Atronanus

The forest swallow (Atronanus fuliginosus) is a little-known species of swallow in the family Hirundinidae, found in Cameroon, Republic of the Congo, Equatorial Guinea, Gabon, and Nigeria.

The species was previously placed in the genus Petrochelidon, within the 'mud-nester' clade of swallows, yet its plumage, morphology, and nesting behavior did not align well with those of other major swallow lineages. As a consequence, and also employing molecular phylogenetic approaches, De Silva et al. (2018) placed this species in the swallow phylogenetic tree, firmly within the 'mud nester' clade, but outside of the clade corresponding to Petrochelidon. This outcome led De Silva et al. (2018) to document and describe formally a distinct, generic-level lineage of swallow endemic to the Lower Guinean forest region of central Africa.