Taxon sampling, character sampling and systematics: how gradist presuppositions created additional ganglia in gastropod euthyneuran taxa (original) (raw)

Haszprunar's "clado-evolutionary" classification of the Gastropoda - a critique

Malacologia, 1990

A recent classification of the Gastropoda (Haszprunar, 1988b), based on a "clado-evolutionary" methodology (Haszprunar, 1986), is analyzed and criticized. Although his publication (1988b) provides a wealth of new anatomical information and a valuable summary of recent research efforts in gastropod systematics, the methodology employed by Haszprunar, combining elements of cladistic data analysis and intuitive evolutionary taxonomy, is considered to be inferior to standard cladistic approaches. The presentation of the data is incomplete and inconsistent. The analysis is not repeatable, Haszprunar's hypothesis of phylogenetic relationships therefore not testable. So-called "cladistic" or "sequential" classifications as provided for comparative purposes are improperly or inconsistently derived. Rather than preserving traditional nomenclature as claimed, his "cladoevolutionary" approach leads to the unnecessary naming of monophyletic and paraphyletic groupings.