American warblers unrelated to Old World namesakes
Parulidae—New World or wood-warblers—holds 120 small, often brilliant passerines confined to the Americas and unrelated to Old World or Australian warblers. Diversity peaks in northern Central America, likely the homeland from which migrants pushed north in interglacials and still return each winter.
Linnaeus tagged the northern parula as Parus americanus in 1758, as if it were a tit; later genus tweaks to Parulus and Parula gave the family its name. Alexander Wetmore’s group formally introduced Parulidae in 1947 with Parula as type; that genus is now sunk into Setophaga.
Most live in trees, but some, such as the ovenbird, forage largely on the ground. Two genera, Myioborus and Basileuterus, appear to have colonised South America. The family was long thought to be sister to a group containing the yellow-breasted chat, the wrenthrush, two Cuban warblers and the 109 species of blackbirds and orioles, though newer studies rearrange that picture.
A 2010 molecular study found that the species fell into major clades that ignored the traditional genera, forcing a wholesale reshuffle. One large clade included the 29 species then in Dendroica, four species of Parula, one Wilsonia and the single-species genera Catharopeza and Setophaga; all but Catharopeza were merged into an expanded Setophaga, a name coined by Swainson in 1827. The old Basileuterus split in two, with 18 species moved to the revived genus Myiothlypis, first named by Cabanis in 1850.
Six genera disappeared in the process: Dendroica, Ergaticus, Euthlypis, Parula, Wilsonia and Phaeothlypis, while the whitestarts of Myioborus came through unchanged. The family now holds 120 species in 18 genera. Several birds once counted as wood-warblers have moved elsewhere: the olive warbler and the yellow-breasted chat now have families of their own, three Granatellus species went to the cardinals, and two Hispaniolan species and two Cuban Teretistris warblers also left for separate families.
Source: New World warbler
