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Re: Tetrapod note (was: Re: [Re: Resting Sauropods])



Jonathan R. Wagner wrote:

> Date: Thu, 16 Jul 1998 10:41:36 -0700
> Ralph Miller III wrote
> >So, as you can see, the colloquial (dictionary) meanings of "tetrapod" and
> >"reptile" differ markedly from the cladistic meanings.  And it is proper to
> >refer to a bird as a "reptile" and a "tetrapod," whether you feel
> >comfortable with such labels or not.
>         I was under the impression that in general
> biological/paleobiological circles (irrespective of cladistics), birds and
> snakes were considered tetrapods, as tetrapod referred to animals which
> share a four limbed heritage. Thus, amniotes, lissamphibia, and everything
> down to something like _Ichthyostega_ were all tetrapods. Was I wrong?

According to common sense, you're correct.

According to the Tree of Life, you're wrong.

"Recently, Tetrapoda was formally defined as a crown-group (Gauthier et al.,
1989). A crown-group is a clade that includes the last common ancestor of two or
more extant taxa, and all its descendants. In this case, Tetrapoda was defined
as the clade that includes the last common ancestor of lissamphibians and
amniotes, and all its descendants." -- from the Tree of Life Website; the
specific URL is:

http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/terrestrial_vertebrates.html

-- JSW