Five new species of tree-frog discovered in Papua New Guinea!
Author: Nicholas Groenenberg
Did you know that there are more than 7,500 identified frog species worldwide? So it seems unbelievable that yet another frog species, in fact, five new ones, have been discovered. Scientists from Griffith University and both Queensland and South Australian Museums have discovered five new tree-frogs in Papua New Guinea. These frogs show characteristics that are rarely displayed by other species.
Due to its geographical isolation, Papua New Guinea holds arguably the most diverse collection of frog species in the world, with 530–540 recognised species, many of which are endemic to the island country (found nowhere else). This number is significantly greater than in other countries, such as Australia, which has only 250 species identified.
Figure Red-bellied Tree-frog, photo by Steven Richards 2023
The first of the five frogs discovered is the Red-bellied Tree-frog (Litoria haematogaster), which has only been found in a single location atop the Darai Plateau. In Greek, ‘haematogaster’ translates to ‘blood belly’. This frog is thought to possess a bright red belly to startle predators when jumping or it is flipped on its back (Richards et al., 2023; ABC News, 2023).
Figure Lisa’s Tree-frog, photo by Steven Richards 2023
Second, is Lisa’s Tree-frog (Litoria lisae) was named after the wife of the study’s lead researcher, Dr Steven Richards. This species is only found in limestone karst habitat in the lower forests of the Gobe and Iagifu Ridges in the Kikori River basin, southern Papua New Guinea. Although the karst region is particularly dry, it appears that these frogs can be heard calling from sinkholes that persist with wet pools suitable as refugia for their tadpoles. Unfortunately, the challenging terrain of these sinkholes makes collecting these frogs difficult as the karstic landscape is laced with traps, spikes, and very hard terrain to traverse (Richards et al., 2023; ABC News, 2023).
Figure Darai Plateau Tree-frog, photo by Steven Richards 2023
Third, the Darai Plateau Tree-frog (Litoria daraiesnsis), like the Red-bellied Tree-frog, is only known to be found in a single location, which is how it gained its name. This tree frog has translucent hands and feet and is identified as a climbing frog with strong limbs (Richards et al., 2023; ABC News, 2023).
Figure Slender Spotted Tree-rog
Fourth, the Slender Spotted Tree-frog (Litoria gracilis) was observed in numerous areas scattered throughout the Papua New Guinea highlands, and so was among the most common and widespread of the new species. This makes its late discovery, well into the 21st century, even more surprising. Due to the significantly wet environment, these frogs live in, they have adopted a particularly abnormal reproductive method. Unlike most other species, this tree-frog uses a glue-like substance to attach the eggs to leaves above a body of water. This is instead of the traditional method of laying its eggs directly in water, adopted by most frog species worldwide (Richards et al., 2023; ABC News, 2023).
Figure Crater Mountain Treehole-frog, photo by Steven Richards 2023
Finally, the Crater Mountain Treehole-frog (Litoria naispela), like the Slender Spotted Tree-frog, attaches its eggs to tree trunks. When the tadpoles are ready, they will be washed into the tree hollows below. The name ‘naispela’ translates in the Creole Papua New Guinea language of Tok Pisin to ‘attractive’ or ‘beautiful’. However, in the early stages of its life, the frog has a distinct bird-poo-like appearance, which is unique among the world’s frogs, and is an astounding evolutionary adaptation to camouflaging itself from predation. The bird-poo mimicry is thought to be used to avoid predation when they are young, as the tree hollows they hatch from are popular bird-drinking spots. As the young frogs age, they change to a beautiful green colouration with white markings (Richards et al., 2023; ABC News, 2023).
Figure Crater Mountain Treehole-frog, photo by Steven Richards 2023
Given that a wide range of predators inhabit water; from birds and reptiles to less obvious predators such as diving beetle larvae and spiders, a possible explanation for the unusual reproductive methods of these frogs is to prevent predation. As a result of their cunning evolutionary tactics, the frogs have a higher chance of survival.
Studying and discovering new species can have multiple benefits for our planet. First, it can aid in understanding the living world around us and the variety of life forms that exist on this planet. Second, discovering new species can assist us in identifying areas with high biodiversity and endemism, which can lead to the creation of protected areas that are important in safeguarding these hotspots for conservation. Third, it can help involve Indigenous Peoples in conservation efforts by integrating traditional naming conventions into the new species and raising the profile of Indigenous languages. Fourth, establishing new species as ‘flagships’ for conservation can be an approach that involves the public in conservation efforts and helps carry the message for other “less charismatic” species that occupy the same habitats and therefore enjoy the benefits of that habitat being protected. Finally, researching new species can help us determine potential solutions to human problems, such as new forms of medicine, biomimicry in technology and design, and the emerging carbon market, all of which may contribute to preserving these species’ habitats and advancing our global sustainable economy.
Bibliography
Richards, S. J., Donnellan, S. C., and Oliver, P. M. (2023). Five new species of the pelodryadid genus Litoria (Tschudi) from the southern versant of Papua New Guinea’s Central Cordillera, with observations on the diversification of reproductive strategies in Melanesian treefrogs. Zootaxa, 5263(2), 151–190. https://doi.org/10.11646/zootaxa.5263.2.1
ABC News. (2023, April 13). Frog that looks like poo, sticks eggs to trees, among new species from PNG. ABC News. https://www.abc.net.au/news/science/2023-04-14/bird-poo-frog-five-new-species-papua-new-guinea-png/102207720
