Delimitation of species
Our operational criterion of species delimitation is to determine phenotypically and genotypically distinct clusters (Sites and Marshall, 2004). To this end we employed step-wise evaluation of the mitochondrial and morphological variation (‘reciprocal corroboration’) to recognize distinct species by using four criteria: (1) distinct species form clades, (2) these clades are well differentiated from other such clades, (3) the morphology of species differs in at least one feature that is unlikely to be polymorphic or under environmental control, (4) no intermediate morphs exist. This procedure is considered a conservative approach in species delimitation. As it requires consistent differentiation in morphological and mitochondrial markers, it would not necessarily recognize morphologically cryptic species or phylogenetically young species sharing ancestral genetic polymorphisms.
For clarity, the following molecular and anatomical comparisons are presented with reference to the newly introduced taxon names. However, the underlying taxon delimitations resulted from the combined assessment of the molecular and anatomical differentiation and were not foregone conclusions preceding these analyses.