taxonomy vs taxonomical

taxonomy is a noun but taxonomical is not a noun.

Word	Noun	Adjective	Verb	Adverb
taxonomy	Yes	No	No	No
taxonomical	No	Yes	No	No

taxonomy (noun)	taxonomical (noun)
practice of classifying plants and animals according to their presumed natural relationships
(biology) study of the general principles of scientific classification
a classification of organisms into groups based on similarities of structure or origin etc

taxonomy (adjective)	taxonomical (adjective)
	of or relating to taxonomy