Re: Yet Another FAQ: phylum, order, family

[Mike Taylor <mike@tecc.co.uk>]

> Date: Fri, 10 Aug 2001 09:42:23 -0400
> From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
> 
> > The second and more far-reaching innovation was the introduction of
> > higher-level groupings than the genus. In Linnaeus's original system,
> > genuses
> 
> genera

Arrrgh!  I will go and disembowel myself honourably :-)

> > For example, the phylum Vertebrata, the vertebrates, is a part of
> > the animal kingdom.
> 
> Vertebrata is not a phylum; it is traditionally a subphylum within
> Chordata (along with Cephalochordata and Urochordata).

Noted (and fixed.)

> >       Order
> >       Parvorder
> >       Nanorder
> >       Hyporder
> >       Minorder
> >       Suborder
> >       Infraorder
> >       Gigafamily
> >       Megafamily
> >       Grandfamily
> >       Hyperfamily
> >       Superfamily
> >       Family
> 
> There are a large number of other ranks proposed above this.

I know -- I prefixed the list with ``[...] a hierarchy of thirteen
ranks just between order and family!''  This list is from Padian 1986
via DinoGeorge, so I'm assuming that so far as it's complete, it's
correct (although in the linked message, George points out that this
is just one interpretation.)

> I suggest checking out some classic works (like Matthew's
> classification of mammals) for stuff between the "class" and
> "subspecies".

Well, I don't really intend to worry too much about this since the
only reason I gave the list at all was to illustrate how silly it
was.  It's more a proof-of-concept illustration than anything.

> Additionally, the breakdown of units is different between
> traditional zoological and botanical subdivisions.

You mean that (for example) Megafamily might be more inclusive than
Gigafamily in the plant world?

> Incidentally, the suffixes added to various ranks within Animalia
> are not standardized for taxa above the family level.

What about -oidea for superfamilies?

> See many previous discussions in the DML archive: for example, how
> about
> http://www.cmnh.org/fun/dinosaur-archive/1997May/msg00421.html.

Thanks for this reference, I'll update the FAQ answer to include the
material about how suborder endings have varied in different fields.
Very illustrative.

> > This minimal
> > approach is particularly popular in the cladistics community, perhaps
> > in part because the trees generated by cladistic methods have far too
> > many nodes, and change far too often, to be amenable to labelling
> > with ranks.
> 
> Also from the recognition that there is no operational metric or system to
> determining if two taxa differ "at the family level" versus "at the
> superfamily level" or whatever;

Indeed.  I thought I'd made that point when I said ``and it _is_ a
matter of judgement rather than of fact; one man's parvorder is
another man's nonorder'' but I guess it bears re-emphasising.

> [...] and the problem of people recognizing equivalence of "rank"
> across taxa (i.e., is Ostreidae (oysters) somehow equivalent to
> Alligatoridae and these two to Archaeopterygidae?).

:-)

Many thanks for this swift and informative critique.

I am now going to make the unwarranted assumption that every part of
it that you _didn't_ criticise is ``sufficiently correct'' :-)

 _/|_    _______________________________________________________________
/o ) \/  Mike Taylor | <mike@miketaylor.org.uk> | www.miketaylor.org.uk
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