A new species has been discovered halfway across the world with the help of a University professor.
Biological sciences assistant professor Jake Esselstyn and his research team discovered a new species of rat in Sulawesi Island, Indonesia, which made the International Institute for Species Exploration Top 10 New Species List.
The slender root rat, or Gracilimus radix, is a small mouse that looks like a mouse and shrew rat mix.
Esselstyn, who is also the LSU Museum of Natural Science curator of mammals, and his team discovered the rat in Indonesia during their field work there within the past year. The team camps at fairly remote, wet places and live out of a tent for several weeks, Esselstyn said. Since 2010, Esselstyn has traveled to Indonesia, Malaysia and the Philippines researching and discovering new animals.
Discovering new species is a norm for Esselstyn. He and his team find new mammals nearly every expedition they embark on in Southeast Asia. On Sulawesi Island, they discovered the species Bunomys torajae in 2011, Paucidentomys vermidax in 2012 and Waiomys mamasae in 2016 from the same site, he said.
To find all of these new species, they spend time trapping mammals using a variety of techniques. The root rat was trapped by a fall trap, which is a buried bucket in the ground surrounded by a fence pathway that lures the prey into the trap.
“We build a little fence that sort of funnels the animals towards the buckets and they run along the inside of the fence,” Esselstyn said. “They follow the fence until they fall in the bucket, if we’re lucky.”
The root rat is different from other species of rats because it is an omnivore, Esselstyn said, while most of its closest relatives are carnivores. The rat has a different anatomy compared to other wild rodents and belongs to its own genus, according to the Journal of Mammalogy.
“When diets change over evolutionary time, they tend to change from omnivorous to carnivorous in rats, but it doesn’t usually go back — except in this one case,” Esselstyn said in a news release.
The research doesn’t end there, though. Esselstyn plans to use this particular rat to learn more about the biogeography of rats in Southeast Asia, and how rats are spread out or arranged in an ecosystem. He and his research team also plan to study the rats’ molecular and physical traits.
While the morphology, or the physical traits, of the root rat were different from anything Esselstyn had seen before, with its different body size, fur and teeth, Esselstyn said the rat’s diet is what set it apart from all of the other species discovered.
“[We’re interested in] how many times they colonize a particular island [and] how many species evolved as a result of those colonization events that happened several million years ago,” Esselstyn said. “We’re interested in molecular evolution processes and we’re interested in how morphological diversity arises in these rats.”
