FIOCRUZ | Cryptic taxa in the morphospecies Bichromomyia flaviscutellata uncovered by expanded geographic sampling and COI DNA barcodes

We expanded sampling to 12 Brazilian municipalities across the Amazon, Cerrado, and Atlantic Forest biomes, generating 62 new mitochondrial COI sequences and integrating them with publicly available data.Phylogenetic reconstruction and multiple species delimitation methods consistently recovered two deeply divergent and well-supported mitochondrial lineages within B. flaviscutellata.

Lineage PS1 is distributed across the Amazon, Cerrado, and western Atlantic Forest, whereas PS2 is restricted to the coastal Atlantic Forest. Additional substructure was detected within both lineages. Genetic distances were high between PS1 and PS2 but low within lineages, while other taxa (e.g., B. bicolor and B. olmeca) each formed a single cohesive cluster.The observed mitochondrial divergence suggests long-term isolation; however, species boundaries require confirmation using multilocus nuclear data.