The bones of the tiny mammal were found at a fossil site in 1999, unearthed when a new high-speed train track was built east of Brussels, but researchers spent decades sifting through tonnes of soil to make the discovery.
Eventually they encountered the bones of a tiny bat, from the myotis or mouse-eared bat genus, barely changed from those commonly found in Europe today. This discovery has led to the bat being baptised ‘Myotis belgicus’.
Senior palaeontologist at the Institute, Thierry Smith, said that the discovery was unexpected because most rodents have a complex evolutionary history.
The Belgian discovery shows that the previous estimate of when such bats appeared for the first time was off by some seven million years.
Smith explained the long life of the bat species could be explained by the fact that bats are the only mammal capable of flying and as such did not need to compete with others for resources.