Ungarbled version

Doug Yanega dyanega at POP.UCR.EDU
Tue Oct 16 22:55:43 CDT 2001


I'll keep this brief: I think the more technical we get, the less
interest people will have. Nonetheless, I still don't think that
Richard's system allows for certain complexities of classifications.
Take his example:

>  > ASSERTION table
>>  ID      Citation                Name    Parent
>>  ----------------------------------------------
>>  1       OrigDescr, 1999          b       A
>>  2       X et al. 2000            b       C
>  > 3       Y et al. 2000            b       D

But go *beyond* that level of the hierarchy. It is not uncommon - and
anyone who works routinely with classifications knows this - for a
single author's definitive work to cover several ranks
simultaneously, such that their circumscriptions are interdependent.
Occasionally, then, when you have competing classifications, two
authors may use the exact same named ranks, but define (circumscribe)
each of them differently. If so, the format you give above will not
preserve those relationships: it only relates child to parent, not
child to *grandparent*, etc.

In other words, if author X says

species A is in genus B of subfamily C of family D
species J is in genus K of subfamily C of family D

and author Y says

species A is in genus B of subfamily C (same name but entirely
different circumscription) of family E
species J is in genus K of subfamily L of family D

the assertion table would be

name   parent
A       B
B       C
C       D
C       E
J       K
K       C
K       L
L       D

and the "assertion table" will not be able to reconstruct the fact
that one should ONLY classify species A as belonging to family E *if*
one defines C the way author Y does. Further, it isn't fair to list
both D and E as parents to C, because in neither author's
classification can species J be considered a member of family E (that
is, not all children of C are grandchildren of E). Your designation
of the "preferred" links certainly would help, but what happens when
there are thrid and fourth and fifth authors' opinions that also use
the same names in different ways? What would happen is you'd lose
track of which authors' schemes grouped things which ways. This kind
of thing does actually happen. I still do feel that you can't
reconstruct a single author's phylogeny by giving simple lists of
parent-child linkages, and a phylogeny is - in certain respects - a
single specific hypothesis that one *would* want to represent
faithfully.

Peace,
--

Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California - Riverside, Riverside, CA 92521
phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
            http://entmuseum9.ucr.edu/staff/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82




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