Six New Prehistoric Bat Species Discovered in Egypt
Steven Stanek in Cairo, Egypt
for National Geographic News
|March 6, 2008|
Six new species of ancient bat dating back 35 million years have been discovered in Egypt, researchers say.
The new species were found by experts who analyzed 33 fossils—including teeth and jawbones—that had been unearthed over a period of decades in El Faiyum, an oasis region 50 miles southwest of Cairo (see map).
"It is [a] surprising diversity of new forms—we didn't expect to find nearly as many new kinds of bats as we found in the sample," said Gregg F. Gunnell, a paleontologist at the University of Michigan who led the study.
The experts were also surprised to find that the new species were similar to some modern-day microbats, a group of bats that uses sonar waves to navigate and hunt in a process called echolocation.
"They are all pretty primitive members of modern groups, which is a little bit odd," Gunnell said.
"Generally in [this period in the fossil record], you tend to [find] archaic bats but nothing very modern, but these animals are all members of living families."
The link is the best evidence yet that modern bats evolved on the African continent rather than in the Northern Hemisphere, as some have theorized.
"In a sense, Africa is sort of a crucible for the evolution of the modern bats," Gunnell said.
Among the newly discovered species was a previously unknown "giant" version of the microbat family, which makes it perhaps the largest of the echolocating species yet found.
The newfound fossil bats date to the Eocene epoch—56 million to 34 million years ago—and such finds are rare in Africa, the experts say.
Only a few fragmentary remains from Egypt, Morocco, Tanzania, and Tunisia have ever been discovered (see map of Africa).
"You simply don't find them very often," Gunnell said, noting that the 33 specimens took decades to accumulate.
The rare samples were collected by Duke University paleontologist Elwyn L. Simons, who has been digging for animal fossils in el Faiyum since the 1960s.
Simons said Egypt, particularly el Faiyum, holds the best fossil records in Africa from the period between 37 million and 27 million years ago.
(See related news photos: "Egypt's Earliest Farm Settlement Discovered" [February 12, 2008].)
"[This ten-million-year span] is a big slice of Earth history as far as Africa is concerned," Simons said.
"[Africa] is a high-standing continent—that means it doesn't have a lot of sedimentary basins [with deposits that yield] ancient mammals—but Egypt does."
The bat fossils were set aside for many years until the recent study, which looked into the details of the teeth to determine the similarities and differences with other bat species.
From the 33 fragments, experts determined that at least six distinct species could be parsed out.
The names of the new species will be revealed in an article in an upcoming issue of the Journal of Vertebrate Paleontology.
Experts were able to link an upper and lower jawbone and several teeth from different individual bats to a previously unknown "giant" species of microbat.
"It is probably one of [the largest], if not the largest, microbat that has ever been found," said Erik R. Seiffert, a paleontologist at New York's Stony Brook University who has been digging with Simons since 1999.
"It is quite surprising actually."
Microbats are smaller than megabats, or fruit bats, which only are found in the tropical climates and rely on their sense of smell rather than echolocation.
(See related photo: "Bizarre Horseshoe Bat Photographed for First Time" [June 22, 2007].)
Gunnell said the larger microbat could have had a wingspan close to 2 feet (0.6 meter). Modern-day megabats, by comparison, have wingspans as wide as three feet (about a meter).
"It would have been loud—it would have been obnoxious," Gunnell said.
"Just going by the large echolocating bats that I know that live today many are very loud and very pushy and very boisterous. I am assuming these bats would have been, too."
The paleontologists say the diversity of species discovered in El Faiyum is the strong evidence that bat species evolved in Africa.
The prevailing theory had held that primitive bats came to resemble modern bats over a long period of evolution that occurred in the northern continents, according to Seiffert.
The only fossil bats found in the Northern Hemisphere, however, have been extremely primitive species with much less resemblance to modern bats.
"This [new study] definitely provides some really compelling fossil evidence that modern [microbats] may actually have had an African origin," Seiffert said.
Gunnell said he thinks a primitive bat species made its way to Africa some 50 million years ago, "then differentiated into these more modern forms."
"Africa may have played an important role as kind of an incubator for the evolution of new animals," he said.
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