LOS ANGELES, Jan. 29 (Xinhuanet) -- Researchers have constructed a family
tree for bats using genetic information, according to a paper published in this
week's Science journal.
Bats' evolutionary history is poorly understood even though they make up nearly 20 percent of
all mammals. Scientists have estimated that approximately 60 percent of the bat
fossil record is still missing.
But a research group led by Emma Teeling at US National Cancer Institute
compared genetic sequences from each modern-day bat family. They also
reconstructed the evolutionary relationships among the microbats that use
echolocation and the megabats that donot.
Moreover, they traced the paleogeographic origins of the major bat
lineages. The results support the hypothesis that megabats arenested among four
major microbat lineages, which originated in theearly Eocene (around 50 million
"With well over half of the Cenozoic history missing for microbat lineages
and nearly all of the fossil history missing formegabat lineages, it is not
surprising that Paleocene bat ancestors having transitional morphological
adaptations for flightand echolocation have never been discovered," they wrote
in the paper.
This was also the time of a significant global rise in temperature and an
increase in plant and insect diversity, indicating that bats diversified rapidly
in response to a similar trend in their prey, researchers said.
"Their results give us a new framework for understanding bat evolution, but
it is only the tip of the iceberg," commented NancySimmons, zoologist at the
American Museum of Natural History.
"As flying predators capable of capturing prey on the wing, they would have
had few competitors for the rich resources of the Eocene night," she wrote in a
commentary in the same issue of Science. Enditem