Although there are slightly older fossil bat teeth from Asia, those of I. gunnelli are the oldest skeletons found.
A new species of extinct bat has been described with the oldest skeletal remains recovered, corresponding to a specimen that lived 55 million years ago in the present day. Wyoming.
The study supports the idea that bats diversified rapidly across several continents during that time. Led by researchers at the American Museum of Natural History and the Naturalis Center for Biodiversity in the netherlandsthe study is published in the journal PLOS ONE.
There are more than 1,460 living species of bats found in almost every part of the world, with the exception of the polar regions and some remote islands. In the Formacin Green River From Wyoming, a remarkable deposit of fossils from the early Eocene, scientists have discovered more than 30 bat fossils in the past 60 years, but until now they were all thought to represent the same two species.
“Eocene bats have been known from the Green River Formation since the 1960s. But, interestingly, most of the specimens that have emerged from that formation were identified as representatives of a single species, index Icaronycterisuntil about 20 years ago, when a second species of bat belonging to another genus,” the study co-author said in a statement. Nancy SimmonsCurator-in-Charge of the American Museum of Natural History’s Department of Mammalogy, who helped describe that second species in 2008. “I always suspected there must be even more species out there.”
In recent years, scientists at the Naturalis Biodiversity Center began to take a close look at the Icaronycteris index by collecting measurements and other data from museum specimens.
“Paleontologists have collected so many bats that they have been identified as index Icaronycteris, and we wondered if there were actually multiple species among these specimens,” he said. Tim Rietbergen, Naturalis evolutionary biologist. “Then we found out about a new skeleton that diverted our attention.”
The exceptionally well-preserved skeleton was picked up by a private collector in 2017 and purchased by the Museum. When the researchers compared the fossil to Rietbergen’s extensive dataset, it clearly stood out as a new species. A second fossil skeleton discovered in the same quarry in 1994 and in the collections of the Royal Ontario Museum was also identified as this new species. The researchers gave these fossils the species name Icaronycteris gunnelli in honor of Gregg Gunnell, a paleontologist at Duke University who died in 2017 and made extensive contributions to the understanding of fossil bats and evolution.
Although there are slightly older fossil bat teeth from Asia, the two I. gunnelli fossils represent the oldest bat skeletons ever found.
“The Fossil Lake deposits of the Green River Formation are simply amazing because the conditions that created the paper-thin limestone layers also preserved almost everything that settled to the bottom of the lake,” said Arvid Aase, park manager. and curator of Fossil Butte National Monument. , in Wyoming. “One of these bat specimens was found lower in the section than all other bats, making this species older than any of the other bat species recovered from this deposit.”
Although the I. gunnelli skeletons are the oldest bat fossils at this site, they are not the most primitive, supporting the idea that Green River bats evolved separately from other Eocene bats worldwide.
“This is a step forward in understanding what happened in terms of evolution and diversity in the early days of bats,” Simmons said.
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