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Triassic radiation



There's more to this warmbloodedness and the Triassic radiation, I think (I
hope).
   Bipedalism evolves 230 mya, as well as flight. Both may be the result of
the lightening of the skeleton -- the hollowing out of bone to reduce weight.
Also, air sacs attached to lungs for more efficient breathing to fuel high
metabolic rates and fast running may have evolved at this time, although most
of this is associated with aves. Air sacs also reduce weight in the body
cavity. Ever butcher a chicken? 
   Anyway, we have very light-weight, fast croc-like archosaurs getting up on
longer and longer legs and then on two legs. Pterosaurs take off. The
precusors for avian evolution are already in place. Now comes word of birds
from China evolving earlier in the Jurassic than Archeopteryx (at least
that's what I understand).
   I accept that the mid-Triassic may not be so special a time in the whole
scope of things, but fascinating things are underway. Yes? Trouble is there
is too little information about this time period.  Anyone know any good
reference material on this period?