Re: Synapsids weren't reptiles? I'm confused.

[Dann Pigdon <dannj@alphalink.com.au>]

Erik Boehm writes: 

> Only reptiles have beta keratin - and scales ("reptile type" scales, not the "fish type"), don't know when these evolved, but they are currently diagnostic for synapsids vs sauropsids, and ancestral to the crown group.

Pangolin scales have a mixture of alpha and beta keratins. 

Alpha keratin tends to have a specific elongation of around 100% (elasticity 
and plasticity), while beta keratin is closer to 0%. Pangolin scales have a 
specific elongation of around 15%, so they're actually closer to reptile 
scales in that respect. 

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Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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