(informal) A taxon that exists only to classify organisms that do not fit anywhere else, being either paraphyletic or polyphyletic and therefore not considered valid under modern rules of taxonomy.

(paleontology) A taxon that falsely appears to persist until, or reappear at, a time in the fossil record later than the taxon's actual point of extinction, due to fossils of organisms belonging to the taxon having been eroded from their original strata and redeposited in the source sediments for younger strata.

Of, or relating to taxonomy.

Of or pertaining to taxonomy.

(biology) An increase in the number of species that is not caused by new discoveries, but by changes in the classification of existing organisms.

(taxonomy) A coherent system of taxonomic judgements on circumscription and placement of the considered taxa. A taxonomic system is restricted to a large but limited part of the living world.

(taxonomy) Someone whose profession is taxonomy, or who performs taxonomy at a professional level.

plural of taxonomy

An internal node in phylogenetic analysis; an inferred ancestral organism.

A terminal node in phylogenetic analysis; an organism.