Re: crocodylians, amphibians ... (was Sarcosuchus)

["David Marjanovic" <david.marjanovic@gmx.at>]

> > The same
> > goes for the even more short-sided redefinition of the term Amphibia
> > (especially the most restricted redefinition to the crown group
> > lissamphibians).
>
> I would agree I don't like Amphibia restricted to crown-group frog &
> salamander relatives.  However, I have no problem with Amphibia being all
> taxa closer to _Rana_ than to _Homo_, with Lissamphibia the crown group
> amphibians.

I agree, and what's more important, the latter definition is strongly
suggested on the Tree of Life page. I like it actually. Lissamphibia has
always been used for the crown group, though often between quotation marks,
by everyone who thought it was holophyletic to the exclusion of Paleozoic
"temnospondyls", "lepospondyls" and so on.

> One way to point out that _Acanthostega_ and _Ichthyostega_ are not
> amphibians or tetrapods in any modern sense is to point out that if you
were
> a Devonian fisherman and hooked one of these guys on a line, when you
hauled
> it up you could open its gillflaps to show the nice (pink?) gills, just
like
> a trout or salmon.

Just for the record -- while *Acanthostega* did have internal gills,
*Ichthyostega* didn't, probably because it lived on probably oxygen-poor
river/pond floors. But there is a distinction of that sort: Both were unable
to put their hindlegs ventrally, and therefore unable to stand and walk
outside of water.

> The only real difference between it and animals that
> would unquestionably be called fish (like lungfish)

Just for the record, lungfish were long considered amphibians (*Lepidosiren*
= SA lungfish, *Siren* = a urodele), and had Owen found the choanae of his
lungfish specimen, he wouldn't have changed that :-)

> that you would be able
> to see is that its fins would end in a flared-out mitten with six or seven
> or eight prongs.

Frogfish fins look amazingly like that.