Single gene points to separate bird species
Posted: March 16, 2015 at 9:45 am
1 hour ago by Geoff Vivian A Scarlet robin (Petroica boodang). Credit: Roger Smith
The scarlet robin (Petroica boodang) may be classified into separate eastern and western Australian species following thousands of years of evolution separated by natural geographical barriers including the Nullarbor Plain.
WA Museum geneticist Gaynor Dolman, who studied a dozen accepted species, says the robin is one of several southern Australian birds whose populations have been separated by natural barriers for so long they have become distinct species.
These include the chestnut quail-thrush (Cinclosoma castanotum), white-naped honeyeater (Melithreptus lunatus), New Holland honeyeater (Phylidonyris novaehollandiae) and white-eared honeyeater (Nesoptilotis leucotis).
Dr Dolman says several natural geographical barriers appear to have prevented populations from mixing at different times.
She says the most permanent and significant of these is the "Eyrean Barrier" consisting of the Flinders Ranges and the salty Lake Eyre Basin in South Australia, which has kept some populations separate for at least 600,000 years.
She attributes the oldest species divergence, perhaps 1.5 million years ago, to this barrier.
Dr Dolman says the Nullarbor Plain had been in the landscape for a long time and potentially affects the birds.
"But they also might be able to get past the Nullarbor at different periods where there's more drainage in the system or the shoreline is further back," she says
Dr Dolman the Nullarbor may have led to a later species divergence about 275,000 years ago in some cases, and there may have been a more recent divergence that is yet to be confirmed.
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Single gene points to separate bird species