- 1 species in southern Asia
- DR personal total: 0 species (0%), 0 photo'd
past 10 years have witnessed a surge in taxonomic changes in Asian
birds, partly as a result of molecular analyses," wrote Per
Alström and coauthors in Biology Letters in 2014. One of
the most surprising was that White-bellied "Yuhina," a common bird
throughout much of tropical Asia, and well-ensconsed within the
Babblers, was actually related to Vireos in the New World (Cibois 2003,
Alström et al. 2006); see the Erpornis page. Now something even more shocking has been discovered.
et al. (2014) were interested in the evolution of Asian babblers. The
international team amassed a huge DNA sequence dataset for the
Passerida, which represents about 60% of global bird species. They
found the Passerida was composed of ten clades [evolutionary lineages],
nine of which were expected. But on a single "bare branch" at the base
of the evolutionary tree was something totally unexpected — a tiny
"wren-babbler," traditionally known as Spotted Wren-Babbler "Spelaeornis formosus," which had recently been moved to its own genus (Elachura) because of distinctive morphology and vocalizations (Collar & Robson 2007).
Here (left, in an amazing shot by Roon Bhuyan) is Elachura, now described by Alström et al. (2014) as the only extant member of the ancient family Elachuridae.
Elachura is, to quote a blog by "grrlscientist" in The Guardian
in April 2014, a "little brown bird that is so shy that it's heard more
often than seen as it goes about its business in dense moist forests
throughout the mountains of tropical and subtropical Asia." It is
usually located by its distinctive vocalization, and it does hide in
the undergrowth, where it is a local resident within its range. This
map (right) is from Alström et al. (2014) and shows the range of
Elachura in red: eastern Himalayas extending down mountain chains into
Burma and Vietnam, and an isolated range in the mountains of southeast
China. The three black (and named) dots on the map where the locations
of specimens analyzed by Alström et al. (2014).
"grrlscientist" blog interviewed Per Alström about the discovery
of this unique little bird. He said that he doubted "that we'll find
another species that belongs in the same family. So the Elachura is
likely to be a true loner." It managed to avoid detection as a unique
family for so many years because of the "wonders of convergent
evolution," which permit unrelated species to evolve to resemble each
other because they occupy similar niches.
seeing one in the field, Alström himself had seen it in both India
and China, but added "It's extremely difficult to watch, as it inhabits
dense undergrowth, often in little gullies on very steep mountain
slopes." As to finding one: "All of the ones that I've seen I've first
noticed by their distinctive song."
were once a half-dozen or so other genera that were called
wren-babblers but it is truly remarkable that when genetic analysis was
undertaken, two of them were not babblers at all. Elachura proved to be
this ancient lineages, and the genus Pnoepyga, sometimes called the
"pygmy wren-babblers," were also not babblers and were elevated to the
Pnoepygidae, the Cupwings. Will there be
more surprises? It seems unlikely. The DNA evidence published so far
has found that the remaining wren-babblers with the family Timaliidae,
but that there they divide yet again: genus Spelaeornis is within the subfamily Timaliinae while the remaining genera termed wren-babblers (e.g., Rimator, Ptiolcichla, Kenopia, Napothera) are now assigned to this subfamily Pellorneinae.
Several major world checklists (e.g., Clements, IOC) currently elevate
what I recognize as three subfamilies of Babblers to three Family-level
groupings. In that scenario, the "old" wren-babblers have proven to
belong to four (!!) different families.
Photos: The Elachura Elachura formosa was photographed in Arunachal Pradesh, India.
Photo © Roon Bhuyan, as credited, and used with permission; all rights reserved.
I am grateful to Murray Lord, Tony Paliser, and Abidur Rahman for help
in obtaining permission to use this very nice photograph.
Bibliographic note: There is no "family book" on this new family, but a good
introduction to the genus, with photos, is in Collar & Robson
P., P.G.P. Ericson, U. Olsson, and P. Sundberg. 2006. Phylogeny and
classification of the avian superfamily Sylvioidea. Molecular
Phylogenetics & Evolution 38: 381-397.
P., D.M. Hooper, Y. Liu, U. Olsson, D. Mohan, M. Gelang, L.M. Hung, J.
Zhao, F. Lei, and T.D. Price. 2014. Discovery of a relict lineage and
monotypic family of passerine birds. Biol. Letters 10 (3)
Cibois, A. 2003. Mitochondrial DNA phylogeny of babblers (Timaliidae). Auk 120: 35-54.
Collar, N. J. and C. Robson. 2007. Family Timaliidae (Babblers) pp. 70–291 in Handbook of the Birds of the World J. (del Hoyo, A. Elliott, & D.A. Christie, eds.). Vol. 12. Lynx Edicions, Barcelona.