Tropical Kingbird (Tyrannus melancholicus) - HBW 9, p. 419

Taxonomy: Tyrannus melancholicus Vieillot, 1819, Paraguay.
Closest relatives of genus may be Empidonomus and Tyrannopsis; recent molecular-sequence data indicate present genus is monophyletic and sister-group to clade that includes Empidonomus and Griseotyrannus; two main clades within genus, loosely corresponding to “tropical species assemblage” and combination of “W” & “E” species groups of earlier authors, but with some exceptions. Present species formerly treated as conspecific with T. couchii owing to limited hybridization in Mexico (S Veracruz, Atlantic slope of N Oaxaca), and possibly intergrades with it, but differs significantly in voice. Furthermore, recent molecular data indicate that these two are not each other’s closest relatives, but that present species is sister to T. dominicensis, with both nested within an expanded “tropical assemblage” as sister-group to an unresolved clade consisting of T. albogularis, T. couchii and T. savana. In addition, a possible hybrid “T. apolites” between present species and Empidonomus varius described from Rio de Janeiro area of SE Brazil. Geographical variation over the species’ enormous range very inadequately known, and current taxonomy potentially erroneous; race satrapa apparently intergrades with nominate. Three subspecies currently recognized.