Using DNA sequences for 402 of the 452 species of the world's "babblers," an international team from China, Sweden, Denmark, Switzerland and the USA have analysed the evolutionary relationships among these species. Many of these species have not previously been studied using genetic methods, and this is by far the most comprehensive analysis of this group of birds to date.
This study identified seven main groups of babblers, which were estimated to have started to differentiate c. 18–20 million years ago, during the period known as the Miocene. The authors suggest that all seven main groups should be treated as different families. One of these groups was described as a new family, Alcippeidae, which comprises a single genus (Alcippe) of rather small, mostly grey and brown forest birds from southern Asia. One large family (Sylviidae) was divided into two families (a smaller Sylviidae and a reinstated Paradoxornithidae) , because these were so anciently diverged (19.5 million years ago).
Multiple other, previously unrecognised relationships were revealed, including some that suggested the presence of several currently unrecognised "cryptic species." One species, the White-collared Yuhina, was found to be so distinctive that it was proposed to be placed in a new genus, Parayuhina.
The babblers are a large group of passerine birds, comprising 452 species. Most of these live in the southern parts of Asia, but many also occur in Africa. Only a few species are found in Europe, including common birds such as the Blackcap, Garden Warbler and Lesser Whitethroat. A single species, the Wrentit, lives in North America.
The babblers inhabit forests and various types of scrubland, from sea level to above the tree limit. In general, they are very secretive, hiding in dense vegetation. The diversity in size (c. 6–155 g), shape and plumage is enormous. Some species are very dull and non-descript, whereas others have amazing colour patterns. Many species are renowned for their beautiful complex songs, which are often given in perfectly synchronized duets between males and females.
This study will form a firm basis for future analyses of the ecology, evolution and conservation of babblers.
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More information: Tianlong Cai et al. Near-complete phylogeny and taxonomic revision of the world's babblers (Aves: Passeriformes), Molecular Phylogenetics and Evolution (2018). DOI: 10.1016/j.ympev.2018.10.010
Alice Cibois et al. Comprehensive phylogeny of the laughingthrushes and allies (Aves, Leiothrichidae) and a proposal for a revised taxonomy, Zoologica Scripta (2018). DOI: 10.1111/zsc.12296
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