Belgian Discovery: Popular Bat Genus Is Millions of Years Older Than Thought




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Myotis (CC Manuel Ruedi)
Belgian Discovery: Popular Bat Genus Is Millions of Years Older Than Thought
post by
Jonas Van Boxel

Our palaeontologists have found the oldest fossil of the extant bat genus Myotis (mouse-eared bat). This proves that the widespread genus has existed at least 7 million years earlier than previously assumed.

Bats make up over one fifth of all living mammal species. The group of the Vespertilionidae or vesper bats is the most diverse and in that group, the genus Myotis is the most successful. It consists of more than 120 living species, which are distributed on all continents except Antarctica. It is only rivalled by humans in its distribution around the globe.

The Oldest One Found in Belgium

The time of divergence of the Myotis genus, as well as the Vespertilionidae group, has been contentious. Myotis fossils are abundant, especially in Europe, but few date back to before the Miocene (23 to 5 million years ago). But in 1999, Richard Smith, a palaeontologist at our Institute, found the remains of a relatively large vesper bat from the Oligocene (33 to 23 million years back) in Boutersem, Flemish Brabant.

Recently, Thierry Smith – our colleague and Richard’s son – together with Gregg Gunnell (Duke University) concluded that they belong to the Myotis genus. This Myotis belgicus is 33.5 million years old, at least 7 million years older than previously estimated.

Flexible Animals

The palaeontologists researched the first fossil appearance data of 1.011 extant placental mammal genera. They concluded that only 13 of them appeared first in the middle to late Palaeogene (48 to 33 million years ago), among which, 6 of them are bat genera, including Myotis. Bats thus appeared sooner than most mammal species. Their successful adaptation skills resulted in fast evolutionary diversification, during the Early Eocene Climatic Optimum (a period of rapid global warming 52 to 50 million years ago).

This research was published in the journal PLOS ONE

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