by John Davis
Texas Tech Bat Researchers Discover New Species on St. Vincent Island
Image of St. Vincent team (left-right) Peter Larsen, Scott Pedersen, Fitzroy Springer and Brandon Bales. Click to Enlarge.
At first glance, the bat captured in St. Vincent looked like a common type found in South America.
But after closer inspection, Texas Tech University biologists discovered a new species found only on the Caribbean island and whose origins probably trace back to a dramatic marooning during the end of a recent ice age.
The discovery was made by Peter Larsen, a postdoctoral research assistant in the Department of Biological Sciences, and Lizette Siles, a graduate student of zoology. It was published in November 2011 in the peer-reviewed journal, Mammalian Biology.
Researchers from the University of Scranton, South Dakota State University and the University of Nebraska also contributed to the discovery.
As a way of honoring St. Vincent’s inhabitants, the researchers have named the bat Micronycteris buriri. Buriri is the Garifuna word for bat, and the Garifuna are the blended culture of Carib, Arawak and West African peoples that trace their ancestry back to St. Vincent.
Larsen said he went to St. Vincent in 2005-2006 on two expeditions with a team of researchers seeking to categorize bat diversity on the island.
“We didn’t know at the time when we caught this particular species that it was a new species,” he said. “We thought it was a species that had already been described in South America. A year or so went by, and I happened to look at this species that we had collected and compared it to what we thought it was, a species from Trinidad. But the St. Vincent bat was huge, comparatively speaking.”
Larsen gave the sample to Siles, who is an expert in neotropical bat morphology. After looking at the teeth and the skull, she determined the bat from St. Vincent was distinct from its closest South American relatives. Though these relatives are smaller, often small animals grow larger and large animals grow smaller when introduced onto an island.
Researchers say the bat's ancestor most likely island-hopped to St. Vincent during one of the Pleistocene's ice ages.
Larsen said that though the island effects on the body size may have played a role in this example, the species on St. Vincent is genetically distinct and has species-level differences in body type, which is how the team determined that the bat was a new species to science.
“Its size was the first clue,” Siles said. “It’s a very large bat in body and skull size compared to its mainland counterparts. Also it differs in specific skull and teeth characteristics. The lower incisors are a lot larger than they are wide. That’s completely different than the one he thought it was. At the base of the skull where the ear is there are supposed to be two wells. Those wells are very shallow. On the mainland species, they’re very deep.”
The new species came about fairly recently, the researchers said, probably sometime in the last 600,000 to 1 million years. Prior to this, the bat’s common ancestor from the South American mainland managed to island-hop across to St. Vincent when sea levels were much lower.
The marooning likely occurred during one of the Pleistocene’s ice ages, which raised sea levels and isolated the St. Vincent population.
Siles said the bat is mainly an insect eater that will roost in caves, trees and even logs on the forest floor.
However, the animal has an uncommon method for catching prey, she said.
They can actually pick off their insect prey off the surface of rocks and leaves,” Siles said. “Not all insectivores can do that, because most insectivores catch their prey on the fly. Their big ears, wide wings and membranes between the rear feet and tail allow them to maneuver better.”
Feature image of new bat species Micronycteris buriri. Full size image.
Meet the Researchers
Peter Larsen is a postdoctoral research assistant in the Department of Biological Sciences at Texas Tech University. Larsen received his master's in biological sciences at TTU and his undergraduate degree from South Dakota State University.
Lizette Siles is a Ph.D. student in the Department of Biological Sciences at Texas Tech University. She also is a research assistant in the Mammal Collection at the Natural Science Research Laboratory, a branch of the Museum of Texas Tech University. Siles received a Bachelor of Science in Biology from the Universidad Mayor de San Simón, Bolivia.
John Davis is a Senior Writer in the Office of Communications & Marketing at Texas Tech University. Photos courtesy Peter Larsen.