The Southern Races of the White-Throated Spadebill (Platyrinchus mystaceus)

Abstract

I recently compared specimens of the White-throated Spadebill (Platyrinchus mystaceus, a tyrant flycatcher ranging from Mexico to Argentina) that I collected in Corrientes and Misiones, Argentina, during September and October 1967, with material of that species in The American Museum of Natural History collected by W. H. Partridge and by the Emil Kaempfer expedition. It was immediately evident that northeastern Argentine specimens differ from specimens of P.m. from eastern Brazil. Further comparisons and study of all relevant material (125 specimens) of this species in the A.M.N.H. revealed that P.m. mystaceus actually comprises two groups of populations. One of these occupies a range extending eastward and southward from southern }Viato Grosso, central and southern and Misiones and Corrientes, Argentina, to central Paran/t, western Santa Catarina, and eastern Rio Grande do Sul, Brazil. The other group occurs in Brazil from Maranh•to south to eastern Paran/t, and from the Atlantic Coast west probably to eastern }Viato Grosso. These populations of P. mysta'ceus are apparently in contact with P.m. bifasciatus of central }Viato Grosso, but there is a hiatus (in Amazonia) between them and the northern and western South American races of this species (Meyer de Schauensee, 1966: 359). The type locality of P.m. Vieillot is Paraguay, and its basis is a description from Azara supplied by Azara's friend Noseda, who lived in San Ignacio (Guazfi), southern Paraguay. Following the suggestion of Cory and Hellmayr (1927: 265), I designate Noseda's place of residence, San Ignacio (San Ignacio Dept.), as the type locality of the nominate race. The earliest available name for the eastern (Brazilian; see the range outlined above) group of populations is Platyrhyncho• cancromus Temminck (see Temminck and Laugier, 1838, plate 12; Cory and Hellmayr, 1927: 266), which was published in September 1820, as part of Livraison (plate 12, fig. 2; see Sherborn, 1898: 485-488). I have tried to locate the type of P. cancro•nus (Temminck) at museums in Paris (thanks to Jean Dorst and C. Voisin) and Leiden (thanks to. G. F. Mees). The latter (in litt.) located a mounted specimen of P. which appears to be the specimen figured in pl. col. 12 fig. 2 (of Temminck and Laugier, loc. cit.). Its label reads only: Platyrhynchus