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Re: Archosaur Origins...was:MESENOSAURUS ERRATA.



In a message dated 8/25/01 8:00:35 AM EST, ELurio writes:

<< Permian? I don't think so. There were NO archosaurs until just before the 
P/Tr boundry, and we know that insulatory integuments didn't evolve until 
later, as we know from skin impressions. [Walking on Eggs has some nice 
photos of baby suropod skin] >>

The P/Tr archosaurs (one genus as far as I know: Archosaurus) had to evolve 
from something: earlier archosaurs. According to my simple definition of 
Archosauria, prolacertiforms are basal archosaurs. And don't forget to allow 
for secondary loss of feathery integument in the larger animals, perhaps for 
the same reasons that rhinos and elephants lose most of their hair.