Probably sister to the group formed by P. guianensis. Recent suggestions that birds in E Panama and NW Colombia possibly represent an undescribed race now questioned in light of additional specimen material. Monotypic.
C & E Panama, W Colombia and NW Ecuador.
Atwood, J. & Lerman, S. (2019). Slate-throated Gnatcatcher (Polioptila schistaceigula). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/58992 on 25 April 2019).