Cytochrome c oxidase subunit I barcode species delineation methods imply critically underestimated diversity in 'common' Hermeuptychia butterflies (Lepidoptera: Nymphalidae: Satyrinae)

DNA 'barcoding' has contributed greatly to resolving species limits in rapidly diverging tropical insect groups. Here, we explored species diversity in the widespread, cryptic Neotropical butterfly genus Hermeuptychia by generating 601 new sequences of the cytochrome c oxidase I (COI) barcode, tripling available information. Our dataset focused in particular on Ecuador, a biogeographically pivotal country, with additional sequences from Brazil, Costa Rica, French Guiana, Guatemala, Mexico, Panama and Peru. We examined the performance of two phylogeny-based approaches for objectively delineating species, Generalized Mixed Yule Coalescent (GMYC) and Poisson Tree Processes (PTP), as well as a clustering-based approach, Automatic Barcode Gap Discovery (ABGD), on the combined dataset, including our data and 302 published sequences. In general, GMYC and PTP tended to cluster or split likely species as assessed from morphology, depending on model settings, whereas ABGD was less sensitive and produced a more plausible classification. Numerous sequences formed well-supported clades, putative species, that were unrepresented in previously published datasets. The average diversity across all methods was 45 species, in contrast to the 11 species recognized in the current taxonomy. The resulting COI dataset, in combination with ongoing genomic and morphological research, should significantly clarify our understanding of Hermeuptychia species diversity.

Automated summary

The study utilized DNA barcoding to explore species diversity in the Neotropical butterfly genus Hermeuptychia, revealing 45 potential species compared to the current taxonomy's recognition of 11 species. Comparative analysis showed that the Automatic Barcode Gap Discovery (ABGD) method was more reliable and plausible in delineating species boundaries.