RE: On the subject of mysterious absences...The Answer

[Mike Taylor <mike@indexdata.com>]

Tim Williams writes:
 > > "Thecodontia" is a useful term for all those archosauriform taxa
 > > that do not belong to any of the "major" archosauriform groups
 > > (Saurischia, Ornithischia, Crocodylia, Pterosauria).
 > 
 > So you would lump together _Euparkeria_, proterosuchians,
 > erythrosuchians, phytosaurs, aetosaurs, rauisuchians,
 > non-crocodylian crocodylomorphs, basal ornithodirans
 > ("lagosuchians", "silesaurs"), and even basal dinosaurs (if
 > _Eoraptor_, _Herrerasaurus &c lie outside both Saurischia and
 > Ornithischia)...?

Yes ... when and only when that was the group of animals that I wanted
to talk about, i.e. the "ancestral stock".  It's pointless to pretend
that we don't need to talk about these animals -- the very existence
of the term "thecodont" shows that it's needed.

I surely don't need to tell you that I'm not recommending that this
name be used _instead_ of Archosauromorpha or any of the other names
that we also find useful.

Bottom line: we all need to get over our bizarre fixation that clades
are only taxa than can be named.  It's completely arbitrary -- on a
par with saying that only taxon names that begin with a vowel are
acceptable.  The point of taxonomy is utility.

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "Everyone knows that debugging is twice as hard at writing
         a program in the first place.  So if you're as clever as you
         can be be when you write it, how will you ever debug it?" --
         Kernighan & Pike, _The Elements of Programming Style_