Re: Warm-Blooded debate

[NJPharris@aol.com]

In a message dated 97-06-25 20:58:07 EDT, Dinogeorge writes:

> << Well, no, not really, because there are animals out there today
(monotremes
>   and a few types of eutherians) that are endothermic and have a four-
> chambered
>   heart but have only a "semi-improved" stance! >>
>  
>  Here would be an example of a reversal: their ancestors would have had the

> erect stance, and it would have been lost in their modern descendants after

> the endothermy and the quadricameral heart evolved.

On what evidence do you base this assertion?  Since sprawling is primitive
for Amniota, and since the mammalian sprawlers are from lineages that
branched off early (insectivores, monotremes) and are locomotorily rather
unspecialized, it seems more parsimonious to me to think that sprawling is a
primitive trait.

NP