The tiny bumblebee bats of Thailand and Myanmar (Craseonycteris thonglongyai) are widely considered the Earth’s smallest mammal.© Daniel Whitby
A new study based on the largest bat genome and fossil study ever conducted has found that bats most likely arose in Europe around 65 million years ago, overturning previous assumptions.
The study, published today in the journal
“This study is a game-changer for our understanding of bat evolution,” said Nancy Simmons, curator emeritus in the Museum’s Mammalogy Department and one of the authors on the new study. “By combining data from whole genomes with fossils, we now have a new and robust framework for understanding how, when, and where many of the amazing traits of bats evolved.”
The team assembled the largest collection of high-quality bat genomes to date, including 103 species and representing all currently recognized 21 bat families. They combined this genomic data with details from 44 fossil bats from across the globe to redraw the bat family tree.
“Reconstructing the evolutionary history of bats turned out to be much more complex than simply building a bigger tree with more data,” said Museum Research Associate Ariadna Morales, the lead author of the study, from The City College of New York. “Different regions of the genome can preserve different evolutionary histories, so a major effort in this study was to systematically identify and compare those signals and the alternative topologies they support. The result is not only a revised evolutionary tree of bats, but a genomic resource that the scientific community can build on to develop and test new analytical approaches.”
Among the findings: about 65 million years ago, bats, and with them mammalian flight, originated in Europe—not Asia, Africa or North America as long thought based on ancient bat fossils. The earliest bat descendants then dispersed into Africa, establishing a Europe-Africa hub from which bats then expanded into Asia, the Americas, and Australia.
The work also reveals that echolocation, like flight, evolved near the dawn of bat evolution, helping explain the extraordinary evolutionary success of bats. Today, bats account for one fifth of all living mammals and are found on six continents.
In addition, the research provides the first-ever reconstruction of the full set of chromosomes of the ancestor of all living bats.
Many bat species show remarkable resistance to disease and live exceptionally long lives for their size. The genomic resource built for this study gives scientists the first robust evolutionary framework to investigate the genes behind these traits. This work could eventually inform research into aging, immunity, and disease resistance.
“This study sets the stage for many new studies including those focused on understanding the genetic and immunological bases of how bats live such unusually long and healthy lives, including their exceptional cancer resistance,” Simmons said. “This was a major team effort in the bat community, and it should pay off for decades to come in stimulating all kinds of exciting and important research on bats.”
Morales added: “Collaborations at this scale create opportunities to train and engage researchers from diverse backgrounds and to build new collaborations that can continue well beyond this study.”