

Regarding Parasaurolophus, all the short-crested specimens come from a different formation/time period than the long-crested ones, an are nowadays almost always considered a distinct species rather than a sexual dimorph. (P. cyrtocristatus).
The Carnegie Collection Dinosaur Archive - http://www.dinosaurmountain.net

Splonkadumpocus

Quote from: Brachiosaurus on January 07, 2014, 10:36:29 PM
I can't wait to find out more about these things and I can't wait for someone to mod their Deinocheirus with a sail and their edmontasaurus with a fleshy crest

I'd personally like someone to do a full 1:40 Edmontosaurus regardless of crest. For one of the most common contemporaries of Tyrannosaurus and Triceratops, it's barely represented at all. Safari did do a good one a couple of years ago, but it needed to be bigger.

Although I guess since hadrosaurus with big flashy headgear tend to be made into figures more often, this discovery might lead to somebody giving Edmontosaurus the treatment it deserves.

Gwangi

Quote from: Splonkadumpocus on February 07, 2014, 01:51:04 AM
Quote from: Brachiosaurus on January 07, 2014, 10:36:29 PM
I can't wait to find out more about these things and I can't wait for someone to mod their Deinocheirus with a sail and their edmontasaurus with a fleshy crest

I'd personally like someone to do a full 1:40 Edmontosaurus regardless of crest. For one of the most common contemporaries of Tyrannosaurus and Triceratops, it's barely represented at all. Safari did do a good one a couple of years ago, but it needed to be bigger.

Although I guess since hadrosaurus with big flashy headgear tend to be made into figures more often, this discovery might lead to somebody giving Edmontosaurus the treatment it deserves.

I believe the Schleich Edmontosaurus is in the 1:40 scale range. It's a great model IMO from Schleich's better days. It can be hard to find though.
http://dinotoyblog.com/2009/04/23/edmontosaurus-schleich/


HD-man

#50
Quote from: Zopteryx on December 27, 2013, 03:39:53 AM
Not so fast!!!

This artist makes a very valid point:
http://www.deviantart.com/art/Edmontosaurus-annectens-and-the-Crest-That-Wasn-t-422326269

I'm glad I'm not the only 1 who isn't completely sure.

Quote from: tyrantqueen on December 27, 2013, 03:52:22 AMWould the females have had a crest? If not, then Safari's Edmontosaurus works pretty well in that regard.

If Edmontosaurus combs were anything like chicken combs (which ppl have been comparing them to), then I'm guessing that the female had a "tiny, non visible comb or no comb" ( http://sgphilgoh.hubpages.com/hub/Red-Jungle-Fowl ).
I'm also known as JD-man at deviantART: http://jd-man.deviantart.com/

HD-man

#51
Quote from: Blade-of-the-Moon on December 27, 2013, 03:57:12 PMThat species is what first came to my mind, but I've never heard anything as what gender they are..actually that goes for any dinosaur really. Last I read we still aren't sure what differentiates the sexes among them based on fossil evidence.

Barden 2011 ( http://aps.group.shef.ac.uk/level-4-web-sites/l4-students-09/barden-holly/4th-year-dissertation.pdf ) is a good review for non-avian dinos in general. As for hadrosaurs in particular, there's Parasaurolophus & Lambeosaurus (See the Holtz quote).

Quote from: Blade-of-the-Moon on December 27, 2013, 03:57:12 PMIsn't it still accepted that pterosaurs crests could have aided in flight ? That would be an odd adaptation if the females didn't have one at all right ?

There's a paper about that ( http://epub.ub.uni-muenchen.de/12012/1/zitteliana_2008_b28_10.pdf ). To quote Elgin et al., "The results show that, while a crest assists in lowering the yawing moment of the head and limiting the movement of the centre of pressure, the overall aerodynamic effect is modest. The crest most probably evolved independently of any aerodynamic function, other than to maintain their streamlined profile for reducing drag, and presumably served primarily in either intraspecific sexual displays and/or species recognition."

Quoting Holtz (See "HADROSAURIDAE": http://www.geol.umd.edu/~tholtz/G104/lectures/104ornithop.html ):
QuoteDifferences in crest size and shapes within some populations may reflect sexual and/or ontogenetic variations.



I'm also known as JD-man at deviantART: http://jd-man.deviantart.com/

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