Saturday, 8 March 2014 00:00
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By Ella Davies
BBC Nature: A unique family of birds containing just one species has been discovered by researchers.
Scientists investigating families within the Passerida group of perching birds identified 10 separate branches in their tree of life.
The analysis also revealed that the spotted wren-babbler sat on its own branch and was not related to either wrens or wren-babblers. Experts recommend the distinctive bird should now be referred to as Elachura. The discovery is published in the Royal Society journal Biology Letters.
This single species is the only living representative of one of the earliest off-shoots within the largest group of [perching birds], which comprises [around] 36% of the world’s 10,500 bird species, said Prof Per Alstrom from the Swedish University of Agricultural Sciences, Uppsala, who undertook the study alongside researchers from the Chinese Academy of Sciences, Beijing.
Elachura formosa is a small perching bird – or passerine – that is found from the eastern Himalayas to southeast China.
Prof. Alstrom describes it as extremely secretive and difficult to observe, as it usually hides in very dense tangled undergrowth in the subtropical mountain forests.
However, during the breeding season, when the males sing their characteristic, high-pitched song, which doesn’t resemble any other continental Asian bird song, it can sometimes be seen sitting on a branch inside a bush.
He suggests the bird had previously been overlooked because it looks strikingly similar to wrens and wren-babblers. This similarity is apparently either due to pure chance or to convergent evolution, which may result in similar appearances in unrelated species that live in similar environments - some wren-babblers can be neighbours to the Elachura, Prof Alstrom explained.
The biologists made their discovery by analysing the molecular differences in the DNA of the birds to understand what they had inherited, and thus reveal their evolutionary heritage. This method has been widely used in recent years and is responsible for a number of surprising discoveries including the revelation that a peregrine falcon is more closely related to a bullfinch than a sparrowhawk.
Molecular analyses have been instrumental in resolving the relationships among birds, and have revealed multiple totally unexpected relationships, such as between flamingos and grebes, between falcons, parrots and passerines, and between larks and the bearded tit, explained Prof. Alstrom.
It is possible that more such cases will be discovered in the future, as more and more species are being analysed. However, I doubt that there are many – if any – such unique species as the Elachura left to be identified.
