Two fossilized bat skeletons unearthed in western Wyoming characterize a brand new species and are the oldest set of bat bones but found, researchers say.
The extremely full fossils of Icaronycteris gunnelli, which present all of the animals’ bones in lifelike positions, are from limestone rocks that amassed as lake sediments about 52.5 million years in the past, vertebrate paleontologist Tim Rietbergen and colleagues report April 12 in PLOS ONE. Skeletons of the few different bat species, together with one other one from the Icaronycteris genus, present in the identical limestones, known as the Inexperienced River Formation, have been preserved at the least 40 centimeters above the brand new fossils — and are thus youthful.
However it’s tough to estimate simply how a lot youthful these fossils are as a result of researchers don’t know the way quickly sediments amassed over time, says Rietbergen, of the Naturalis Biodiversity Heart in Leiden, Netherlands.
An evaluation of the newfound skeletons signifies I. gunnelli is the runt of its genus. The species has a wingspan, usually estimated from the size of forearm bones, that’s nearly 7 % smaller than that of the bat’s closest identified cousin, Rietbergen and colleagues say. Throughout its lifetime, I. gunnelli weighed someplace between 22.5 and 28.9 grams — roughly half as heavy as a tennis ball, the workforce calculates.
These skeletons “are an excellent discovery,” says Zhe-Xi Luo, a vertebrate paleontologist on the College of Chicago who was not concerned within the examine. The association of bones in I. gunnelli’s ft recommend that it, like many fashionable bats, hung the other way up when roosting, he says.
As a result of the skeletons are a lot like these of some fashionable bats, “we’re not any nearer to realizing what sort of creatures bats advanced from,” says Brock Fenton, a vertebrate paleontologist on the College of Western Ontario in Canada, who additionally was not concerned with the work. The world’s oldest identified bats lived about 56 million years in the past, however the fossils of these species are principally remoted tooth, not complete skeletons.
