Phylogenetic relationships in the Rhyacophila tristis group based on the mtCOI barcode region and estimated by maximum likelihood, as implemented in IQ-TREE v.2.1.3 (Minh et al. 2020). Nodal support was calculated using the ultrafast bootstrap (UFboot) approximation (Hoang et al. 2017); nodes with UFboot values greater than 95% are considered well supported. Branches with support values of less than 70% were collapsed. Branch lengths are measured in nucleotide substitutions per site (see scale bar for reference). The branch leading to Rhyacophila was shortened (total branch length was 0.12 substitutions per site). Numbers in parentheses correspond to GenBank accession numbers. The holotype and the Corsican larvae are shaded.