Olive Warbler (Peucedramus taeniatus) - HBW 15, p. 665

Taxonomy: Sylvia taeniata du Bus de Gisignies, 1847, Mexico = San Cristóbal, Chiapas.
Species formerly known as P. olivaceus, but that name invalid, as preoccupied. Relationships uncertain and much disputed; seems to be an ancient lineage with no close relatives, although has recently been tentatively linked with the accentors (Prunellidae). In the past, genus often placed in New World warbler family (Parulidae), in which considered close to Dendroica, and sometimes subsumed in latter; other taxonomists considered it closer to Old World warblers (Sylviidae), on basis mainly of certain internal morphological traits. Recent genetic studies involving DNA-DNA hybridization indicate that placement in a family of its own (considered not particularly closely related to Parulidae) is probably the most appropriate treatment, pending further studies. Geographical variation predominantly clinal, individuals becoming smaller and brighter from N to S. Isolated population in NW Coahuila (N Mexico) presumed to belong with jaliscensis, but racial identity uncertain; further study required. Some uncertainty regarding correct type locality (see page 660). Proposed races georgei, described from S Mexico (R Molina, in S Oaxaca), and aurantiacus, described from SC Guatemala (Chilasco, in Baja Verapaz), are included within nominate. Five subspecies currently recognized.