THE HISTORIC Biak na Bato National Park in Bulacan is now the site of a significant discovery.
It is where a team of researchers—including College of Science professor Mae Lowe Diesmos and husband Arvin of the Philippine National Museum—discovered a new frog species belonging to the Platymantis genus. With the group were Rafe Brown, Cameron Siler, and Charles Linkem of the Kansan University in the United States. The new find was christened Platymantis biak, in recognition of the natural reserve.
‘Limestone’ frog
In 2009, Diesmos and her team started a study on amphibians and reptiles at the park. After field surveys of reptile and amphibians in the area, they concluded that the find was indeed a new frog species.
Not alone in its genus, the Platymantis biak, which is barely the size of an adult thumb, adds to the growing number of Platymantis frogs, which now stand at 29.
Platymantis biak are usually spotted in their microhabitats—limestone crevices or gaps found in caves in Biak na Bato National Park. Frogs thrive in moist places like these, where temperature is naturally low.
They are classified as karst-habitat specialists or organisms that live in soluble bedrocks like limestones and dolomites.
The study had long been planned after Diesmos’ husband, Arvin, was convinced that a new species was awaiting official discovery going by the unique mating calls or croaks at the national park in Bulacan.
The researchers even compared members of the Platymantis genus from this new species to ascertain the new discovery. The bases of comparison were morphology, advertisement or mating call, and molecular structure.
The scientists will first study the morphology of the frog by measuring the eyes, fingers and toe discs, and by looking for other differences in physical characteristics.
Like the usual Platymantis, the Platymantis biak also has moderately expanded fingers and toe discs. But it differs from other genuses because it confines itself to terrestrial habitats. The Platymantis genus is sensitive to changes in temperature.
“Frogs stay in limestone because amphibians adapt to cool temperature,” Diesmos said.
Second is the “advertisement calling.” The mating of these species can be done first by “advertisement call” or mating call. When the male frog “calls,” members of its species can easily recognize it, but others would not.
Advertisement calls are measured through peaks of sound waves in the frog’s croaks, which will determine if the species is old or new.
Despite the diversity of the Platymantis genus in the country, the biaks are genetically and reproductively isolated to their own species.
“They consider it as one already so they cannot mate with the other species,” Diesmos said.
Lastly, they consider the deoxyribonucleic acid (DNA) or molecular structure of the species.
Herpetologists are researchers who study amphibians and reptiles. They prefer to get DNA samples from the liver because it has more DNA structures compared to any other part of the body.
Diesmos and her colleagues checked the base pare of the DNA and found significant differences.
“You can say that the difference in the DNA makeup is significant,” Diesmos said.
Though Diesmos acknowledged that the discovery might not generate a major public interest, she and her colleagues still pursued the research.
“Admittedly, frogs are not charismatic and cute. I’m talking from the common people’s views,” she said. “But if you look at it from our perspective, as scientists, frogs play a very important role in the environmental niche.”
If one is to go back to their biology lessons, frogs are part of the food chain that once it is removed, the chain will be destroyed. For example, the snake that feeds on the frog may die if the frog is removed from the food chain. Likewise, the disruption of the food chain will hamper the ecosystem.
The Platymantis biak research was published last May 2010 in Zootaxa, an international journal for taxonomists which reviews studies from reputable institutions and universities.
