Toothless 'dragon' pterosaurs once ruled skies

Ancient winged reptiles called pterosaurs were so successful that they ruled Earth's skies for tens of millions of years, according to a study published in the journal ZooKeys.

The fearsome fliers, part of a family of pterosaurs named Azhdarchidae, get their name from azdarha, the Persian word for "dragon." Unlike earlier pterosaurs, they had no teeth, and they dominated from late in the Cretaceous period (around 90 million years ago) until the extinction event that also killed off the dinosaurs some 66 million years ago.

“This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand,” study author Alexander Averianov of the Russian Academy of Sciences wrote in the paper.

Pterosaurs are not dinosaurs, and they're definitely not ancient birds, which are the living descendants of the dinosaurs. But understanding these large predators can give insight into the ancient ecosystem as well as the origins of flight, as pterosaurs are thought to be the first animals after insects to develop powered flight.

Pterosaur fossils are tough to find, the study authors point out, because their fragile bones haven’t survived as well as dinosaur remains have.

“Pterosaur bones were thin and fragile, much like bird bones, and they often drifted apart, shattered, or became scrambled before they could be preserved,” according to the American Museum of Natural History.

Thus, it’s often pretty difficult to tell how the few fossils that do exist are related to one another, according to the paper.

“Azhdarchidae currently represents a real nightmare for pterosaur taxonomists: Most taxa are known from few fragmentary bones, which often do not overlap between named taxa, the few articulated skeletons are poorly preserved,” Averianov wrote, and some of the best material “has remained undescribed for 40 years.”

For the ZooKeys study, Averianov surveyed and analyzed the known research to help straighten out the fossil record. The findings also showed that although their bones are challenging to find, the pterosaurs were probably quite successful in a wide variety of habitats, but were more commonly found near large lakes and rivers and especially in near-shore marine environments.



Reposted Copyright © 2014, Los Angeles Times 

Pterosaur's Wing, "Hairs" Unlike Any Living Animals'

By literally shining new light on a Chinese pterosaur fossil, researchers have found that the membranes in the creature's wings contain a complex pattern of fibers not found in any living animal.

The membrane structure may have given some pterosaur species better control when they took to the skies, a new study says.

The fibers "would have made it easier to make subtle adjustments of the wing membrane when flying, perhaps giving them better flight capability," said study co-author Alexander Kellner, a paleontologist at Brazil's Museu Nacional (National Museum) in Rio de Janeiro.

The well-preserved fossil also included hairlike fibers quite different from the hair on modern mammals.

Similar fibers had been found on pterosaurs before, but researchers had wondered if they were simply products of tissue decay.

The newly examined pterosaur has the hairlike fibers all over its body and part of its wings. This suggests that the fibers were a covering that may have helped the pterosaurs control their body temperatures, Kellner said

Found in a slab of Chinese shale loaded with ancient crustaceans and ash, this 135-million-year-old fossil has some of the best preserved soft tissue yet found in a pterosaur, researchers said in an August 2009 study.

New analysis of the creature's wings has shown that it had uniquely complex wing membranes and a covering of fibers quite different from the hair on modern mammals.

Photograph courtesy Alexander Kellner

Pterosaurs—Lords of the Ancient Skies

Parallel fibers that stiffened a pterosaur's wing membrane—each just two-thousandths of an inch (0.05 millimeters) thick—are visible in this fossil of a Rhamphorhynchus. The fossil was found in Germany's Solnhofen limestone beds, where incredibly fine grain preserves minute details.


... "Pterosaurs were just the coolest things that were ever in the air," says Padian. "They were the first vertebrates to fly. They did it long before birds and bats. And it terms of size, they pushed the envelope as far as it could go for a flying animal."

Like their cousins the dinosaurs, pterosaurs stand out as one of evolution's great success stories. They first appeared during the Triassic period, 215 million years ago, and thrived for 150 million years before going extinct at the end of the Cretaceous period. Their endurance record is almost inconceivable compared with the span of humans, whose ancestors started walking upright less than four million years ago. Uncontested in the air, pterosaurs colonized all continents and evolved a vast array of shapes and sizes. Of more than 120 named species, the smallest pterosaur measured no bigger than a sparrow; the largest reached a wingspan of nearly 40 feet (12 meters), wider than an F-16 fighter.

Until recently most paleontologists would not have put pterosaurs in the same league as birds in terms of flying ability. Because pterosaurs were reptiles, generations of scientists imagined that these creatures must have been cold-blooded, like modern snakes and lizards, making them awkward aerialists at best.

In the past three decades, however, a surge of fossil discoveries around the globe has prompted researchers to reexamine their views. The emerging picture of pterosaurs reveals that they were unlike any modern reptile. From a fossil discovered in Kazakhstan, paleontologists suspect that pterosaurs had a hairlike covering, perhaps akin to fur. If so, this detail provides evidence of a high-revving, warm-blooded physiology that could sustain the kind of exertion needed to stay in the air. Judging from the skulls of other fossils, scientists reason that many pterosaurs were gifted air-borne predators, built to feed on the wing. They darted after insects, dive-bombed for fish, and soared hundreds of miles over open ocean on extended hunting expeditions.

Pterosaurs Took Flight on All Fours

Pterosaurs took flight using all fours, a discovery that flies in the face of previous research on the ancient reptiles, a new study says.

Two of the giant creatures' "legs" were extremely strong wings, which when folded, created "knuckles" that allowed the animals to walk and jump (above left, the pterosaur known as Hatzegotpteryx in an artist's rendering).

The way a bird lifts off—using two legs—doesn't make sense for pterosaurs, which would have had to heave their 500 pounds (227 kilograms) airborne using only their hind legs, the study says.

Instead, the "remarkably strong" animals apparently made a leaping launch in less than a second from flat ground, with no aid from wind or ledges.

"Most people are familiar with images of pterosaurs as very skinny, almost emaciated-looking things—basically a hang glider with teeth," study author Michael B. Habib, of Johns Hopkins University School of Medicine, told National Geographic News. "They're actually built a lot more like Arnold Schwarzenegger than Urkel."

Habib compared bone strength in 20 species of modern birds and 3 species of pterosaurs to develop the new model, announced yesterday by the journal Zitteliana.

The finding is also consistent with the idea that bigger animals require more overall brawn to power their movement, Habib added.

"We put V8 engines in our biggest, heaviest cars, not V4s, like the one in my Camry."

—Christine Dell'Amore

Illustration by Mark Witton

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New Giant Toothless Pterosaur Found

With a wingspan longer than a full-size sedan, a new species of pterosaur dubbed Lacusovagus magnificens, or "magnificent lake wanderer," is the largest of its kind yet found, a new study reports.

The ancient flying reptile (seen at left in an artist's reconstruction) is also the first Chaoyangopterid—a family of toothless pterosaurs—found outside of China, noted Mark Witton, the University of Portsmouth researcher who named the species based on a partial skull fossil.

Witton made his discovery after examining remains from Brazil's Crato formation, layers of limestone that roughly date to the early Cretaceous period, about 115 million years ago.

The site, once a brackish lagoon, has yielded several other pterosaur species, but so far the skull fragments Witton analyzed represent the only existing Lacusovagus fossil.

The skull's size suggests that the Brazilian pterosaur had a roughly 16-foot (5-meter) wingspan and stood about 3.3 feet (a meter) high at its shoulders. With its long neck and jaw, the animal would have seemed as tall as a typical adult human (right).

"Some of the previous examples we have from this family in China are just 60 centimeters [24 inches] long—as big as the skull of the new species," Witton said in a university statement.


"Put simply, it dwarfs any Chaoyangopterid we've seen before by miles." 

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Pterosaur "Runway" Found; Shows Birdlike Landing Style

Like a prehistoric dance-step diagram, a patch of fossilized beach in France spells out the sequence of a pterosaur's landing, an August 2009 study says.

The "runway" suggests the birds landed like most modern birds, flapping their wings to slow down just before hitting the ground.

Photograph and illustration courtesy Jean-Michel Mazin via Kevin Padian


The first fossil footprints of a landing pterosaur have been discovered, a new study says.

The tracks offer rare insight into a dinosaur-age mystery: How did these flying reptiles move?

Whereas walking dinosaurs left footprints, a pterosaur in mid-flight would have left little more than droppings.

This critical difference has made analyzing pterosaur flight much harder than studying the gaits of their dinosaur cousins.

The 140-million-year-old pterosaur tracks, found along a long-gone lagoon in what is now southwestern France, could help change that.

Flying-reptile footprints are so common at the late-Jurassic-period site that paleontologists call it Pterosaur Beach. But from the start, it was obvious the newfound cluster is one of a kind.

"When my co-author showed it to me and said what he thought it was, it seemed both obvious and cool to me," said study co-author Kevin Padian at the University of California, Berkeley.

"It's great to have a landing track." 


How the Pterosaur Landed: Story in Stone

Like a dance-step diagram, the footstep fossils tell the sequence of the animal's movements as it landed.

The pterosaur first put its back feet down together and dragged its toes slightly. It then hopped back into the air for a moment before dropping onto its back feet a second time.

The flyer then looks to have lowered its wings, which had "hands" on either end, taken a step or two, turned, and walked off on all fours. (See "Pterosaurs Took Flight on All Fours.")

The relatively few landing tracks suggest that the pterosaur landed like most modern birds, flapping quickly right before landing to slow themselves down, the researchers say. (A few modern-day birds come in for a running landing, leaving lots of footprints.).

As exciting as the landing track is, Padian said, it's still solves only part of the mystery. "It would be equally cool to have a takeoff track." 

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Toothy Texas Pterosaur Discovered; Soared Over Dallas

John Roach for National Geographic News

Long before six flags flew over Texas, a newfound species of winged reptile with an exceptionally toothy grin owned the skies over what is now the Lone Star State.

The recently discovered pterosaur, dubbed Aetodactylus halli, was identified based on a 95-million-year-old lower jawbone found outside of Dallas by amateur fossil hunter Lance Hall. 

The pterosaur had a relatively slender jaw filled with thin, needlelike teeth, which might have helped the creature pluck fish from the shallow sea that once covered the region, a new study says.

"It was hanging out near the ocean, and that is probably where it derived its food from," said study leader Timothy Myers, a paleontologist at Southern Methodist University in Dallas.

By comparing the jawbone to more complete pterosaur fossils, Myers and his team think A. halli was a medium-size animal with a nine-foot (three-meter) wingspan and a short tail.

Texas's Toothy Pterosaur a Rare Find

Pterosaurs ruled the skies from the late Triassic period, more than 200 million years ago, until dinosaurs went extinct at the end of the Cretaceous, about 65 million years ago.

At 95 million years old, A. halli is one of the youngest members yet found in the Ornithocheiridae family of toothed pterosaurs, Myers said.

Despite being common elsewhere in the world, toothed pterosaur fossils are rare in Texas: A. halli is only the second ornithoceirid yet discovered in North America. 

The new pterosaur had 54 teeth in its lower jaw, which is an unusual amount for ornithoceirids, Myers added. Most other members of the family had just 30 lower jaw teeth. Only Boreopterus, a relative from the same time period found in China, is known to have had as many teeth as A. halli.

When the animal lived, a giant north-south interior seaway split North America from the Gulf of Mexico to the Arctic Ocean, putting what is now Dallas underwater.

A. halli's jawbone was found in marine rocks exposed near a highway in Mansfield, southwest of Dallas, which would have been the southernmost end of the ancient sea. No other fossils from the animal have been unearthed nearby, Myers said.

"It could be that something caused the pterosaur to die and fall into the water," he said. "Decay started, and the lower jaw just fell off and got separated from the rest of the body."


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Pterousaurs - Flying Dinosaurs!

Pteranodon, the most famous of all pterosaurs (American Museum of Natural History)

Pterosaurs ("winged lizards") hold a special place in the history of life on earth: they were the first creatures, other than insects, to successfully populate the skies. The evolution of pterosaurs roughly paralleled that of their terrestrial cousins, the dinosaurs.

Paleontologists have found indisputable proof that modern birds are descended not from pterosaurs, but from small, feathered, land-bound dinosaurs (in fact, if you could somehow compare the DNA of a pigeon, a Tyrannosaurus Rex and a Pteranodon, the first two would be more closely related to each other than either would be to the third). This is an example of what biologists call convergent evolution: nature has a way of finding the same solutions (wings, hollow bones, etc.) to the same problem (how to fly). Learn More About Pterousaurs Here
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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Flying Dinosaurs - Eudimorphodon

Although it's not nearly as well known as others of its kind, Eudimorphodon holds an important place in paleontology as one of the earliest pterosaurs: this tiny, winged reptile hopped around the shores of Europe a whopping 210 million years ago, during the late Triassic period. Eudimorphodon possessed the wing structure--forelimbs embedded in an extended flap of skin--characteristic of all pterosaurs, as well as a diamond-shaped appendage at the end of its tail that probably helped it to steer or to adjust its course in mid-air. (By the way, despite its name, Eudimorphodon wasn't particularly closely related to Dimorphodon, beyond the fact that they were both pterosaurs.)

_______________________________________________________________
Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).