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Re: Jurassic genitals and early humans



I'm not even on the Paleoanthropology list nor read any literature anymore , so 
I
would not argue further about Cro Magnon man.

I thought that might be the case regarding cloaca.  I brought this up to raise 
the
issue of conservation of water.  GI  and urinary losses in animals with cloaca 
are
AFAIK less than mammals.  So if dinosaurs did not sweat and had relatively small
GI and urinary losses then most of their insensible water loss would be
respiratory.  In a hot humid world this would be little as well.

When do the first external genitalia occur in the fossil record?

Michael Teuton

Thomas R. Holtz, Jr. wrote:

> >Do we know that dinosaurs had cloaca?
>
> With Scipinoyx: yes.  Also, there is absolutely no reason to expect they
> didn't, and every reason to suspect they did.  ALL modern sauropsids
> (turtles, lepidosaurs, crocs, and birds) AND the most primitive modern
> mammals (monotremes: in fact, the fact they have a cloaca is where they get
> their name: Monotremata = one opening) have this state, so it is almost
> assuredly the ancestral condition for amniotes.  Only therian mammals among
> amniotes divide the digestive and the urogential openings.
>