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LSU Professor Discovers World's Tiniest Vertebrate

Tiny frog called Paedophryne amauensis averages around 7 millimeters in size; fits in center of U.S. dime


Watch video of Chris Austin describing the discovery of Paedophryne amanuensis, the world's tiniest vertebrate.

LSU’s Chris Austin recently discovered two new species of frogs in New Guinea, one of which is now the world’s tiniest known vertebrate, averaging only 7.7 millimeters in size – less than one-third of an inch. It ousts Paedocypris progenetica, an Indonesian fish averaging more than 8 millimeters, from the record. Austin, leading a team of scientists from the United States including LSU graduate student Eric Rittmeyer, made the discovery during a three-month long expedition to the island of New Guinea, the world’s largest and tallest tropical island.

 “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.

The research, which will be published in the Public Library of Science One journal, or PLoS, on Jan. 11, includes a second species of diminutive frog newly named Paedophryne swiftorum that is only slightly larger than Paedophryne amauensis, averaging only about 8.5 millimeters in body size.

Austin’s work, supported by the National Science Foundation, highlights an interesting trend among the discovery of extremely small vertebrates.


Chris Austin in the herpetology collection at LSU's Museum of Natural Science.
Eddy Perez/University Relations

“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 (75 feet) and the smallest previously being the small Indonesian fish averaging around 8 millimeters, 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.”

For more information about Austin’s research lab, visit http://www.museum.lsu.edu/Austin/lab.html.

About the LSU Museum of Science:

The mission of the LSU Museum of Natural Science is the acquisition, preparation and study of research collections by museum faculty, staff and students to generate knowledge of regional and global biodiversity, geological history and human history and prehistory for the benefit of the people of the state, the nation and the world. The vast storehouse of scientific information held within LSUMNS collections helps researchers understand the historical and contemporary processes that have shaped the world’s biological diversity. With nearly 3 million specimens and growing, the LSUMNS collections are an invaluable resource that will yield countless important discoveries for generations to come, and researchers at the museum are responsible for the discovery of nearly 60 species new to science, ranging from invertebrate fossils to reptiles, fish, birds and even mammals. For more information about the MNS, visit www.lsu.edu/museum.