Re: Amphibians - the comeback kings of evolution

["T. Michael Keesey" <keesey@gmail.com>]

On 1/9/07, Roberto Takata <rmtakata@gmail.com> wrote:
> On 1/9/07, Jeff Hecht <jeff.hecht@sff.net> wrote:
> >
> > The full article 
> http://environment.newscientist.com/article/dn10910-amphibians--the-comeback-kings-of-evolution-.html
>  says the three common ancestors " eventually gave rise to frogs and toads, 
> salamanders, and caecilians (snake-like animals that live underground), respectively." 
> In other words, three original lines of amphibians split about 350 million years ago, each 
> diversified after the Permo-Triassic extinction, and the lines that survived remain distinct 
> today.  Other lines went extinct at various times.
> > --
>
> Is that a right use of term "common"?

It's confusing, but I'm pretty sure they mean "common" respectively,
i.e., an ancestor common to all frogs and toads, an ancestor common to
all salamanders, and an ancestor common to all caecilians. Not three
ancestors common to all three extant groups. Poor wording, it seems to
me.
--
T. Michael Keesey
The Dinosauricon: http://dino.lm.com
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