Dinosaur age bird’s colour research


Eoconfuciusornis zhengi reconstruction

From Science News:

Cretaceous bird find holds new color clue

First evidence of pigment pods embedded in keratin found in fossil feathers

By Meghan Rosen

3:30pm, November 21, 2016

A 130-million-year-old bird holds a clue to ancient color that has never before been shown in a fossil.

Eoconfuciusornis’ feathers contain not only microscopic pigment pods called melanosomes, but also evidence of beta-keratin, a protein in the stringy matrix that surrounds melanosomes, Mary Schweitzer and colleagues report November 21 in the Proceedings of the National Academy of Sciences.

Together, these clues could strengthen the case for inferring color from dinosaur fossils, a subject of debate for years (SN: 11/26/16, p. 24). Schweitzer, a paleontologist at North Carolina State University in Raleigh, has long pointed out that the microscopic orbs that some scientists claim are melanosomes may actually be microbes. The two look similar, but they have some key differences. Microbes aren’t enmeshed in keratin, for one.

In Eoconfuciusornis’ feathers, Schweitzer and colleagues found round, 3-D structures visible with the aid of an electron microscope. And a molecular analysis revealed bundles of skinny fibers, like the filaments of beta-keratin in modern feathers. The authors don’t speculate on the bird’s color, but they do offer a new way to support claims for ancient pigments.

“Identifying keratin is key to ruling out a microbial source for microbodies identified in fossils,” they write.

Oviraptor dinosaur discovery in China


This video from China ays about itself:

10 November 2016

A newly discovered species of dinosaur has been identified from an extraordinarily complete fossil almost destroyed by dynamite.

Preserved raising its beaked head, with feathered wings outstretched, in the mud it was mired in when it died 72 million years ago, it was one of the last surviving dinosaurs in Asia.

From Science News:

Dragon dinosaur met a muddy end

Feathered oviraptorosaurs surged at the end of the age of dinosaurs

By Meghan Rosen

9:00am, November 10, 2016

A bizarre new birdlike dino was part of an evolutionary extravaganza at the end of the age of dinosaurs. And it was a real stick-in-the-mud, too.

Construction workers blasted Tongtianlong limosus out of the Earth near Ganzhou in southern China. “They very nearly blew this thing to smithereens,” says paleontologist Stephen Brusatte of the University of Edinburgh in Scotland.

The find is one of six oviraptorosaur species discovered from roughly the same place and time — around 72 million to 66 million years ago. Like its feathered cousins, Tongtianlong walked on two legs and had a sharp beak. But each species had distinct skeletal quirks.

Tongtianlong, for one, had a bony, domelike crest on its skull. Oviraptorosaurs were churning out lots of new species during the last stage of the Cretaceous Period, Brusatte says. Tongtianlong was part of “the final wave of dinosaur diversification before the asteroid came down and ended everything.”

This particular fossilized animal lies in a bed of reddish-purple mudstone, preserved in an unusually awkward position: head stuck out, neck arched, wings outspread. It may have died after a desperate struggle to free itself from mud, researchers suggest November 10 in Scientific Reports. That’s actually how the dinosaur gets its name: Tongtianlong limosus is a mix of Chinese Pinyin and Latin meaning “muddy dragon on the road to heaven.”

Valdosaurus dinosaur, well-preserved fossil found in England


This video says about itself:

2 September 2015

Dryosaurus” is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont. Fossils have been found in the western United States, and were first discovered in the late 19th century. “Valdosaurus canaliculatus” and “Dysalotosaurus lettowvorbecki” were both formerly considered to represent species of “Dryosaurus”.

“Dryosaurus” had a long neck, long, slender legs and a long, stiff tail. Its arms, however, with five fingers on each hand, were short. Known specimens were about 8 to 14 feet long and weighed 170 to 200 pounds. However, the adult size is unknown, as no known adult specimens of the genus have been found.

“Dryosaurus” had a horny beak and cheek teeth and, like other ornithopods, was a herbivore. Some scientists suggest that it had cheek-like structures to prevent the loss of food while the animal processed it in the mouth.

A quick and agile runner with strong legs, “Dryosaurus” used its stiff tail as a counterbalance. It probably relied on its speed as a main defense against carnivorous dinosaurs.

The teeth of “Dryosaurus” were, according to museum curator John Foster, characterized by “a strong median ridge on the lateral surface.” “Dryosaurus” subsisted primarily on low growing vegetation in ancient floodplains.

A “Dryosaurus” hatchling found at Dinosaur National Monument in Utah confirmed that “Dryosaurus” followed similar patterns of craniofacial development to other vertebrates; the eyes were proportionally large while young and the muzzle proportionally short. As the animal grew, its eyes became proportionally smaller and its snout proportionally longer.

By Pete Buchholz in Britain:

A specimen of the dryosaurid Valdosaurus has been discovered on the Isle of Wight

The most complete specimen of the poorly known dryosaurid Valdosaurus canaliculatus has been discovered in Lower Cretaceous rocks on the Isle of Wight. This new discovery helps flesh out the anatomy of this dinosaur and is one of the most complete dinosaur specimens known from England.

The Isle of Wight off the south coast of England is a fossil-hunter’s paradise. Rocks of the Wessex Formation, deposited during the Early Cretaceous, approximately 130 million years ago, are exposed in numerous locations across the island. The Wessex Formation preserves numerous fish, turtles, crocodilians, and pterosaurs. It also has a rather famous dinosaur fauna, including the spinosaurid Baryonyx, the early tyrannosaur Eotyrannus, a number of fragmentary sauropods, and the ornithopods Iguanodon, Mantellisaurus, Hypsilophodon, and Valdosaurus.

Noisy dinosaur age bird discovered in Antarctic


This video says about itself:

Discovery of fossil “voice box” of Antarctic bird suggests dinosaurs couldn’t sing

2 October 2016

Researchers have found the oldest known fossil vocal organ of a bird … in Antarctica. The voice box is from a species related to ducks and geese that lived during the age of dinosaurs more than 66 million years ago. A National Science Foundation funded team led by the University of Texas at Austin discovered the ancient vocal organ called a syrinx–and its apparent absence from non-bird dinosaur fossils of the same age. Researchers believe the organ may have originated late in the evolution of birds after the origin of flight. Drawing on their research, team leader Julia Clarke said that other dinosaurs may not have been able to make noises similar to modern bird calls, but most likely made closed-mouth sounds similar to ostrich booms that don’t require a syrinx.

The organ was found in a fossil species called Vegavis iaai. The fossil was discovered in 1992 on Vega Island in the Antarctic Peninsula by a team from the Argentine Antarctic Institute. It was named in 2005 by Clarke and Argentine colleagues. But, it wasn’t until 2013 Clarke discovered the fossil syrinx in the new specimen and began analysis. The international team may figure out what dinosaurs sounded like, gaining insight into the origins of bird song. The findings appear in the October 12 issue of “Nature”.

See also here.

From Science News:

Birds’ honks filled Late Cretaceous air

Sounds inferred from oldest preserved avian voice box

By Meghan Rosen

3:53pm, October 12, 2016

ANCIENT VOICE BOX: A ducklike bird that lived some 68 million to 66 million years ago left behind fossilized remains of a voice box, or syrinx, on an island off the coast of Antarctica.

Some ancient birds may have sounded like honking ducks.

For the first time, scientists have discovered the fossilized remains of a voice box from the age of the dinosaurs. The sound-making structure, called a syrinx, belonged to Vegavis iaai, a bird that lived 68 million to 66 million years ago, researchers report October 12 in Nature.

“It may be a once-in-a-lifetime discovery,” says evolutionary biologist Patrick O’Connor of Ohio University in Athens, who wrote a commentary in Nature about the fossil. Now, he says, the hunt will be on to find voice boxes in other fossils.

The new work helps fill in the soundscape of the Late Cretaceous Epoch. It could also offer hints about sounds made by all sorts of dinosaurs, says study coauthor Julia Clarke of the University of Texas at Austin.

Unlike in humans, where the larynx lies below the throat, birds’ voice boxes rest inside the chest at the base of the windpipe. Stacked rings of cartilage anchor vibrating membranes that make sound when air whooshes through.

This delicate structure doesn’t typically fossilize. In fact, scientists have previously spotted just a few syrinxes in the fossil record. The oldest known, from a wading bird, was about 50 million years old. Clarke’s team examined that syrinx, which hadn’t been studied before, and the one from V. iaai.

The V. iaai fossil, a partial skeleton discovered on an island off the coast of Antarctica, was removed from a rock about the size of a cantaloupe, Clarke says. Just one small area remained encased in rocky material. Everyone thought that bit was trivial, she says. But “it was within that tiny little section that I saw the syrinx.” Three-dimensional CT scans let her peer within the rock and see the telltale rings of a voice box, a structure roughly half the size of a multivitamin pill. “It was one of the biggest, happiest days of my career,” Clarke says.

Biologist Philip Senter of Fayetteville State University in North Carolina, who was not involved in the study, echoes Clarke’s enthusiasm. “It’s quite exciting to find such a rarely preserved structure,” he says. Seeing it in 3-D will make paleontologists “chortle joyously.”

Comparing the fossil with living birds helped Clarke and her team figure out what sounds the ancient bird might have made. Both the bird’s skeleton and its syrinx suggest it squawked like today’s ducks and geese.

The find also proves that voice boxes from dinosaurs’ time can indeed fossilize. No one has found the structures in nonavian dinosaurs, Clarke says. “That suggests that most dinosaurs may not have had a syrinx.”

Instead, she proposes, dinosaurs like Tyrannosaurus rex and Stegosaurus might have made noises like crocodiles: deep “booming” sounds generated in the back of the mouth.

Small Cretaceous pterosaurs discovered


This video says about itself:

25 July 2014

Pterosaurs (/ˈtɛrɵsɔr/, from the Greek πτερόσαυρος, pterosauros, meaning “winged lizard”) were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period (228 to 66 million years ago).

Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger. Early species had long, fully toothed jaws and long tails, while later forms had a highly reduced tail, and some lacked teeth. Many sported furry coats made up of hair-like filaments known as pycnofibers, which covered their bodies and parts of their wings. Pterosaurs spanned a wide range of adult sizes, from the very small Nemicolopterus to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx.

From Science News:

Pterosaurs weren’t all super-sized in the Late Cretaceous

Some of the flying reptiles were smaller than a bald eagle

By Meghan Rosen

7:00am, September 12, 2016

Pterosaurs didn’t have to be gargantuan to survive in the Late Cretaceous.

Fragmentary fossils of a roughly 77-million-year-old pterosaur found in British Columbia suggest it had a wingspan of just 1.5 meters, about a quarter that of a bald eagle.

Bald eagles have wingspans of about two meters. So, the newly discovered pterosaus were smaller than bald eagles; but not four times smaller.

The ancient flier is the smallest pterosaur discovered during this time period — by a lot, report paleontologist Elizabeth Martin-Silverstone of the University of Southampton in England and colleagues August 30 in Royal Society Open Science.

Dozens of larger pterosaurs, some with wings spanning more than 10 meters (nearly the length of a school bus), have been unearthed. But until now, scientists had found only two small-scale versions, with wingspans 2.5 to 3 meters long, from the period stretching from 66 million to 100 million years ago.

Some scientists blamed competition with birds for the scarcity of little flying reptiles. Researchers have proposed that, “the only way pterosaurs could survive was by evolving completely crazy massive sizes,” Martin-Silverstone says.

The new find, she says, may mean that, “pterosaurs were doing better than we thought.”

Unusual carnivorous dinosaur described


This video says about itself:

13 July 2016

A newly discovered meat-eating dinosaur that prowled Argentina 90 million years ago would have had a hard time using strong-arm tactics against its prey. That’s because the beast, though a fearsome hunter, possessed a pitifully puny pair of arms.

Scientists said on Wednesday they have unearthed fossils in northern Patagonia of a two-legged, up to 26-foot-long (8-meters-long) predator called Gualicho shinyae with arms only about 2 feet (60 cm) long, akin to a human child’s.

The fossils of Gualicho, named after an evil spirit feared by Patagonia’s indigenous Tehuelche people, were discovered in Argentina’s Rio Negro Province.

Gualicho and other carnivorous dinosaurs like Tyrannosaurus rex are part of a group called theropods that included Earth’s largest-ever land predators. But a curious thing happened during their many millions of years of evolution. For some, as they acquired huge body size and massive skulls, their arms and their number of fingers shrank.

From the Christian Science Monitor in the USA:

T. rex wasn’t the only one with those strange little arms

Paleontologists discover a new dinosaur with T. rex-like arms, but it’s not a tyrannosaur.

By Eva Botkin-Kowacki, Staff writer

July 13, 2016

Quick! Make like a T. rex.

What is the first step to mimicking the famous, fearsome dinosaur? After roaring, a person probably pulls both arms in, contorting them to make them tiny relative to the rest of the body, mashing the five fingers together to have just two digits on each hand. One of the most characteristic features of the iconic tyrant lizard dinosaur is its strange, seemingly uselessly small forelimbs.

But Tyrannosaurus rex wasn’t the only two-legged carnivorous dinosaur to sport such teeny, two-fingered arms.

“Theropods in general do this quite often,” Lindsay Zanno, head of the Paleontology Research Lab at the North Carolina Museum of Natural Sciences, tells The Christian Science Monitor in a phone interview. “There are a lot of different groups of theropods that tend to reduce the size of their hands and their arms or change the way that they’re used.”

And another one is joining the bunch.

Gualicho shinyae, discovered in Argentina in 2007, is named and described in a paper published Wednesday in the journal PLOS ONE.

This new dinosaur’s “arms are short – about 2 ft long – which is less than the length of the thigh bone, and they have weak muscle attachments and poorly developed articulations indicating they had little strength,” Peter Makovicky, associate curator of dinosaurs at the Field Museum of Natural History in Chicago who co-led the team that discovered Gualicho, describes in an email to the Monitor.

The fingers on the 90-million-year-old fossil are similar to those of tyrannosaurs. The thumb has a large claw while the second finger is more slender. A third finger has become so reduced that it is just a tiny bone in the flesh of the animal’s hand. …

Gualicho has weak little arms with just two functional fingers like T. rex, but the similarities pretty much stop there.

“This animal has a kind of mosaic of features. There are aspects of its skeleton that show some affinities with some groups of dinosaurs and some affinities with other groups of dinosaurs, although none of those are really tyrannosaurs,” study co-author Nathan Smith, associate curator in the Dinosaur Institute at the Natural History Museum of Los Angeles County, tells the Monitor in a phone interview.

But the “oddball” dinosaur, as Dr. Smith describes it, could help researchers figure out why so many diverse theropod dinosaurs have evolved similar, reduced forelimbs. …

Some scientists have suggested that humongous predatory dinosaurs would have evolved smaller arms because their skulls were used more readily to wrangle prey, she says.

There seems to be a pattern among tyrannosaurs, for example, in which the arms became shorter and the fingers fewer as the animals’ skulls and bodies became larger over generations, says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not part of the study, in an email to the Monitor. This would suggest that “the head was taking over many of the duties that the arms once had, like procuring and processing food.”

“Most theropods with reduced forelimbs, like tyrannosaurs, ceratosaurs, and carcharodontosaurs are clearly macropredators that rely on their massive skulls for hunting, so it seems likely that the same was true of Gualicho,” Makovicky says.

These diverse dinosaurs were likely under similar evolutionary pressures that lead to similarly reduced forelimbs. The feature would have evolved independently in the different groups, in a process called convergent evolution. …

The mosaic features of Gualicho “makes figuring out the evolutionary placement of this animal a little difficult,” Smith says.

Weighing an estimated 1,000 pounds, Gualicho appears to fit into the family neovenatoridae, a large-bodied branch of carnivorous theropod dinosaurs, Smith says, but it also seems to bear the closest resemblance to Deltadromeus, a large theropod from Africa.

But could a South American dinosaur be closely related to an African one?

Possibly. Scientists have previously noted a lot of similarities between dinosaurs unearthed in the Kem Kem Beds on the border of Morocco and Algeria, where Deltadromeus has been found, and the Huincul Formation in Argentina, where Guialicho was discovered, Smith says. “So it may not be surprising that these two carnivorous dinosaurs are close relatives.”

And at the time when Guialicho roamed the Earth, the two continents had only recently, geologically speaking, begun to separate as the supercontinent Gondwana broke up.

‘Meteorite killed not only dinosaurs, also most mammals’


This video says about itself:

The Day the Mesozoic Died: The Asteroid That Killed the DinosaursHHMI BioInteractive Video

26 August 2014

Ever wonder why the dinosaurs disappeared? HHMI BioInteractive investigates the cause of the mass extinction at the end of the Cretaceous period—and the clues come from paleontology, chemistry, physics, and biology.

This three-act film tells the story of the extraordinary detective work that solved one of the greatest scientific mysteries of all time. Explore the fossil evidence of these prehistoric animals, and other organisms that went extinct, through this lively educational video.

From daily The Independent in Britain today:

Prehistoric asteroid wiped out nearly all mammals as well as dinosaurs, research suggests

‘More data shows the extinction was more severe than previously believed’

Jack Hardy

Nearly every species of mammal was eradicated by the prehistoric asteroid which wiped out the dinosaurs, research suggests.

Around 93% of mammal species were made extinct by the strike, which took place in the Cretaceous period, more than 66 million years ago.

Examination of fossil records by scientists from the University of Bath determined that the asteroid’s impact had been much more severe than previously thought.

Past estimates have been much lower because some of the rarer species that were killed left a smaller fossil record, researchers said.

The University of Bath’s Dr Nick Longrich said: “The species that are most vulnerable to extinction are the rare ones, and because they are rare, their fossils are less likely to be found.

“The species that tend to survive are more common, so we tend to find them.

“The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed.”

It was also found the asteroid’s catastrophic effect for life on Earth was mitigated by species recovering rapidly.

Within 300,000 years, the number of species on the planet was double the amount that had existed before the mass extinction.

Due to the lack of sustenance resulting from the widespread destruction of vegetation and animals, it is thought that the largest living animal during the period would have been about the size of a cat.

Dr Longrich added: “Because mammals did so well after the extinction, we have tended to assume that it didn’t hit them as hard.

“However, our analysis shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath.

“It wasn’t low extinction rates, but the ability to recover and adapt in the aftermath that led the mammals to take over.”

Researchers analysed all known mammal species in North America from the end of the Cretaceous period to draw their conclusions.

The findings were published in the Journal of Evolutionary Biology.