Hunting For Rare Toad, Scientists Discover A Voiceless Species Of Frog

The frog’s eyes are smaller relative to its head, compared to the proportion in other spiny-throated reed frogs.

Researchers have discovered a previously unknown species of frog, which is unique in itself because it is voiceless. The team has described the Ukaguru spiny-throated reed frog (Hyperolius ukaguruensis) in the journal PLOS One.

In 2019, an international team of scientists began a search for a toad, believed extinct, in the Ukaguru Mountains of Tanzania. Instead, they discovered a previously unknown species of frog, which is unique in itself because it is voiceless.

The team has described the Ukaguru spiny-throated reed frog (Hyperolius ukaguruensis) in the journal PLOS One.

Almost all frog species croak or sing to communicate with other frogs. The Ukaguru spiny-throated reed frog is among the few species that do not do so. “Spiny throated” reed frogs get their name from tiny spines on the male’s throat, which prevents them from vocalising. There are very few such species around the world.

Most frogs croak in order to enable other members of their species to recognise them. Since the new species cannot do so, the team believes it might use some other means of communication, according to team leader Lucinda Lawson, a conservation biologist at the University of Cincinnati.

“We think they may use the spine as something like Braille for species recognition. Without a call, they need some other way to recognise each other,” a press release from the university quoted Lawson as saying.

The search by Lawson’s team was originally for Churamiti maridadi, a beautiful tree toad. Seen only twice in the wild, both times in Ukaguru, the frog is feared extinct.

The team scoured the area by day and by night, looking under logs and in tree holes, and setting up buried traps. They did not find the tree toad, but instead came across the new species of reed frog, which is locally abundant.

 “Immediately it was clear that it was a spiny-throated reed frog. But this one was a golden, greenish brown instead of the green colour found in the other species,” Lawson was quoted as saying.

Subsequent scientific analysis confirmed that the frog was a previously undocumented species, belonging to the genus Hyperolius but distinct from its other members.

The frog’s eyes are smaller relative to its head, compared to the proportion in other spiny-throated reed frogs.

The researchers believe there could be conservation concerns around the newly discovered frog. Tanzania’s population is growing, putting its mountain forest habitats under threat from humans. This is particularly true of amphibians. They absorb chemicals through their skin, so any changes in water acidity or introduction of toxins leave them more vulnerable than many other animals.