‘Guardian' creatures — that carry their young on their backs — are new species

Miami Herald

24-06-2025

In the rainforests of Malaysia, a group of 'guardian' creatures carry their young on their backs.
The animals are about 1.5 inches long, but the males' bare backs can hold tadpoles carefully positioned on the skin as they are moved between shallow puddles.
The guardian frogs of Borneo have long been broken up into two distinct species: Limnonectes palavanensis, the smooth guardian frog, and Limnonectes finchi, the rough guardian frog.
Now, as researchers studied these frogs across the Malaysian islands, they noticed that frogs previously thought to belong to the smooth species had different calls, according to a study published June 23 in the peer-reviewed journal Zootaxa.
The smooth guardian frogs aren't one species at all — they're seven different species.
Limnonectes palavanensis was first identified on the island of Palawan in the Phillipines in 1894 and was later found in Borneo in 1897, according to the study.
The animals were collected by British civil servant and naturalist Alfred Hart Everett, but it wasn't until the mid-20th century that researchers first observed 'tadpole-transport' by the species, researchers said.
After researchers noticed discrepancies in the calls of different smooth guardian frogs, they set out to test their theory that there may be more than one species present on Borneo by collecting frogs by hand at night and photographing them in the field, according to the study.
The original L. palavanensis is described as being small in size with a 'moderately sturdy' body that is widest toward the head and tapers back toward the groin.
Their skin is like that of untanned leather, researchers said, and small bumps are scattered on the upper eyelid and back.
The species is brown with blackish bands, and the sides of the body have white in them, according to the study.
Researchers gave the species a new common name: the Palawan guardian frog.
Genetic testing confirmed the presence of seven other closely related species that had been misidentified as the Palawan guardian frog, according to the study.
Limnonectes gunungensis, L. kinabaluensis, L. nephophilus, L. oreibates, L. phylax, L. sarawakensis and L. suboliferus were described by researchers.
L. gunungensis, or the mountain guardian frog, is found in the 'moist leaf litter' near small streams in the mountains of Sarawak, Malaysia, according to the study.
The Kinabalu guardian frog, or L. kinabaluensis, was 'collected under a log, another one on a rock, others on the ground and under leaves in leaf litter,' researchers said. The frog was also observed releasing tadpoles from its back into a puddle in Kinabalu National Park.
L. nephophilus earns its common name, the cloud-forest guardian frog, from its home in the montane cloud forests of Gunung Mulu and Gunung Murud, according to the study. A tadpole of the species was found in a small pool between rocks in a dried stream bed.
The Penrissen guardian frog, L. oreibates, makes slow chirping calls and derives its name from the ancient Greek word for 'mountaineer,' according to the study. Another male of this species was found along an intermittent stream with tadpoles on his back.
L. phylax kept the common name of the smooth guardian frog because males were found guarding their eggs before reaching the tadpole stage, researchers said. Once the eggs hatch, the tadpoles hitch a ride on their father to a close body of water.
The Sarawak guardian frog, L. sarawakensis, was found in Lambir Hills National Park and has a long rising trill of a call, according to the study. Tadpoles were discovered in 'pools of small intermittent streams, in low shallow buttress tank, in a water-filled hole in a log, in small isolated rain pools on forest floor and in a shallow puddle with silky bottom and scattered leaves,' researchers said.
The last new species, L. suboliferus, was found in a place called 'frog pond' in Kubah National Park, according to the study. The western guardian frog earns its name from the Latin words meaning 'the one that carries the offspring.'
The research team includes J. Maximilian Dehling, Dario N. Neokleous, Indraneil Das, T. Ulmar Grafe, Pui Yong Min and Stefan T. Hertwig.