Calibrating phylogenetic species formation in a threatened insect using DNA from historical specimens.

Museum specimens from the late 19th and early 20th centuries were surveyed for the single nucleotide polymorphism identified previously and used to diagnose populations of the federally threatened Northeastern Beach Tiger Beetle Cicindela d. dorsalis (Coleoptera: Carabidae). Widespread polymorphism was revealed throughout the historical range of this species, suggesting a relatively recent anthropogenic character fixation event associated with the extinction and fragmentation of populations. Implications for the phylogenetic species criterion and for the reintroduction of individuals to formerly occupied sites are discussed.