February 3, 2011
Rare Fossil Reveals 100 Million Years Of Evolutionary Stasis
Researchers have discovered the 100 million-year-old ancestor of a group of large, carnivorous, cricket-like insects that still live today in southern Asia, northern Indochina and Africa. The new find, in a limestone fossil bed in northeastern Brazil, corrects the mistaken classification of another fossil of this type and reveals that the genus has undergone very little evolutionary change since the Early Cretaceous Period, a time of dinosaurs just before the breakup of the supercontinent Gondwana.
The findings are described in a paper in the open access journal ZooKeys.
Although the fossil is distinct from today's splay-footed crickets, its general features differ very little, Heads said, revealing that the genus has been in a period of "evolutionary stasis" for at least the last 100 million years.
Other studies have determined that the region where the fossil was found was most likely an arid or semi-arid monsoonal environment during the Early Cretaceous Period, Heads said, "suggesting that the habitat preferences of Schizodactylus have changed little in over 100 million years."
L©a Leuzinger, a graduate student at the University of Fribourg, Switzerland, is a co-author on the study.
Image Caption: A fossil found in northeastern Brazil confirmed that the splay-footed cricket of today has at least a 100-million-year-old pedigree. Credit: Hwaja Goetz
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