How Did Pterosaurs Fly?

 

Visit the exhibition to experiment with principles of pterosaur aerodynamics in an interactive virtual tunnel.
© AMNH/D. Finnin

Flight allowed pterosaurs to travel long distances, exploit new habitats, escape predators, and swoop down from above to seize their prey. They spread across the world and branched out into an enormous array of species, including the largest animals ever to take wing.

BUILT TO FLY

Like other flying animals, pterosaurs generated lift with their wings. They needed to perform the same kinds of motions as birds and bats, but their wings evolved independently, developing their own distinct aerodynamic structure.

Nemicolopterus crypticus was recently discovered in northeastern China, in a region once dotted with wetlands, lakes, and forests. This tiny pterosaur may have darted through forests hunting for insects.
© AMNH 2014

Pterosaurs flew with their forelimbs. Their long, tapering wings evolved from the same body part as our arms. As pterosaurs’ arm and hand bones evolved for flying, they lengthened, and the bones of one finger—the equivalent of our ring finger—became extraordinarily long. Like the mast on a ship, these bones supported the wing surface, a thin flap of skin that was shaped like a sail.


WING BONES

Although many animals can glide through the air, pterosaurs, birds, and bats are the only vertebrates that have evolved to fly by flapping their wings. All three groups descended from animals that lived on the ground, and their wings evolved in a similar way: their forelimbs gradually became long, bladelike, and aerodynamic.

The medium-sized Istiodactylus evolved during the Cretaceous, and its contemporaries included the largest flying animals ever known, such as Pteranodon longiceps and Quetzalcoatlus northropi.
© AMNH 2014

Large pterosaurs needed strong limbs to get off the ground, but thick bones would have made them too heavy. The solution? A pterosaur’s wing bones were hollow tubes, with walls no thicker than a playing card. Like bird bones, they were flexible and lightweight, while strengthened by internal struts.

INSIDE THE WINGS

Recent discoveries show that pterosaur wing membranes were more than simple flaps of skin. Long fibers extended from the front to the back of the wings forming a series of stabilizing supports, so the membranes could be stretched taut, or folded up like a fan. Separate muscle fibers helped pterosaurs adjust the tension and shape of their wings, and veins and arteries kept the wings nourished with blood.

Rhamphorhynchus's long tail had a stiff flap of skin called a vane at the end that stabilized flight. Some scientists think this membrane faced sideways, like a fish tail, and helped prevent rocking from side to side. Others think it lay flat, like a paddle, and helped the flying pterosaur control its elevation.
© AMNH 2014

The exhibition includes a remarkable fossil of Rhamphorhynchus muensteri, discovered in Germany in 2001, which features wing tissues so well preserved that scientists have been able to see fine details in their structure. Under ultraviolet light, researchers detected layers of skin threaded with blood vessels, muscles, and long fibers that stiffened the wing. Because of the shadowy color of the wing membrane, paleontologists call this fossil Dark Wing.

The Pterosaurs exhibition includes a remarkable fossil of Rhamphorhynchus muensteri known as Dark Wing, which has allowed scientists to see fine details of pterosaur wing structure.
© AMNH/D. Finnin


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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 

Complete pterosaur eggs discovered in China.

 

The eggs are three-dimensional and extremely well-preserved (Picture: Rex)

 According to the famous scientific journal Current Biology on June 6, 2014, the world's largest and most well-preserved three-dimensional fossil cluster of pterosaur and its eggs were found in Hami, western China's Xinjiang Uygur Autonomous Region. The discovery was based on the field research of researcher Wang Youlin and his team of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, over the past 10 years. The specimens are named Hamipterus tianshanensis. "Hami" refers to the region where the specimens were found.The pterosaurs are thought to have perished in a large storm.

The discovery in the Xinjiang Uygur Region, western China, is the world’s largest and most well-preserved cluster of three-dimensional fossils ever found with a nest containing eggs.


 

Photo by HAP/Quirky China News/REX (3792156c) Artist's impression of Crested Pterosaurs

 
Pterosaurs were flying reptiles with wingspans ranging from 25 cm to 12 metres, and they lived together in large colonies.

The discovery represents a new genus and species known as Hamipterus tianshanensis.

Speaking to the journal Current Biology, field researcher Wang Youlin described the eggs as ‘three-dimensionally’ preserved.
 

Photo by HAP/Quirky China News/REX (3792156b) Artist's impression of Crested Pterosaur

The fossils were unearthed during a study conducted by a team from the Chinese Academy of Sciences, who have been excavating the fossil-rich region for the past 10 years.

Wang says that sediment samples in the area suggest the pterosaurs died in a large storm about 120million years ago.

Reposted from Metro

Baby Dinosaurs Discovered

Yunnan Province, China holds some very special eggs, containing the tiny bones of unborn sauropod dinosaurs. Within the Lufeng Formation, a relatively thin bed of red sediment contains these fossil eggs, mixed and buried amidst other fossils.

Robert Reisz from the University of Toronto and his fellow paleontologists working in the Yunnan province of China discovered a cluster of 200 tiny fossils bones left behind by ancient dinosaur embryos.  Upon further inspection it turned out to be the oldest remnants of dinosaur embryos ever discovered by human beings.

The scientists discovered the embryos in a layer of sedimentary rock. They date them to the early Jurassic Era, making them approximately 190 million years old. The fossils’ importance extends beyond their age, though. They are probably unhatched embryos of Lufengosaurus at different developmental stages, providing a unique opportunity to investigate the embryonic development of a prehistoric species.

The research team focused their analysis on the most prevalent and best-preserved bones: femurs, or thigh bones. These little leg bones ranged from 0.5 to 0.9 inches  in length, shorter than matchsticks. The bones were porous, filled with cavities that would have once allowed blood to flow to the growing tissue. The size of the cavities is determined by how fast the animal grows — which made researchers realize these embryos got big quickly.  The researchers also found an asymmetrical thickening in the femurs associated with muscle action on the bone. The finding suggests the baby dines were kicking and twitching inside their eggs.

Artist’s impression of embryonic Lufengosaurs. Credit: D. Mazierski (c) 2013

The fast growth rate makes sense, given that Lufengosaurus grew to gigantic size 20 feet (6 meters) in length.

Adult Lufengosaurus Credit: DK Images

Reposted from  Photo Editor

'World's largest dinosaur' discovered in Argentina

The largest creature to have ever walked the earth - a dinosaur measuring 130 feet and weighing 77 tonnes - has been discovered in Argentina, palaeontologists have said.

Its gigantic bones were found by a local farm worker in a desert in Patagonia, the southern Argentine region that has yielded many important dinosaur discoveries.

Based on the size of the thigh bones – taller than an average man – the dinosaur would have been 130 feet long and 65ft tall, scientists said.

Its calculated 77-tonne weight would have made it as heavy as 14 African elephants, beating the previous record holder, Argentinosaurus, by some seven tonnes.

 The palaeontologists say the find is thought to be a new species of titanosaur – a huge herbivore of the long-necked sauropod group that lived in the Late Cretaceous period.

The bones were initially discovered a year ago in the desert near La Flecha, about 135 miles west of the Patagonian town of Trelew, and were this week excavated by a team of palaeontologists from Argentina’s Museum of Palaeontology Egidio Feruglio, headed by Dr Jose Luis Carballido and Dr Diego Pol.

Scientists unearth unique, long-necked dinosaur in Argentina

They have retrieved some 150 bones said to come from seven individuals, all in “remarkable condition”.

“Given the size of these bones, which surpass any of the previously known giant animals, the new dinosaur is the largest animal known to have walked on Earth,” the researchers told BBC News.

“Its length, from its head to the tip of its tail, was 40 metres.

“Standing with its neck up, it was about 20 metres high – equal to a seven-storey building.”

The gargantuan dinosaur is said to have lived in the forests of Patagonia between 95 and 100 million years ago, based on the age of the rocks in which the bones were embedded.




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'Littlest giant' dinosaur found in Argentina

At 30 meters long, the newly discovered Leinkupal laticauda (shown here in Buenos Aires on Thursday, May 15) is not exactly small, but could also called the 'littlest giant.' Scientists in Argentina announced the discovery of the fossilized remains of this unique member of the famous long-necked, plant-munching dinosaurs known as sauropods, the largest land creatures in Earth's history. It lived about 140 million years ago.

Raptor Dinosaur Found In China

The nearly-complete skeleton of the birdlike dinosaur was found in inner Mongolia

A British scientist doing his PhD  discovered a dinosaur which had a huge claw and could run at more than 30mph while digging for fossils in the Gobi desert.

In this picture you see a cast of the skeleton of the new raptor dinosaur Linheraptor exquisitus discovered  with Michael Pittman, a graduate student at the University College of London, while hunting for fossils in red sandstone rocks in Inner Mongolia, a province in northern China.

Linheraptor was about six feet long, probably weighed around 50 pounds, and lived approximately 75 million years ago. Like most other dromaeosaurids (the scientific name for raptor dinosaurs), it has a large claw on the second toe of its foot and a tail stiffened by long bony rods that project from the vertebrae.

Linheraptor is important because it preserves almost every bone in the body. Scientists can get information from its skeleton that they can't get from the incomplete fossil skeletons of other dromaeosaurids.

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Gobi Desert of Inner Mongolia turns up evidence of a 90-million-year-old grave­yard

An expedition in the Gobi Desert of Inner Mongolia turns up evidence of a 90-million-year-old grave­yard, including the remains of more than a dozen fossilized ostrich like dinosaurs.
 

Professor Paul Sereno holds a plaque cast of two juvenile skeletons of the ostrich-mimic dinosaur Sinornithomimus that died when they were a little over one year in age. In their ribcages are stomach stones and the carbonized remains of their last plants they consumed. 


Evidence at the site points to a unique and rare conclusion: the dinosaur fossils were not deposited at the site over millennia. Instead the dinosaurs all met their fate at the same time.

The sudden death of the herd in a mud trap provides a rare snapshot of social behavior. Composed entirely of juveniles of a single species of ornithomimid dinosaur (Sinornithomimus dongi), the herd suggests that immature individuals were left to fend for themselves when adults were preoccupied with nesting or brooding.

Reader's Review

Really enjoying the book and found it difficult to put down. I rarely make that statement about a book. Haven’t dug into a fictional book like this since John Gresham’s “The Firm.” You’re a future John Gresham. I can’t even conceive of what must be involved with coming up with a story like this and getting it on paper in an interesting way.

Loved the first chapter. The detail was amazing when describing fish, locations, fly rods, etc. Pretty much everything about it grab my attention. I even found myself Googling locations wondering what was imagined and what was real. The mixture of real and fantasy makes a book so much fun as I think I may be actually learning something while enjoying the ride.

Love the short chapters. Much easier on me.

Loved the fast pace and vivid word pictures. I kept thinking this will be a great movie. Either you have a fabulous imagination which sells really well, done a ton of research to pull this book together with all the scientific classification of dinosaur type terms, or are one of the smartest guys in the world. Perhaps all three. In any event you are a great writer which I say about only a few. Every time you drop something in like a helicopter model number, drone price, who first said “survival of the fittest,” what inspired the “Halls of Montezuma,” I’m wondering how did you know all this stuff.

Awaiting your next book!

Dinosaur True Colors Revealed by Feather Find

First True-Color Dinosaur

Image courtesy Chuang Zhao and Lida Xing

Sinosauropteryx, a turkey-size carnivorous dinosaur, is the first dinosaur—excluding birds, which many paleontologists consider to be dinosaurs—to have its color scientifically established.

In 1996, Sinosauropteryx was also the first dinosaur reported to have feathers. It was found in the Yixian formation, 130- to 123-million-year-old sediments in Liaoning Province in northeast China, which have since produced thousands of apparently feathery fossils.

In a report released by the journal Nature, an international team of paleontologists and experts in scanning electron micrography infer that this dinosaur had reddish orange feathers running along its back and a striped tail.

Why would a dinosaur need a striped tail? Many birds, the living descendants of non-avian dinosaurs, use brightly colored tails for courtship displays.


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Tarbosaurus Gangs: What Do We Know?

The proposal of pack-hunting dinosaurs is old news in paleontological circles, and the hard evidence to support the claims about Tarbosaurus has not yet been released

Paleontologist Philip Currie poses with a tyrannosaur skull. Photo courtesy Atlantic Productions.

Tarbosaurus, the great tyrannosaur of Cretaceous Mongolia, hunted in packs. That is the exceptional claim made by University of Alberta paleontologist Philip Currie in a press release, and news outlets all over the world have picked up the story. Just imagine rapacious tyrannosaur families tearing over the prehistoric countryside; it is a terrifying notion that the press release heralds as a “groundbreaking” discovery that will forever change paleontology.

But does the actual evidence live up to all the hype? Unfortunately, the answer is no. The proposal of pack-hunting dinosaurs is old news in paleontological circles, and the hard evidence to support the claims about Tarbosaurus has not yet been released.

Packaged under the theme “Dino Gangs,” the media release, book, and cable-network documentary arranged by Atlantic Productions hinge on a Tarbosaurus bonebed found in Mongolia’s Gobi Desert. The site was one of 90 Tarbosaurus localities surveyed by Currie and the Korea-Mongolia International Dinosaur Project, but it is unique in that it preserves the remains of six individual animals of different life stages. How the animals died and became buried is unknown. Even so, the press claims that these dinosaurs were a single family group that hunted together.

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Moa Sightings

The legends of the Moa still surviving in New Zealand continued into the 20th century and as modern myth it is still well and alive until the last years. In 1993 the military officer Paddy Fearney and teacher Sam Waby claimed to have seen a large bird on the shores of a river in the interior of the Southern Island. After a first surprise Fearney managed to take a photo that was widely published in the January and February issues of various journals.

However the photo is very blurry and palaeontologists consider the photo showing only the posterior part of a deer. Also it would not be the first hoax in the history of the Moa – in 1954 the workman Neville perpetuated a hoax by applying false claws on his shoes and creating some Moa footprints.



Paddy was a former member of the British elite SAS squad and an avid mountaineer, and was not thought of by his peers as a publicity seeker.


His Story. “The three claim the creature stood three feet off the ground, had a thin long neck, roughly three feet long, ending in a small head and beak. The bird had reddish brown and grey feathers that covered the entire body with the exception of its legs from below the knees. Seeing the men the Moa fled across the river, Freaney gave chase and was able to take a photograph of the Moa at a distance of nearly 115 feet”.
The claim, because of who he was and because of the photo, meant the event was taken seriously at the highest levels of government. Many debunkers appeared and claimed Paddy’s sighting was nonsense and that the photograph was everything from a fake to a small red deer. Paddy was upset and outraged and spent many years trying to regain his good name by launching expeditions to find proof that the Moa was out there unfortunately to no avail.





Despite scientific wisdom denying any evidence that Moas lived past the 1500s, the legend of the still-roaming Moa, so central to the life of early Maori persist – Here are a couple of the more credible reports. 

1) In 1880, at Martins Bay, 30km north of Milford Sound, in Fiordland Alice McKenzie (Age 7) describes in her meticulous diary jottings of everyday life how she saw a large blue bird under flax where the bush line met the beach. Alice describs touching the bird’s curved rump feathers and stretching out one of its dark-green, scaly legs. It was only when Alice tried to tether the bird with flax that it let out a “harsh, grunting cry” and chased her for a short distance. McKenzie described the bird as being pukeko blue, with legs as thick as her wrist and no noticeable tail. When it stood up, it seemed as tall as she was

2) In 2008, Rex & Heather Gilroy, Cryptozoologists have claimed to have taken casts of Moa footprints from the Ureweras range (Remote North Island) and made other claims about their current-day existence. Gilroy claimed these proved the later-day presence of the smaller scrub Moas, measuring between 90 centimetres and about 1.5 meters.

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Feathered Dinosaurs: Moa

Joel Polack, a trader who lived on the East Coast of the North Island from 1834 to 1837, recorded in 1838 that he had been shown "several large fossil ossifications" found near Mt Hikurangi. He was certain that these were the bones of a species of emu or ostrich, noting that "the Natives add that in times long past they received the traditions that very large birds had existed, but the scarcity of animal food, as well as the easy method of entrapping them, has caused their extermination". Polack further noted that he had received reports from Māori that a "species of Struthio" still existed in remote parts of the South Island. Dieffenbach also refers to a fossil from the area near Mt Hikurangi, and surmises that it belongs to "a bird, now extinct, called Moa (or Movie) by the natives". In 1839 John W. Harris, a Poverty Bay flax trader who was a natural history enthusiast, was given a piece of unusual bone by a Māori who had found it in a river bank. He showed the 15 centimetres (6 in) fragment of bone to his uncle, John Rule, a Sydney surgeon, who sent it to Richard Owen, who at that time was working at the Hunterian Museum at the Royal College of Surgeons in London.

Owen puzzled over the fragment for almost four years. He established it was part of the femur of a big animal, but it was uncharacteristically light and honeycombed. Owen announced to a skeptical scientific community and the world that it was from a giant extinct bird like an ostrich, and named it Dinornis. His deduction was ridiculed in some quarters, but was proved correct with the subsequent discoveries of considerable quantities of moa bones throughout the country, sufficient to reconstruct skeletons of the birds.

In July 2004, the Natural History Museum in London placed on display the moa bone fragment Owen had first examined, to celebrate 200 years since his birth, and in memory of Owen as founder of the museum.

Sir Richard Owen holding the first discovered moa fossil and standing with a Dinornis skeleton

Preserved footprints of a D. robustus found in 1911

Since the discovery of the first moa bones in the late 1830s, thousands more have been found. They occur in a range of late Quaternary and Holocene sedimentary deposits, but are most common in three main types of site: caves, dunes, and swamps.  Approximately eight moa trackways, with fossilised moa footprint impressions in fluvial silts have been found.

Several remarkable examples of moa remains have been found which exhibit soft tissues (muscle, skin, feathers), that were preserved through desiccation when the bird died in a naturally dry site (for example, a cave with a constant dry breeze blowing through it).

 

Wacky Forms of Alternative Energy

Reprocessing Coffee Grounds into Biodiesel

 

That morning cup of Joe that helps fuel us for the day ahead could soon also help propel trucks as well. In 2009, University of Nevada-Reno engineering professor Mano Misra, known around the lab for his coffee consumption, noticed the sheen of oil floating on top of a cup of brew that had cooled. A light bulb went off in Misra's caffeinated brain, and he asked a couple of students to work on a project to investigate whether coffee oil could be a feedstock for biodiesel.

The students determined that, depending on the particular bean used in the brew, coffee grounds can contain as much as 20 percent oil, and that it has an unusually high oxidative stability (which means it won't break down when exposed to oxygen and therefore gunk up fuel lines). They subsequently developed a method to remove the sulfur found in coffee biodiesel, which comes from the volcanic soils in the mountainous regions where coffee generally is grown. The resulting fuel was sufficient to meet the standards set by ASTM International, an international testing organization, for biodiesel.

The researchers estimate that if all the waste grounds generated by the world's coffee drinkers were gathered and reprocessed, the yield would amount to 2.9 million gallons of diesel fuel each year. Alternatively, the coffee grounds could be converted to fuel pellets. If all of the leftover grounds from Starbucks were reprocessed, they would produce 89,000 tons of such fuel pellets annually, enough to generate millions of dollars in revenue for the coffee-shop chain, as well as help counter rising fuel costs for trucking companies [source: Schill].

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Inside China's Energy Machine

Opening the Shale Gas Valve

Photograph from Reuters

A  worker checks valves on a natural gas appraisal well at a China Petroleum & Chemical Corporation facility in Langzhong, Sichuan Province. The province holds some of China's largest stores of natural gas.

Also known as Sinopec, China Petroleum is one of the largest state-owned energy companies in China, and its gas pipelines span more than 2,825 miles (4,545 kilometers) across the country.

Last year, Sinopec reportedly produced nearly 17 percent more natural gas, and discovered more than 80 percent more natural gas reserves, than it did in 2010. But it's looking for growth beyond China. Sinopec bought a one-third stake in five exploratory shale gas fields in the United States last month as part of a $2.2 billion deal with Oklahoma City-based Devon Energy. Devon pioneered the horizontal drilling technology, combined with hydraulic fracturing, that has unlocked vast unanticipated stores of natural gas from shale formations across the United States. Such a deal gives Sinopec the opportunity to import the made-in-the-USA shale gas technology.

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Edward Hitchcock's fossil footprints

Footprints in New England, 1858 

 

Edward Hitchcock was professor of geology at Amherst College in Massachusetts when a colleague wrote him about a stone slab he had found that contained large footprints. Hitchcock was immediately intrigued, and within a year, in 1836, he published his first paper about the stone footprints of the Connecticut Valley. He published a number of further articles in the ensuing two decades, amassed quite a collection of footprint-bearing slabs for a museum at his college, and finally reviewed the entire field in this sumptuous study of 1858. Hitchcock called his new science "ichnology," a shortening of his original term, "ichnolithology."

The work has sixty lithographs, many of them mere line drawings of tracks, but with an equal number depicting the slabs themselves with almost photographic realism. By far the most charming plate is the first one, a chromolithograph that depicts the Moody Footmark Quarry in South Hadley. It shows the site where Pliny Moody had discovered the very first fossil tracks in 1802; Moody himself helped prepare the sketch from which this lithograph was made. We reproduce a detail of this large print.

We now know that nearly all of the prints that Hitchcock studied and collected were made by Triassic dinosaurs. Hitchcock, however, never entertained this idea, for good reason: the prints were made by large bipeds, and at the time, dinosaurs were thought to be quadrupedal. Hitchcock instead believed that these were the footprints of large birds. Ironically, in the very year of this publication, the first good evidence for bipedal dinosaurs was being discovered by Joseph Leidy in New Jersey.

This was Edward Hitchcock's first published article on the fossil footprints of the Connecticut River Valley. He said that his attention was first called to the subject by James Deane, who send him some casts of impressions. He was soon able to obtain the red sandstone slabs themselves, and these were deposited in the Amherst College cabinet, where they would soon be joined by samples from other localities. Hitchcock described most ot these samples in his article.

Included with the article was a folding plate with twenty-four figures of his collected tracks, which Hitchcock was convinced were made by birds. We show here a detail from this plate.


Source

Hitchcock, Edward. "Ornithichnology. Description of the Foot marks of Birds, (Ornithichnites) on new Red Sandstone in Massachusetts," in: American Journal of Science, vol. 29 (1836), pp. 307-340. This work is part of our History of Science Collection, but it was NOT included in the original exhibition.

Hitchcock’s Primeval Birds

Paleontologist Edward Hitchcock was one of the first dinosaur track experts, but why did he insist that birds left the footprints

Edward Hitchcock was one of America’s first dedicated dinosaur paleontologists. He just didn’t know it. In fact, during the latter part of his career, he explicitly denied the fact. To Hitchcock, the tracks skittering over red sandstone in the Connecticut Valley were the marks of prehistoric birds from when the Creation was new. Hitchcock could not be dissuaded. As new visions of dinosaurs and the notion of evolution threatened to topple his life’s work, the Amherst natural theologian remained as immutable as the fossil footprints he studied.

Hitchcock was not the first to wonder about the prehistoric imprints. Members of the Lenape, a Native American group in Canada and the northeastern United States, had seen the bizarre, three-toed tracks and ascribed them to monsters and other beings. These were the footsteps of creatures that ruled the world before humans came to dominance. European settlers and their descendants had to stretch their mythology a little more to accommodate the tracks. Some thought such tracks might have been left by Noah’s raven after the biblical deluge, although many simply called them “turkey tracks” and apparently were little concerned with where they had come from.

It wasn’t until 1835 that James Deane, a doctor with a curiosity for natural history, found out about a sample of the peculiar tracks near Greenfield, Massachusetts. He knew that they represented prehistoric organisms, but he wasn’t sure which ones. He wrote to Hitchcock, then a geology professor at Amherst, to inquire about what could have left such markings in stone. At first Hitchcock didn’t believe Deane. There might be some quirk of geological formation that could have created track-like marks. But Deane was persistent. Not only did he change Hitchcock’s mind, but the geologist became so enthusiastic that he quickly became the most prominent expert on the tracks—a fact that frustrated Deane and led to tussles in academic journals over who really was the rightful discoverer of the Connecticut Valley’s lost world.

Hitchcock began publishing about the peculiar trace fossils in 1836. He was confident from the very start that they must
have been created by prehistoric birds. (He was so enthused by the idea he even wrote poetry about the “sandstone birds.”) No variety of creature matched them better. The word “dinosaur” had not even been invented yet; the British anatomist Richard Owen would establish the term in 1842. The few dinosaurs that had been found, such as Iguanodon, Megalosaurus and Hylaeosaurus, were known only from paltry remains and all were believed to have been enormous variations of lizards and crocodiles. Dinosaurs were a poor fit for the tracks, and became even worse candidates when Owen gave them an anatomical overhaul. Owen not only named dinosaurs, he re-branded them as reptiles with mammal-like postures and proportions. The huge sculptures of the Crystal Palace exhibition, created with the help of artist Benjamin Waterhouse Hawkins, are a testament to Owen’s view of dinosaurs as reptiles that had taken on the anatomical attitudes of rhinoceros and elephants.

But Owen and other paleontologists did not agree with Hitchcock’s interpretation. They argued that the tracks could have been made by some unknown variety of amphibian or reptile. This was not so much because of the anatomy of the tracks—anyone could see that they were made by creatures with bird-like feet—but because no one thought that birds could have lived at so ancient a time or grown large enough to make the biggest, 18-inch tracks Hitchcock described. Even though early 19th century paleontologists recognized that life changed through the ages, they believed there was a comprehensible progression in which so-called “higher” types of creatures appeared later than others. (Mammals, for example, were thought to have only evolved after the “Secondary Era” when reptiles ruled since mammals were thought to be superior to mosasaurs, ichthyosaurs, and other creatures of that middle time.) 
Hitchcock remained steadfast, and his persistence was eventually rewarded with the discovery of the moa. These huge, flightless birds recently lived on New Zealand—they were wiped out more than 500 years ago by humans—and in 1839 Richard Owen rediscovered the birds through a moa thigh bone. He hypothesized that the bone must have belonged to a large, ostrich-like bird, and this idea was soon confirmed by additional skeletal bits and pieces. Some of these ratites stood over nine feet tall. When the news reached Hitchcock in 1843, he was thrilled. If recent birds could grow to such sizes, then prehistoric ones could have been just as large. (And, though Hitchcock died before their discovery, preserved moa tracks have a general resemblance to some of the largest footprints from the Connecticut Valley.) Opinion about the New England tracks quickly changed. There was no longer any reason to doubt Hitchcock’s hypothesis, and paleontologists hoped that moa-like bones might eventually be found to conclusively identify the trackmakers.

Lacking any better hypotheses, Hitchcock prominently featured his avian interpretation of the three-toed tracks in his 1858 book The Ichnology of New England. It was a gorgeous fossil catalog, but it also came at almost precisely the wrong time. Gideon Mantell, the British doctor and paleontologist who discovered Iguanodon, was beginning to wonder if some dinosaurs primarily walked on their hind limbs in a bird-like fashion, and the Philadelphia polymath Joseph Leidy described Hadrosaurus, a dinosaur certainly capable of bipedal locomotion on account of having shorter forelimbs than hindlimbs, the same year that Hitchcock’s monograph came out. Dinosaurs were undergoing another major overhaul, and the few that were known at the time were being recast as relatively bird-like creatures. Even worse for Hitchcock, the following year another student of the Connecticut Valley tracks, Roswell Field, reinterpreted many of the footprints and associated traces as being made by prehistoric reptiles. Especially damning was the fact that deep tracks, left when the creatures sunk into the mud, were sometimes associated with drag marks created by a tail. Hitchcock’s tableau of ancient Massachusetts moas was becoming increasingly unrealistic.

If Hitchcock ever doubted his interpretation, he never let on. He reaffirmed his conclusions and modified his arguments in an attempt to quell dissent. In his last book, A Supplement of the Ichnology of New England, published in 1865, a year after his death, Hitchcock used the recently discovered Jurassic bird Archaeopteryx as a way to save his interpretation. Tail drags were no obstacle to the bird hypothesis, Hitchcock argued, because Archaeopteryx was generally regarded as being the primordial bird despite having a long, reptile-like tail. Perhaps such a bird could have been responsible for the trace fossils Hitchcock called Anomoepus, but the tail drags left by the animals that dwelled in Jurassic New England were also associated with tracks indicating that their maker walked on all fours. In response, Hitchcock cast Archaeopteryx as a quadrupedal bird—a representative of a new category different from the classic, bipedal bird tracks he had promoted for so long.

Other paleontologists took a different view. If Archaeopteryx looked so primitive and lived after the time when the red Connecticut sandstone was formed, then it was unreasonable to think that more specialized, moa-like birds created Hitchcock’s tracks. Furthermore, a few bones found in a Massachusetts quarry of roughly the same age in 1855 turned out to belong to a dinosaur—a sauropodomorph that Othniel Charles Marsh would later name Anchisaurus. The bird bones never turned up, and all the while dinosaur fossils were becoming more and more avian in nature. By the 1870s the general paleontological opinion had changed. New England’s early Jurassic was not filled with archaic birds, but was instead home to dinosaurs which were the forerunners of the bird archetype.

Our recent realization that birds are the direct descendants of one group of coelurosaurian dinosaurs has led some of Hitchcock’s modern day fans to suggest that he was really right all along. In an essay for the Feathered Dragons volume, paleontologist Robert Bakker extolled Hitchcock’s scientific virtues and cast the geologist’s avian vision for the tracks as essentially correct. Writer Nancy Pick, in her 2006 biography of the paleontologist, wondered, “What if Hitchcock clung to his bird theory because he was right?” But I think such connections are tenuous—it is a mistake to judge Hitchcock’s work by what we have come to understand a century and a half later.


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The Extent of the Preserved Feathers on the Four-Winged Dinosaur Microraptor gui under Ultraviolet Light

Examination under ultraviolet light reveals that these feathers actually reach the body of the animal and were not disassociated from the bones. Instead they may have been chemically altered by the body tissues of the animal meaning that they did not carbonise close into the animal or more likely were covered by other decaying tissue, though evidence of their presence remains.

These UV images show that the feathers preserved on the slab are genuinely associated with the skeleton and that their arrangement and orientation is likely correct. The methods used here to reveal hidden features of the specimen may be applicable to other specimens from the fossil beds of Liaoning that produced Microraptor.

Figure 2: The holotype of Microraptor gui, IVPP V 13352 under UV light.

Different filters were employed for parts A and B, hence the difference in colour and appearance. A also is labeled to indicate the preserved feathers (grey arrows) and the ‘halo’ around the specimen where they appear to be absent (black arrows) as well as phosphatised tissues (white arrows). Scale bars are 5 cm in both A and B.

Figure 3: Close up of lower hindlimb of the holotype under UV light.

This shows that the feathers do indeed penetrate the halo (grey arrows) when seen in UV and approach or reach the bones. These are not seen in natural light due to the overlying soft tissues seen in figure 2. Scale bar at 5 cm.


Source: Plos One

Juravenator: Germany’s Other Feathered Dinosaur

The skeleton of Juravenator under UV light. If you look closely around the middle of the tail, you can see the traces of soft tissue. From Chiappe and Göhlich, 2010.

In 1861, as debates about evolution were brewing among naturalists, two important skeletons were discovered from the Late Jurassic limestone quarries of Germany. Both would be relevant to ideas about how birds evolved. Although not recognized as such until the late 20th century, Archaeopteryx was the first feathered dinosaur ever discovered and was a confirmation that birds had evolved from reptiles. The other creature, Compsognathus, represented a small, exceptionally bird-like dinosaur, and the anatomist T.H. Huxley took it as a proxy for the kind of animal from which birds originated. “There is no evidence that Compsognathus possessed feathers,” Huxley said during his 1877 American lecture tour, “but, if it did, it would be hard indeed to say whether it should be called a reptilian bird or an avian reptile.”

Now another feathered dinosaur has been discovered from the famous German limestone quarries. Named Juravenator starki in 2006, this dinosaur was a close relative of Compsognathus which lived just a little bit earlier on the same prehistoric archipelago. It is one of the most complete dinosaurs from these limestone deposits. From the tip of the snout to very nearly the end of the tail, the whole skeleton was preserved, but there was something special about this animal that could only be seen in the right light.

David Hone and colleagues published a paper showing how examining fossils under ultraviolet light can illuminate soft-tissue structures—like feathers—that would otherwise be hidden. Paleontologists Luis Chiappe and Ursula Göhlich applied the same technique to the Juravenator skeleton, and near the middle of the dinosaur’s tail they found an area of preserved soft tissue. The most easily seen parts of the soft tissue were patches of tiny bumps consistent with the skin impressions of other dinosaurs. Yet there were wispy protofeathers, too. Thanks to high-resolution photography, the remains of downy feathers were also detected, and these were similar to the structures that covered the body of a relative of Juravenator from China called Sinosauropteryx. 

Juravenator was a small bipedal predator. Size of the juvenile type specimen, with a human for scale - See more at: http://www.fossilriver-thenovel.com/#sthash.qRxbHFb9.dpuf

Juravenator was a small bipedal predator. Size of the juvenile type specimen, with a human for scale

The presence of both scaly skin and filamentous feathers makes Juravenator unique among feathered dinosaurs. This combination has not been seen before, but it is consistent with laboratory models of how feathers evolved from scaly skin. Furthermore, it appears that Juravenator was not wholly covered by a coat of fluffy feathers like baby chicks, perhaps indicating that feathery structures appeared on some parts of the bodies of dinosaurs before others. Frustratingly, the extent of soft-tissue preservation on the first Juravenator specimen is extremely limited, but further discoveries of this animal may help us better understand the origins of feathered dinosaurs.

Reposted from Smithsonian Magazine

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