[Taxacom] Sampling/ Pseudoreplication in Morphometric Taxonomy

[Doug Yanega]

Treating morphology in a statistical manner can run afoul of what amount 
to type I and type II errors, in that sometimes people group two taxa as 
if they were one (so the documented variation is between rather than 
within taxa), or decide that the amount of variation they see represents 
two taxa (so they then treat the variants separately) when it is 
actually one taxon involved. Since taxonomy is fundamentally 
typological, it is perhaps best to make sure that the description of the 
holotype for a taxon is firmly and accurately established first, and 
only then should one start expanding the circumscription to include 
variation. It can be quite frustrating trying to discriminate two taxa 
when the original taxon descriptions give a range of values that could 
possibly apply to both. The more populations one is sampling from, the 
more of a concern this all becomes, especially in the era of molecular 
systematics, where cryptic taxa are routinely being discovered.

Peace,

-- 
Doug Yanega      Dept. of Entomology       Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314     skype: dyanega
phone: (951) 827-4315 (disclaimer: opinions are mine, not UCR's)
              https://faculty.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82