Cladistic species definitions can lead to under-representation of biodiversity from adaptive radiations

Abstract

Many species are paraphyletic, but current taxonomic practices often do not recognize this, and attempts are made to apply a monophyletic species concept. While allowing the recognition of ecomorphologically equivalent, or even phenotypically indistinguishable allopatric, taxa as species, this often leads to combining distinctive local forms (such as cave-adapted populations) or even whole adaptive radiations (often in lakes) with widespread paraphyletic species to force species monophyly. It is suggested that this has negative consequences for our documentation and understanding of biodiversity, as well as for conservation, through issues such as lack of IUCN red-listing.