A team of biologists has discovered two new species of frogs in New Guinea, one of which breaks the record for the world’s tiniest known vertebrate.

The team led by Christopher Austin, associate professor of biological sciences at Louisiana State University (LSU) and curator of herpetology at LSU’s Museum of Natural Science, made the discovery during a three-month long expedition to New Guinea.

The study, published in the PLoS One journal, describes frog species Paedophryne amanuensis, averaging only 7.7 mm in size (less than one-third of an inch), and slightly larger Paedophryne swiftorum, measuring 8.5 mm.

“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.”

Paedophryne amanuensis is named after Amau, a village in Central Province, Papua New Guinea.

This frog ousts fish species Paedocypris progenetica, averaging more than 8 mm, from the record for the world’s tiniest known vertebrate. It also ousts recently discovered frogs Paedophryne dekot and Paedophryne verrucosa from the record for the world’s smallest known frog.

Paedophryne swiftorum is named after the Swift family, in recognition of their generous contributions that enabled the establishment of the Kamiali Biological Station, Papua New Guinea, where the species was collected.

“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,” Austin added.

“The ecosystems these extremely small frogs occupy are very similar, primarily inhabiting leaf litter on the floor of tropical rainforest environments. 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,” concluded Austin.