Newly discovered frog is world’s tiniest vertebrate

January 2012: The world's tiniest known vertebrate is one of two new species of frog to have been discovered in New Guinea.

TINY: The frog sits on a US dime, about the size of a 5p piece

Averaging just 7.7mm in size, the frog ousts Paedocypris progenetica, an Indonesian fish averaging just over 8mm from the record.

LSU's Chris Austin made the discovery during a three-month long expedition to the island of New Guinea, the world's largest and tallest tropical island.

High-pitched, insect-like mating call
‘It was particularly difficult to locate Paedophryne amauensis due to its diminutive size and the males' high-pitched insect-like mating call,' said Austin. ‘But it's a great find. New Guinea is a hotspot of biodiversity, and everything new we discover there adds another layer to our overall understanding of how biodiversity is generated and maintained.'

Austin, curator of herpetology at LSU's Museum of Natural Science and associate professor of biological sciences, is no stranger to discovering new species, having described numerous species previously unknown to science, including frogs, lizards and parasites.

These most recent species descriptions highlight an interesting trend among the discovery of extremely small vertebrates. The research was supported by the National Science Foundation.

Little is understood about extreme body size – large or small
‘The size limit of vertebrates, or creatures with backbones, is of considerable interest to biologists because little is understood about the functional constraints that come with extreme body size, whether large or small,' said Austin.

With more than 60,000 vertebrates currently known to man, the largest being the blue whale with an average size of more than 25 meters and the smallest previously being the tiny small Indonesian fish there was originally some thought that extreme size in vertebrates might be associated with aquatic species, as perhaps the buoyancy offers support and facilitates the development of extremism.

However, both new species of frogs Austin described are terrestrial, suggesting that living in water is not necessary for small body size.

‘The ecosystems these extremely small frogs occupy are very similar, primarily inhabiting leaf litter on the floor of tropical rainforest environments,' said Austin. ‘We now believe that these creatures aren't just biological oddities, but instead represent a previously undocumented ecological guild - they occupy a habitat niche that no other vertebrate does.'