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Re: Synapsids are NOT reptiles!



As usual, Tom beat me, but I think my information is complementary
rather than duplicative so I'm submitting this anyway:

Dinogeorge@aol.com gets (IMHO) persnickety by writing:

> The fact that the common fish-tetrapod ancestor would undoubtedly be
> called and classified as a fish by any rational observer had the
> tetrapods never evolved makes no difference to cladistic
> taxonomy. The dogma of monophyletic taxa produces some pretty
> contorted neologisms.

Since George was an observer (if not a participant) in the relevant
discussions which occurred on s.b.p about a month ago, he should be
well aware that the word "fish" has no formal taxonomic standing
according to anybody (*I'd* like to see a formal reference to the
taxon "fish" if anyone knows of one used during the last 50 years...).
In the colloquial sense that the word "fish" is frequently used (both 
within and outside of scienctific meetings), LN Jeff is correct in
claiming that we are descended from fish.

For the taxonomic answers to most of LN Jeff's questions, I think we
need go no farther than the archives of this list.  On November 10,
1995, Adam Yates <zooamy@zoo.latrobe.edu.au> wrote:

  Amphibians are now defined as all tetrapods more closely related to
  modern amphibians (a monophyletic assemblage known as the
  Lissamphibia)than to amniotes (Synapsids + Reptiles).  There are of
  course primitive members of the lineage leading to amniotes that
  have the primitive method of aquatic reproduction, they are not
  however members of the Amphibia sensu stricto. True amphibians
  include colosteids, temnospondyls, lissamphibians, probaly
  microsaurs and possibly Nectrideans

Further back (July 14, 1994), David Schwimmer (who's e-mail address
changed and I'm too lazy to look up the new one right now, but in any
case he's NOT Ross Geller) wrote:

    First, I'm by no means a rabid cladist.  In fact, by pure
  cladistic logic, allowing no paraphyly, we're crossopterygian fish.

Although others wouldn't likely phrase it that way, I believe that
phylogenetic taxonomists do consider us _Crossopterygia_ as David said
(even if David doesn't!).  Most of the "fish" alive today are
classified as _Actinopterygia_, a sister group to _Crossopterygia_,
but there are some _Crossopterygian_ "fish" still extant.

-- 
Mickey Rowe     (rowe@lepomis.psych.upenn.edu)