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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.