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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
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Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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4 August 2004 (All day)
With an impressive array of feathers, the 147-million-year-old Archaeopteryx is clearly dressed like a bird. But almost all of its skeleton, from its teeth to its long, bony tail, resembles that of a carnivorous dinosaur. Now, the first look inside the head of this classic transitional fossil reveals a fundamentally birdlike brain, well suited for flying.
Paleontologist Angela Milner of the Natural History Museum in London, U.K., and colleagues inspected the brain of the so-called London specimen of Archaeopteryx, one of seven known fossils of the magpie-sized creature. Although the brain itself isn't preserved, during life the brain pressed against the skull, leaving an impression of its lobes.
Working with paleontologist Tim Rowe and his imaging team at the University of Texas, Austin, the researchers scanned the 20-millimeter-long braincase with an industrial computerized tomography (CT) scanner, which has a higher resolution than medical CT scanners. They assembled the images by computer into a three-dimensional reconstruction of the brain (Science, 9 June 2000, p. 1728).Archaeopteryx's brain was much like that of modern birds, the group reports this week in Nature. For starters, it's big relative to body mass. With a volume of about 1.6 milliliters, its brain was three times larger than those of living reptiles. But it wasn't full-fledged: Modern birds, for their body size, have brains that are 33% to 500% larger than Archaeopteryx's.Birdlike features of the anatomy include enlarged cerebral lobes, compared with its reptile relatives. In living birds, these lobes process sensory information from the inner ear and muscles. "It's the command and control center for flight," Milner explains. That center was likely kept busy: Feeding into it were the optic lobes, each enlarged almost to the size of the cerebellum and located on the sides of brain--just as they are in birds and pterosaurs.The new view of the anatomy will help explain the evolutionary transition from dinosaurs to birds and the evolution of flight, says Lawrence Witmer, a paleontologist at Ohio University College of Osteopathic Medicine in Athens. "Archaeopteryx was agile, quick, and jerky in its movements," says Witmer, who likens the extent of its acrobatics more to those of a chicken than to those of a falcon or swallow. Even though Archaeopteryx lacked some of the skeletal features needed to fly like an eagle, it appears to have evolved all the brains for it.