The smallest frogs in the world: Paedophryne dekot (A) and (B), and P. verrucosa (C), and (D). Photo: Fred Kraus
Read out Two newly discovered frog species from the mountains of New Guinea grow to only eight to nine millimeters in size. This makes them the smallest known land vertebrates in the world. About half as long as a paperclip: Paedophryne dekot and Paedophryne verrucosa are the new mini-record holders among the known terrestrial vertebrates (tetrapods). ? Reduction is common among many frog genera around the world, ? Explorers discover Fred Kraus of the Bishop Museum in Honolulu, "but in New Guinea, there seem to be a particularly large number of genera with this phenomenon." Kraus discovered and described in 2010 two tiny frog species that grow up to 11.3 mm in size. But it was even smaller: The females of the newly discovered species Paedophryne dekot are 8.5? 9.0 mm long and in the species Paedophryne verrucosa 8.8? 9.3 mm. However, the absolute tiny creatures are apparently the males: in P. verrucosa they measure only 8.1-8.9 mm. The males of P. dekot have not yet found a researcher.

The species of the genus Paedophryne are all extremely small and live at the bottom of the forest between fallen leaves and moss, reports Kraus. Presumably, their small size is an adaptation to this habitat. The advantage is that they can access food resources in the leaf litter that their big relatives and food competitors can not access.

In addition to the size of the little things has another curious feature: They have only three functioning fingers on the front legs. Kraus suspects that the number of fingers has been reduced, while the animals have become smaller and smaller in the course of their evolution.

The frog females of the two new species apparently always lay only one or two eggs, reports Kraus. For comparison: The females of the European tree frog lay 200 to 1400 eggs. The small number of eggs is probably related to the mini-growth: The frogs may not be even smaller, otherwise they would not be able to carry enough oocytes in the body. The mini-amphibians are therefore probably at the lower limit arrived. display

Fred Kraus (Bishop Museum, Honolulu): Zoo Keys, doi: 10.3897 / zookeys.48.446 © wissenschaft.de - Maria Georgi

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