RE: Classification: A Definition

[Mike Taylor <mike@indexdata.com>]

Christopher Taylor writes:
 > A significant proportion of currently recognised taxa (indeed,
 > probably even the _majority_ of currently recognised taxa when you
 > consider invertebrates, protists, etc.) are not directly based on
 > evolutionary relationships. We all hope and usually expect that
 > said taxa reflect evolutionary relationships, but this has not yet
 > been explicitly tested in far too many cases, and in far too many
 > cases it is unlikely to be tested in the easily foreseeable
 > future. In the meantime, it is very convenient to use a system of
 > nested groups reflecting overall similarity, especially if we
 > understand that these are yet to be tested. I personally work on
 > members of an invertebrate "infraorder" that contains over 500
 > species, of which probably less than twenty have been included in
 > any sort of phylogenetic analysis. To have this group reduced to a
 > list of _incertae sedis_ taxa would make things very difficult -
 > where would I start?

This is an excellent point, and not one I've seen raised before --
which is odd, given the huge proliferation of PhyloCode-is-bad
articles out there.

 > I personally would hate to see phylogeny made an obligatory part of
 > taxonomy. Firstly, because there are taxa out there that are
 > taxonomically distinguishable (due to possessing unique
 > characters), but may not be reliably placed in a phylogenetic
 > analysis at present (due to shortage of material or some such
 > reason).

I don't see how that is a problem, though.  I have just such an animal
in the works at the moment -- clearly new, very different from
anything that already has a name, yet not resolvable with any
confidence at all below the level Neosauropoda.  I'd call that
Neosauropoda incertae sedis; would you instead prefer to give it a
monogeneric family?  If so, to what end?

(Mind you, it does bring to four the number of neosauropod families
known from the Weal--hey!  Stop hitting me!)

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "Say what you like about the Church of England, it rarely
         declares fatwahs.  It rarely declares anything at all, in fact"
         -- Andrew Rilstone.