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Re: thoughts on which nodes to name



> > Am writing an essay 'What is a
> > Reptile' for a tutor and it is giving me a slight headache.
>
> Short answer for this well beaten topic.....
> The reason Reptilia is retained is because it has historical priority
(being
> named in the archaic days of yore) and phylogenetic definitional priority
> (being defined as all descendants of testudines, squamates, Sphenodon and
> crocodilians, and their common ancestor; Gauthier et al. 1988).  The
> vernacular definition of reptile includes those taxa listed in the
> definition, the definition just assures it is monophyletic.

The Phylocode doesn't like such big additions to traditionally paraphyletic
groups to make them monophyletic. I really think Huxley's 19th century terms
Theropsida and Sauropsida should be used for those amniotes which are closer
to mammals or birds, respectively, which was the author's intent AFAIK, at
least that of a certain Goodrich, 1916.

> So it's not
> defined the way it is to be a group of organisms containing every
> non-synapsid except mesosaurs.

Mesosaurs, BTW, are not synapsids/theropsids*, they are real anapsids, close
to Bolosauridae, Procolophonidae, Pareiasauridae etc. and probably turtles.
When turtles don't belong there the clade should be called Proganosauria.
Just forgot the ref, I think somewhere in Palaeontologia Africana in 1999.

* Not that I argued for correcting all misnomers, but Synapsida refers to
the presence of a temporal opening... mesosaurs have none, and even though
they don't belong in that clade, something without temporal fenestrae must
have, at the very base. The diadectomorphs have once been suggested to be
such animals.

> Everything in Reptilia has always been
> viewed as a reptile for at least the last century,

For less than the latter half or so of the last century. In 1956 , if I
interpret the ref correctly, von Huene "refrained from a separation of
the --> amphibians and partitioned the lower tetrapods into the
subclasses: --> Urodelidia (urodeles) and --> Eutetrapoda, this again into
the superorders: --> Batrachomorpha, --> Reptiliomorpha, -->
Sauromorpha, --> Theromorpha." And then it mentions Kuhn-Schnyder who in
1963 thought that reptiles were a grade and polyphyletic -- such things
happen without cladistic analysis :-)
        Von Huene included (same ref) the following orders in his
Reptiliomorpha: 1. Anthracosauria, 2. Seymouriamorpha, 3. Microsauria, 4.
Diadectomorpha, 5. Procolophonia, 6. Pareiasauria, 7. Captorhinidia, 8.
Testudinata. His Batrachomorpha seems to have consisted of Stegocephalia
(aaargh) and Anura. Sauromorpha was a grouping of the orders 1. Eosuchia, 2.
Thecodontia, 3. Saurischia, 4. Ornithischia, 5. Crocodilia, 6. Pterosauria,
7. Rhynchocephalia, 8. Squamata. Theromorpha, a particular goodie, was the
grab-bag for 1. Mesosauria, 2. Pelycosauria, 3. Therapsida, 4. Placodontia,
5. Sauropterygia, 6. Protorosauria and (sometimes?) 7. Ichthyosauria.

Ulrich Lehmann: Paläontologisches Wörterbuch [Paleontological dictionary],
3rd edition, Ferdinand Enke 1985; especially the entry "Reptilien"
(Don't know if the 4th edition still has all that.)

> Including birds

and excluding all synapsids/theropsids

> in the Reptilia is surely less confusing than scrapping the term

Sure?

> when reptile is so intrenched in both the public and scientific
> communities.

It is not entrenched in the public community. Go ask someone about the
difference between reptiles and amphibians, or about whether salamanders are
reptiles or amphibians. Most people I've heard risking a statement thought
that salamanders were lizards (and made the impression that they'd have
believed me anything because I looked like I knew about such ivory-tower
vocabulary). Yes, people do usually learn it in school, but if so, then
very, very shortly -- I've never been examined about that, IIRC -- , and by
far most forget it immediately.