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'Cryptic Species' May Unlock Philippines' Bird Diversity

Thanks to striking physical similarities between species, the Philippines may harbor more unique bird species than previously thought, according to a new study. The finding, the researchers said, could mean big changes for conservation in the region.

David Lohman of the City College of New York and his team of fellow researchers from four different countries have suggested that the Philippines already known as a biodiversity hotspot may have many more unique species of birds than originally realized.

Many of the animal species found in the Philippines are endemic to the nation, which is made up of more than 7,100 islands. To date, 64 percent of its land mammal species and 77 percent of its amphibians are found nowhere else. However, only 31 percent of its bird species are considered to exist only in the Philippines.

But sometimes what may look like two individuals of the same species are actually members of completely different species. These so-called cryptic species cannot be distinguished using shape, size and color of an organism and can often only be told apart by genetics.

"Our research was motivated by the need to estimate the prevalence of cryptic species in Southeast Asia and to identify particular areas where cryptic species are most likely to be found," Lohman said. "We studied genetic diversity in birds, butterflies, flies, frogs and fish."

Lohman studied seven species of small, perching birds that are found in the Philippines and elsewhere in Southeast Asia. Through a series of genetic tests designed to reconstruct evolutionary histories and identify genetic differences, he found that samples from Philippines populations of the birds were always distinct from samples from other parts of Southeast Asia.

Currently, there is not enough information to determine if these unique birds may be a different species, but they have distinct genetic lineages from the birds they resemble elsewhere.

"The geological history of Southeast Asia is complex. The ancestors of these birds seem to have dispersed to the archipelago 1.5 to 4.6 million years ago, but there appears to have been no genetic exchange since then," Lohman told OurAmazingPlanet. "This is most likely because changes in the geography of the area have not been conducive to dispersal to the Philippines from elsewhere for a very long time. This isolation has fostered differentiation and, potentially, speciation."

The Philippines have already lost 75 percent of their forest, and unless steps are taken, new birds like the ones found by Lohman and his colleagues may never be discovered, the scientists warned.

"In no other place on this planet is conservation more crucial than in the Philippines," Lohman said. "While the species we studied are not in danger of extinction, other undiscovered species might be."

OurAmazingPlanet Staff