A team of researchers, which has been studying a special bird species in the Amazon rainforest, has found that it was actually the first known hybrid bird species to be found in the region. The golden-crowned manakin, which was first discovered in Brazil in 1957, wasn't seen again until 2002.
A hybrid species is formed when two parental species mate to produce a hybrid population, which later stops being able to freely interbreed with the parental species. In case of the golden-crowned manakin, the two parental species were the snow-capped manakin and the Opal-crowned manakin.
The snow-capped manakin is characterised by its bright snowy-white crown feathers while the Opal-crowned manakin is known for its brilliant iridescent crown feathers. Their hybrid offspring, on the other hand, has much duller yellow crown feathers.
Formation of hybrid species is quite common among plants. But the same trait is extremely rare when it comes to vertebrates, according to John Weir, an associate professor at the University of Toronto, Scarborough (UTS), in Canada and senior author of the research.
As part of the study, which will be published in the journal Proceedings of the National Academy of Science (PNAS), the researchers sequenced a large portion of the golden-crowned manakin's genome, including 16,000 different genetic markers. The findings revealed that the hybrid species got about 20 percent of its genome from the snow-crowned manakin while about 80 percent came from the opal-crowned.
The researchers also used an electron microscope to have a closer look at the keratin structure of the crown feathers of all three bird species. Further analysis revealed that the golden-crowned manakin had a mix of keratin structures from both parental species.
Although the golden-crowned manakin likely had duller white or grey feathers early on in its existence, it eventually evolved yellow feathers as an alternative way to attract females.
In addition, the researchers also used a method called coalescent modelling to determine when the golden-crowned split off from its parental species. Researchers figured out that the two parental species originally mated around 180,000 years ago while they diverged from a common ancestor about 300,000 years ago.
"Most Amazon bird species diverged from their most recent relative around 1.5 to 4 million years ago, so these are all young birds by comparison" Weir said in a statement.
The golden-crowned manakin lives in an area about 200 square kilometres in the south-central Amazon. The area is largely separated by wide rivers from areas where snow-capped and opal-crowned manakins live.
According to researchers, the golden-crowned manakin owes its survival as a species on being geographically isolated from its parental species at some point during a past ice age.
"Without geographic isolation, it's very likely this would never have happened because you don't see the hybrids evolving as separate species in other areas where both parental species meet," Weir said.