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Re: Comments on _Longisquama_ in _Science_.
In a message dated 6/28/00 4:39:21 PM, firstname.lastname@example.org writes:
<< Endothermy in tuna, billfish and lamnid sharks (e.g. great whites,
porbeagles and makos) evolved independently (Block, B.A., and J.R.
Finnerty 1994 Environmental Biology of Fishes 40: 283-302). Tuna and
lamnid sharks are systemic endotherms (the whole body temperature is
raised), while billfish heat only the eyes and brain by the action of
specialized "heater" eye muscles. Thus endothermy in billfish and great
whites is functionally quite different.
Quite right. However it does indeed show that endothermy is something that
has evolved many times in vertebrates.