Least-inclusive taxonomic unit: a new taxonomic concept for biology

Phylogenetic taxonomy has been introduced as a replacement for the Linnaean system. It differs from traditional nomenclature in defining taxon names w ith reference to phylogenetic trees and in not employing ranks for supraspe cific taxa. However, 'species' are currently kept distinct. Within a system of phylogenetic taxonomy we believe that taxon names should refer to monop hyletic groups only and that species should not be recognized as taxa. To d istinguish the smallest identified taxa, we here introduce the least-inclus ive taxonomic unit (LITU), which are differentiated from more inclusive tax a by initial lower-case letters. LITUs imply nothing absolute about inclusi veness, only that subdivisions are not presently recognized.