Yellow-margined Flatbill

The yellow-margined flatbill or Zimmer's flatbill (Tolmomyias assimilis) is a species of bird in the tyrant flycatcher family Tyrannidae. It is found in every mainland South American country except Argentina, Chile, Paraguay, and Uruguay. == Taxonomy and systematics == The yellow-margined flatbill has a complicated taxonomic history. It was originally described as Rhynchocyclus assimilis. In the early twentieth century it was treated as a subspecies of the yellow-olive flatbill (now T. sulphurescens) but was separated by most authors starting in about 1940. As of 2025 it has eight subspecies. However, what is now the yellow-winged flatbill (T. flavotectus) was previously a ninth subspecies. It was separated starting in 2016 but the process continued until 2024. Confusingly, for a time T. flavotectus was called the yellow-margined flatbill. The eight subspecies of the yellow-margined flatbill are: T. a. neglectus Zimmer, JT, 1939 T. a. examinatus (Chubb, C, 1920) T. a. obscuriceps Zimmer, JT, 1939 T. a. clarus Zimmer, JT, 1939 T. a. assimilis (Pelzeln, 1868) T. a. sucunduri Whitney, Schunck, MA Rêgo & Silveira, 2013 T. a. paraensis Zimmer, JT, 1939 T. a. calamae Zimmer, JT, 1939 The taxonomy of the yellow-margined flatbill is still in flux. Subspecies T. a. sucunduri was…