Biology, School of Science

Discovering a new species would be a thrill for any scientist. Imagine discovering 14 as part of just one study.

An international team of researchers, including Thomas Giarla, Ph.D., associate professor of biology at Siena, recently discovered 14 new species of shrews, the largest number of new mammals described in any scientific paper since 1931. 

The team spent 10 years taking inventory of shrews living on the Indonesian island of Sulawesi. Their findings are detailed in the recently published paper, “Fourteen New, Endemic Species of Shrew (Genus Crocidura) from Sulawesi Reveal a Spectacular Island Radiation” in a new issue of the Bulletin of the American Museum of Natural History. (Original study link here.) Their results have been picked up by The New Scientist, ABC News, Science Daily, Los Angeles Times, and the Associated Press.

Members of the research team examined an extensive collection of genetic and morphological data from new specimens they collected on Sulawesi between 2010 and 2018, combined with old specimens collected in 1916. Giarla was stateside performing the lab analysis. The team’s original hypothesis was that they might identify seven separate species of shrews on the island. Instead, they found 21 – two thirds of which were previously undiscovered.

“There is still a lot to learn about this world, and new tools are always being developed to help us conduct our research,” said Giarla. 

The group examined a total of nearly 1,400 specimens. The known diversity of shrews on Sulawesi is now three times more than is known from any other island.

Shrews are a diverse group of mammals—461 species have been identified so far—and they have a nearly global distribution. These small insectivorous animals are closer relatives to hedgehogs and moles than to any other mammals. Giarla built an evolutionary tree for the shrews based on analysis of their DNA. He and his colleagues then carefully examined hundreds of specimens for subtle anatomical traits that could be used to corroborate the genetic data.

How can entirely new species go undetected well into the 21st century? Sulawesi – the 11th largest island in the world – is heavily populated in the flat lowlands, but the shrews’ habitat is now mostly restricted to mountainous regions that are difficult to access. 

Giarla explained that one of the most obvious applications for these discoveries is in conservation. 

“Indonesia is a rapidly-growing nation, and with that comes increased use of natural resources,” he said. “Forests are being bulldozed, and plantations are being developed, which disrupts the ecosystems. Researching and identifying species – this basic taxonomy – helps inform the entire field of evolutionary biology as well as conservation efforts. Sulawesi has an absurd level of biodiversity, and understanding what life is there and how it evolved helps us preserve it.”

This is the second article of Giarla’s that has received national attention: in 2020, he was the lead author of a new study in the Zoological Journal of the Linnean Society, which verified the close cousins of an extinct semi-aquatic African mouse, including two species new to science. News about that research was picked up by Smithsonian, New Scientist, The Independent and Gizmodo

Giarla’s work is inspiring his students, including Peter Kirkpatrick ’22.

“Dr. Giarla is an amazing professor who makes his classes a lot of fun while also demonstrating a great knowledge of ecology and evolutionary biology,” said Kirkpatrick. “In ecology, we got to learn and read about the newest research on all sorts of interesting topics, from climate change to how pandemics spread to all sorts of interesting animals, including small mammals and shrews, with very unique and interesting biological adaptations. Dr. Giarla is able to transfer his excitement and love of ecology and evolutionary biology to his students through his teaching.”