Description of Crypsiphona tasmanica sp nov (Lepidoptera: Geometridae: Geometrinae), with notes on limitations in using DNA barcodes for delimiting species

External morphological differences were found between Tasmanian and mainland Australian specimens of what was previously considered a single species, the Redlined Geometrid, Crypsiphona ocultaria (Donovan). Examination of genitalia showed constant differences, suggesting that Tasmanian and mainland Australian populations represent distinct species. This hypothesis was tested using DNA sequences from the mitochondrial cytochrome oxidase subunit I (COI) gene and nuclear elongation factor 1-alpha (EF-1 alpha) gene. Tasmanian Crypsiphona Meyrick populations were found to represent a distinct species, described here as C. tasmanica sp. nov. The results show that a phylogeny-based approach allows the delimitation of C. ocultaria (Donovan) and C. tasmanica sp. nov., but distance-based delimitation is problematic due to substantial overlap in intra- and interspecific genetic distances. Using nucleotide data in character-based species delimitations might be possible for discriminating between C. ocultaria and C. tasmanica, but our current knowledge does not allow the assignment of characters required for this purpose.