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Post by Runic on May 28, 2013 2:37:12 GMT 5
it is often unwise to make statements about morphology not based on anatomy but concluding from phylogeny. It is true the majority of dinosaurs and reptiles had rounded claws. However reptiles are a damn diverse group, and there are always exceptions. Most mammal claws aren't sharpn either. You can be as diverse as you want to be. There are still only two type of claw sheaths, Helical and Pleated. You can't use being general as an excuse. EDIT: Unless you can name one extant reptile (including birds) with helical keratin claws? Or mammal with pleated keratin claws?
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Post by theropod on May 28, 2013 15:03:45 GMT 5
The types of ceratine don´t necessarily have any implycationn for shape, or is there evidence for that?
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Post by Runic on May 28, 2013 20:39:38 GMT 5
The types of ceratine don´t necessarily have any implycationn for shape, or is there evidence for that? Uh yea. Looking at them. Pleated keratin claws are almost always thicker and larger.
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Post by Runic on May 28, 2013 20:41:56 GMT 5
But theropod good news. Reptiles and birds have B-Keratin (the stronger of two types) so generally reptiles claws and horns are stronger.
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Post by theropod on Jun 1, 2013 15:12:42 GMT 5
Not "almost always", that can by explained by phylogeny and ecology. Is that obligate because of mechanical function of the type of ceratine (is this ceratine unable to form sharp edges), or is it not?
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Post by Runic on Jun 1, 2013 18:42:43 GMT 5
Not "almost always", that can by explained by phylogeny and ecology. Is that obligate because of mechanical function of the type of ceratine (is this ceratine unable to form sharp edges), or is it not? A sharp edge alone does not make a efficient cutting weapon otherwise cats would be ripping apart everything they attack.
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Post by theropod on Jun 1, 2013 18:58:52 GMT 5
Have I said a sharp edge alone would make an efficient cutting weapon?
It is definitely necessary to cut tough. Cat claws can cause horrific lacerations. Now assume the claws of dromaeosaurs were sharp on the inside. They could first puncture deep and then rip things open, or do so in a kicking motion.
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Post by Runic on Jun 1, 2013 19:05:30 GMT 5
Have I said a sharp edge alone would make an efficient cutting weapon? It is definitely necessary to cut tough. Cat claws can cause horrific lacerations. Now assume the claws of dromaeosaurs were sharp on the inside. They could first puncture deep and then rip things open, or do so in a kicking motion. You were the one that seemed to have implied that as you quoted me for saying drom claws weren't good at cutting. Cats claws are thinner than droms thus one could infer the hook shape of their claws would aid much better in cutting. The claws of drom were barreled like todays birds of prey and varanids. They were suited for grappling via multiple stabbings. They weren't too good at ripping unless you mean they did it with a motion of a downwards jerking motion after they stabbed their attacker or prey?
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Post by theropod on Jun 1, 2013 22:23:17 GMT 5
My point was that dromeosaur claws were not barrel-shaped, their cores are quite flat actually, and that being longer and suited for stabbing deep and get more than just a superficial hold they would be much better at inflicting large lacerations than cat claws.
And yes, I suggest they would first stab and then emply such a motion to maximize the damage they do.
The muscles for pronation of the leg are some of the strongest in the body, these could be used for that motion without difficulty.
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Post by Runic on Jun 2, 2013 23:09:21 GMT 5
My point was that dromeosaur claws were not barrel-shaped, their cores are quite flat actually, and that being longer and suited for stabbing deep and get more than just a superficial hold they would be much better at inflicting large lacerations than cat claws. And yes, I suggest they would first stab and then emply such a motion to maximize the damage they do. The muscles for pronation of the leg are some of the strongest in the body, these could be used for that motion without difficulty. WITHOUT the keratin sheath THE CORE ISN'T BARRELED! I told you this twice already! Animals with pleated keratin have barrel shaped keratin sheaths. Their claws are generally larger and thicker than animals with helical keratin sheaths. And you don't seem to understand the difference between a laceration and a stab. Droms did not lacerate their prey, there are countless papers stating and explaining this. They stabbed them, which is a major difference. A cats claws has a higher chance of cutting something up than a droms simply due to the shape. Droms didn't lacerate, the stab. You want evidence? Look at modern birds of prey.
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Post by theropod on Jun 2, 2013 23:11:36 GMT 5
We are running in circles; How do you know what shape the ceratine had without even having a look at the cores of other claws?
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Post by Runic on Jun 2, 2013 23:24:29 GMT 5
We are running in circles; How do you know what shape the ceratine had without even having a look at the cores of other claws? Because the CORE of the claw doesn't infer whether the claw was thin or not. It's the keratin type that does. Pleated keratin clawed harpy eagle, helical keratin clawed lion I want you to compare the thickness, length, and shape of the claws. I can't find a good image of a bear or wolverines claws however it should be noted their claws are thicker due to a forager and digging lifestyle.
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Post by theropod on Jun 2, 2013 23:26:08 GMT 5
And how do you know it is not the core shape or use but the type of ceratine? Who stated the type of ceratine found in sauropsids is unable to form a narrow, sharp-edged claw?
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Post by Runic on Jun 2, 2013 23:32:35 GMT 5
And how do you know it is not the core shape or use but the type of ceratine? Who stated the type of ceratine found in sauropsids is unable to form a narrow, sharp-edged claw? You never seem to grasp what I say. So I will just blatantly say it and maybe you will get it. PLEATED keratin is generally thicker, longer, and larger all around stronger than helical keratin. However they are not great at slicing up something. Helical keratin is generally smaller and weaker than pleated keratin. However you are comparing the cutting capabilities of a drom to a cat which is not very good as the muscle attachments to each limb housing the claws as well as the claw shape and type serve extremely different purposes. Dromaeosaurs use their claws for pinning prey, grappling and stabbing them. Cats use them for grappling almost solely but their claws are more hooked therefore a cat attacking you has a higher chance of shredding you apart than a same sized drom the latter of which will most likely stab you multiple times or pin you under its weight to eat you alive.
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Post by theropod on Jun 2, 2013 23:41:05 GMT 5
Actually nobody has a proof what they were used for in dromaeosaurs, unless you are implying Jurassic Park came true (in that case please have the kindness to tell me where, so that I can go there!).
What about bird's beaks. Shouldn't they too be made out of pleated keratin? Some are/were pretty sharp edged...
You still haven't told me whether there is some functional reason, or whether you are just observing in your tiny sample the animals don't have sharp-edged claws. i suspect the latter at the moment.
But my feeling tells me you just want to have an entertaining debate.
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