Conservation news

New species of tree frog from Ecuador has a mysterious claw

  • A team of biologists surveying a remote and largely unexplored part of the Andes in Ecuador have described a new species of tree frog that’s dark brown in color, with bright orange flecks dotting its body.
  • The researchers have named the tree frog Hyloscirtus hillisi, after David Hillis, a U.S. evolutionary biologist known for his work on the Hyloscirtus genus of tree frogs.
  • While the researchers don’t have an estimate of the frog’s population, they think its numbers are likely low.
  • The species’ small habitat also lies near a large-scale mining operation, putting the frog at immediate risk of extinction.

A team of biologists surveying remote parts of the Cordillera del Cóndor (Condor mountain range) in Ecuador’s eastern Andes have described a species of tree frog that’s new to science.

The dark brown frog with bright orange flecks dotting its body wasn’t easy to find. The researchers had to walk along very steep terrain in the largely unexplored Cordillera del Cóndor to reach the slopes of a tabletop limestone mountain where they encountered the frog. Moreover, the frogs tended to blend with the environment, making them hard to spot.

“Between sweat and exhaustion, we arrived to the tabletop where we found a dwarf forest. The rivers had blackwater and the frogs were sitting along them, on branches of brown shrubs similar in color to the frogs’ own,” Alex Achig, one of the field biologists who was part of the expedition, said in a statement.

The tree frog has a mysterious claw-like structure at the base of its thumb, the researchers say in a new study published in ZooKeys. The purpose of this protruding structure, also known as prepollex, is unclear, but the researchers think the frogs might use it as a weapon to defend against predators or competing males. The gladiator tree frog (Hypsiboas rosenbergi), for example, uses its spiny prepollex to fight off other males while protecting its nest.

The new species has a claw at the base of the thumb. Image by Gustavo Pazmiño/BIOWEB Ecuador.

The researchers have named the newly discovered tree frog Hyloscirtus hillisi, after David Hillis, a U.S. evolutionary biologist from the University of Texas in Austin. Hillis, an amphibian expert, is known for his work on Hyloscirtus tree frogs, including the discovery of three Hyloscirtus species in the Ecuadoran Andes during the 1980s. The genus Hyloscirtus includes 37 other species of tree frogs distributed across Costa Rica and the Andes of Bolivia, Colombia, Ecuador, Peru and Venezuela.

The researchers were able to spot H. hillisi individuals at just two nearby sites on the tabletop mountain, at elevations between 1,991 and 2,134 meters (6,500 and 7,000 feet). While they don’t have an estimate of the frog’s population, they think its numbers are likely low.

“In 2017, at the site where the tadpoles and juveniles were found, five hours of nocturnal search by five experienced herpetologists yielded no adults,” the authors write in the paper. “At the site where the adults were found, ten hours of nocturnal search, for two nights, by two experienced herpetologists, yielded two adults and one subadult.”

The species’ small habitat also lies near a large-scale mining operation, the researchers say, which puts the frog at immediate risk of extinction.

“Because of its small known distribution and nearby habitat destruction and mining activities, we suggest to assign H. hillisi to the Critically Endangered category,” the authors write.

An adult of the recently discovered species Hyloscirtus hillisi. Image by Gustavo Pazmiño/BIOWEB Ecuador.

Citation:

Ron, S. R., Caminer, M. A., Varela-Jaramillo, A., & Almeida-Reinoso, D. (2018). A new treefrog from Cordillera del Cóndor with comments on the biogeographic affinity between Cordillera del Cóndor and the Guianan Tepuis (Anura, Hylidae, Hyloscirtus). ZooKeys, (809), 97.