Re: Crocs and such(io)

[zone65@bigpond.com]

David Marjanovic wrote:

> > It's interesting that tooth and jaw characteristics hold less weight 
> > (no
> > pun) than leg posture when determining the criteria for dinosauria.
>
> Crocs _retain_ some tooth & jaw characteristics that have also been 
> retained
> by many toothed dinosaurs. But retained ( = plesiomorphic) characters 
> must
> be ignored. Your five-fingered hands don't mean you're closer to 
> opossums
> than to the one-fingered horses. The leg posture of dinosaurs, 
> however, is
> something new ( = apomorphic), like the placental mode of reproduction 
> that
> links us with horses to the exclusion of opossums which _retain_ a 
> short
> gestation.
>
> The basis for modern taxonomy is evolution. :-)

Splendid points, thanks David. The horse/opossum thing seems familiar - 
worth invoking.

I wonder: when did crocs and dinosauria diverge?

Peter Markmann