Jewish World Review
http://www.jewishworldreview.com | (KRT) Pterodactyls, the fierce-looking flying reptiles that thrived in the days of dinosaurs - some with wingspans as wide as a Learjet - came equipped with flight instrumentation that should make 21st Century aeronautical engineers envious.
A team of American paleontologists used powerful industrial-strength CT scans to capture the first pictures of the inside of the braincase of two species of pterosaurs, the scientific grouping of the strange flying creatures popularly known as pterodactyls.
Those pictures are being hailed by paleontologists as a breakthrough, revealing how the earliest flying vertebrates developed an extraordinary physiological flight apparatus that made them more sophisticated and efficient fliers than today's birds and bats.
The findings, published in Thursday's issue of the British science journal Nature, are part of a growing body of research giving scientists a much deeper, entirely different idea of how the reptiles flew.
In the new work, a team headed by Ohio University Osteopathic Medical College anatomy professor Lawrence Witmer used CT scans of the two pterodactyl skulls to study tiny inner-ear canals and outsized brain lobes called the flocculus, which link brain activity with body movement. Birds and bats, the only other vertebrates to master flight, also have a flocculus, but pterosaur flocculi are much bigger relative to the size of the rest of their brains.
Witmer's research centered mostly on how pterodactyls performing aerial maneuvers kept their eyes focused on prey on the ground or in the water.
Other pterosaur experts, however, like David Unwin, a Humboldt University paleontologist in Berlin, already are linking Witmer's findings to recent discoveries of complex muscle structures in Pterosaur wings, so sensitive that the wings acted almost like sensory organs.
"You have a `smart wing' in a pterosaur, monitoring the loads on the wing," Unwin, one of the world's leading pterosaur authorities, said in a telephone interview Wednesday.
It appears, he said, that pterodactyls used the flocculus as a sort of data relay station.
Witmer said that as a pterodactyl soared through the air, sensitive muscle fiber near the surface of the skin on its wings sent continuous streams of data on wind speed, temperature, body attitude, position and tension of wings to the brain through the flocculus.
The brain could then send instructions back to the pterodactyl's wing through the flocculus, changing the tension on the skin, causing subtle changes in the shape of the wings to alter flight speed or direction.
"It is an amazing structure," Unwin said. "They must be very effective fliers. They pushed the envelope aeronautically. Birds certainly don't have that sort of thing. Maybe bats have this, but nobody has looked, so far as I know."
Like dinosaurs, to which they are closely related, pterodactyls were one of Earth's most successful life forms. They evolved from lizardlike creatures, shortly after dinosaurs arose, and went extinct with the dinosaurs.
Fossils of about 100 pterosaur species have been discovered, ranging from the smallest, about the size of a sparrow, to the largest, creatures called Azhdarchids, that had wingspans of about 40 feet.
Pterosaurs were carnivorous; most preyed on fish rather than land animals.
Scientists had known that, relative to the size of the animal, the flocculus in pterosaurs was much larger than in birds and bats. But Witmer said he wanted to find out why it was larger and turned to the CT scan to find answers.
For the last several years, paleontologists have enlisted the help of industrial CT scans to look at fossilized bones - particularly skulls - to try to spot tiny anatomical structures almost impossible to find in any other way.
The soft tissue of organs is gone, but the telltale bone cavities that once contained the organs, even tiny inner-ear structures, remain intact in fossil skulls. Medical CT scans usually are not powerful enough to detect those cavities, but they can be picked up by industrial CT scans used to examine huge pieces of machinery for tiny cracks and flaws.
Intact pterosaur skulls, however, are extremely rare. As flying animals, their bones were hollow, delicate and extremely lightweight.
The heavy bones of dead dinosaurs could sink deeply into mud and fossilize. But when pterosaurs died, few sank into the mire that would make a fossil. Those that did nearly always were badly broken and squashed by geologic forces.
Witmer did manage to borrow two intact pterodactyl skulls from museums, a 4-inch-long skull of a crow-size species called Rhamphorhynchus that lived 150 million years ago in Germany, and the 20-inch skull of a species called Anhanguera that 115 million years ago used its 14-foot wingspan to soar over what is now Brazil.
Witmer teamed up with Sankar Chatterjee of Texas Tech University and Jonathan Franzosa and Timothy Rowe of the University of Texas to scan the skulls at the University of Texas.
The team scanned tiny, delicate brain structures to analyze brain regions in both the skulls that coordinated the wing movements and controlled their ability to scan water surfaces for fish - both were fish predators.
The flocculus cavity in both skulls accounted for about 7.5 percent of their brain mass, while in most birds the flocculus accounts for about 2 percent.
"They (pterosaurs) recruited the wing as this extra sensory organ and linked it with neck, head and, ultimately, eye movement," said Witmer.
"The body can change position, but the eyes stay focused on their prey."
Witmer teaches human anatomy to medical students, but his research concentrates on comparing fossilized animals with living animals to glean clues about the behavior of extinct animals. "Human anatomy is well-understood," he said. "Pterodactyls have the same parts you and I have; they're just arranged a little differently."
His work has caused dinosaur experts in the past to reconsider the location of nostrils on the faces of beasts they study. Unwin said he is delighted Witmer turned his attention to pterosaurs.
"I feel extremely jealous that people who don't normally do work on pterosaurs have found something every pterosaur expert would love to take credit for," he said. "It's a big step forward in our knowledge."
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