Scientists have discovered two new species of yellow-bellied bats, and say there could be more.
Though it’s surprising to find new species with such a prominent feature, scientists point out that it’s not so surprising that the creatures are bats. With more than 1,200 species, bats make up a whopping one-fifth of all mammal species.
But figuring out how all these bats are related to one another is no easy task, because in many cases their differences are subtle at best. And that’s why scientists from Chicago’s Field Museum only stumbled upon the two new species when they looked for small genetic differences in the course of creating an evolutionary family tree for Africa’s yellow bats. The details of their discovery are published Wednesday in the journal Frontiers in Ecology and Evolution.
The two new species belong to a group of bats known as Scotophilus. This group of bats, found across Africa and southern Asia, average around five inches in length and sport bright yellow fur on their bellies. Many species within Scotophilus live in urban environments, and some, such as the yellow house bat, often roost atop man-made structures.
More than half of these little bats were discovered within the last 15 years, and the relationships among them has been long been a source of confusion for biologists. For one thing, “they're fairly cryptic,” meaning that they’re hard to find in the wild, said Terry Demos, a postdoctoral fellow at Chicago’s Field Museum and lead author of the study. (Related: “6 Bat Myths Busted: Are They Really Blind?”)
Galapagos giant tortoises rest in a pool of mud in Volcan Alcedo’s crater on Isla Isabela. Many animals are nocturnal to avoid the heat of the day.
Spotting a Species
Eager to map the messy lineage of the Africa’s yellow bats, Demos and a team of researchers from Maasai Mara University and the National Museums of Kenya collected skin samples from just over 100 yellow bats in Kenya, and extracted DNA from each. By comparing the bats’ genetic profiles, Demos and his team were able to find differences among the species and determine where they would fall on an evolutionary family tree.
But when Demos started building the tree, he noticed two distinct lineages previously unknown to science. These lineages are genetically dissimilar from other species in the genus, but before the lineages can be considered a new species Demos will have to identify “clearly diagnosable differences,” such as physical traits or behaviors that set the new species apart. (Watch: “A Rare Look at Mexico’s Carnivorous Bats.”)
Demos is confident that the two new species will hold up to such scrutiny, and says there may even be more out there, since many of this group’s populations have never been surveyed.
Bring on the Bats
Though bats are the largest group of mammals, they are notoriously understudied. The remote areas they inhabit and the wide range of diseases they carry makes studying wild bats very difficult, and even dangerous.
But thanks to recent advancements in genetic sequencing technology, it is becoming a lot easier. Scientists can now “unlock DNA from the samples that might be hundreds of years old, and that helps a lot, because we can actually identify species that might be in a landscape that we can't get to,” says Susan Tsang, a genetics research associate the American Museum of Natural History in New York City who was not involved with the study.
Both Tsang and Demos believe that future genetic surveys will uncover dozens, if not hundreds, of currently unidentified bat species.
“It's interesting to know what evolutionary forces have driven and maintained the current diversity of mammals in Africa, but more practically, we need to have an accurate inventory of how many species there are so we can identify biodiversity hotspots and preserve them,” Demos says. (Read: “Deadly Bat Fungus Spreading in U.S.”)