𝗦𝗶𝘅 𝗡𝗲𝘄 𝗦𝗽𝗲𝗰𝗶𝗲𝘀 𝗼𝗳 𝗧𝗶𝗻𝘆 𝗠𝗲𝘅𝗶𝗰𝗮𝗻 𝗙𝗿𝗼𝗴𝘀

Researchers from the University of Cambridge, University of Texas and the Natural History Museum in London recently described six new species of tiny flesh-bellied frogs from Mexico. The new species are 𝐶𝑟𝑎𝑢𝑔𝑎𝑠𝑡𝑜𝑟 𝑏𝑖𝑡𝑜𝑛𝑖𝑢𝑚, 𝐶. 𝑐𝑎𝑛𝑑𝑒𝑙𝑎𝑟𝑖𝑒𝑛𝑠𝑖𝑠, 𝐶. 𝑐𝑢𝑒𝑦𝑎𝑡𝑙, 𝐶. 𝑝𝑜𝑙𝑎𝑐𝑙𝑎𝑣𝑢𝑠, 𝐶. 𝑝𝑜𝑟𝑡𝑖𝑙𝑙𝑜𝑒𝑛𝑠𝑖𝑠 𝑎𝑛𝑑 𝐶. 𝑟𝑢𝑏𝑖𝑛𝑢𝑠. Adults grow to a snout-vent length of 13 to 18 mm. 𝐶𝑟𝑎𝑢𝑔𝑎𝑠𝑡𝑜𝑟 𝑐𝑎𝑛𝑑𝑒𝑙𝑎𝑟𝑖𝑒𝑛𝑠𝑖𝑠, which grows to only 13 mm, is now the smallest frog species known from Mexico. This small size is not too distant from the smallest frog species in the world – 𝑃𝑎𝑒𝑑𝑜𝑝ℎ𝑟𝑦𝑛𝑒 𝑎𝑚𝑎𝑛𝑢𝑒𝑛𝑠𝑖𝑠 from Papua New Guinea, which is slightly less than 8 mm in length.

These frogs are unusual in that they do not experience a tadpole developmental stage like most frogs, growing directly from eggs into tiny frogs! They live in leaf litter and are likely preyed on by just about all carnivorous vertebrates and invertebrates that they encounter.

But how have these new species gone undetected for so long? Surely people have seen them around? They probably have! However, their tiny size and drab colouration may have suggested to others that they were merely juveniles of other, closely-related, species from the area. The team of researchers investigating this group of frogs used a combination of DNA sequencing and CT-scanning of the skeleton to demonstrate that they were sufficiently different from one another, and the other six known species in the genus, to be described as separate species.

Although the discovery of the new species is very exciting, all six frogs have been classified as either Endangered or Data Deficient, which is of concern. However, the researchers involved in the study think that their success in identifying the new species may indicate that there are more species of this genus in Mexico just waiting to be described.

𝗧𝗲𝘅𝘁 𝗯𝘆 Cora Stobie (Department of Animal and Plant Systematics).

𝗧𝗵𝗶𝘀 𝗶𝘀 𝘁𝗵𝗲 𝗼𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗿𝗲𝘀𝗲𝗮𝗿𝗰𝗵 𝗮𝗿𝘁𝗶𝗰𝗹𝗲:

Tom J.M. Jameson, Jeffrey W. Streicher, Luigi Manuelli, Jason J. Head, Eric N. Smith. Miniaturization in Direct-Developing Frogs from Mexico with the Description of Six New Species. Herpetological Monographs, 2022; 36 (1) DOI: 10.1655/0733-1347-36.1.1

𝗣𝗵𝗼𝘁𝗼: 𝐶𝑟𝑎𝑢𝑔𝑎𝑠𝑡𝑜𝑟 𝑐𝑢𝑒𝑦𝑎𝑡𝑙 sitting on a Mexican coin. The species name is a Nahuatl word for ‘frog’. Image © University of Cambridge and Jeffrey W. Streicher, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) from https://www.cam.ac.uk/stories/tiny-frogs.