Stories tagged ancient birds
The fossil remains of a giant five-foot penguin has been unearthed in Paracas National Reserve, a desert region along the coast of Peru. The new species, named Inkayacu paracasensisI (water king), grew to a size nearly twice as large as the modern day Emperor penguin. The nearly complete fossil even skeleton included flippers and feathers. Some color of a bird's feathers can be deduced by the size of the melanosomes in its structure and by their shape and arrangement. When Inkayacu's melanosomes were compared with those of modern day birds, the nanostructures indicated that the giant penguin's feathers were reddish brown in color.
"Before this fossil, we had no evidence about the feathers, colors and flipper shapes of ancient penguins," said paleontologist Julia Clarke, of the University of Texas, and lead author of the report that appears in Science. The new evidence brings up new questions. For example, Clarke and her team aren't sure when or why the feather colors of most modern penguins shifted to black and white. I. paracenensis lived during the Eocene epoch 36 million years ago, and its fossil has been nicknamed Pedro.
SOURCES and LINKS
Science News
e! Science News
Story at redOrbit
Color in fossil feathers
Tags : 
Rex in the hen houseCourtesy Mark RyanA new study came out last week that appeared destined to shake up the current line of thought that birds descended from dinosaurs. Birds share common traits with some dinosaurs, including furculas (wishbones), hollow bones, and other skeletal features, which scientists have interpreted to mean the former descended from the latter. But now a new study by researchers at Oregon State University, it may have happened just the opposite way.
"We think the evidence is finally showing that these animals which are usually considered dinosaurs were actually descended from birds, not the other way around," said John Ruben, a professor of zoology at OSU, and the study’s lead author.
The study involved the fossil of a Microraptor, a dromaeosaurid dinosaur with evidence of feathers on both its arms and legs. Studying the skeletal remains, Ruben and his colleagues constructed 3-dimensional models that they tested for flight capabilities. Their study showed Microraptor’s structure better suited to be glider rather than a flyer. From this Ruben extrapolated that it made more sense that Microraptor descendents came down from the trees and eventually evolved into flightless birds we call dromaeosaurs or raptors.
"Raptors look quite a bit like dinosaurs but they have much more in common with birds than they do with other theropod dinosaurs such as Tyrannosaurus," he said. The study appears in the journal for the Proceedings of the National Academy of Science (PNAS).
Sounds good at first, and I have to admit I was smitten with the idea. But not everyone feels the same way.
Over at the Smithsonian’s Dinosaur Tracking blog, freelance science writer Brian Switek has pointed out that Ruben’s proclamation is “actually only a commentary, or the equivalent of an opinion piece.”
He then goes on to point out some of the flaws in Ruben’s argument, particularly the uncertainty surrounding Microraptor’s place in the evolution of flight, and the lack of reasonable evidence that Velociraptor wasn’t a dinosaur. Switek doesn’t think Ruben’s claim stands up to scrutiny.
But what annoys Switek most is how the media inundates the various outlets with this kind of science news, giving it wide distribution and often, undeserved credibility.
“In this increasingly fragmented media landscape, knowledgeable science writers who recognize a fishy story when they see one are getting outnumbered. More often, websites and newspapers simply reprint press releases issued by universities and museums (science writers call this “churnalism”), and this policy sometimes lets questionable science slip through the cracks.” – Brian Switek
One of the reasons for this is the internet. There's just a huge amount of time and space that requires constant feedings of content now. It does make things difficult to sort through. There have been times I’ve begun researching some new science story to post on Science Buzz only to become frustrated with details that don’t seem to add up, confusing statements, info that counters other info, and outright misinformation. Some of it may be due to the writer(s) not being able to properly articulate or distill a particular idea or hypothesis for the general reader (I know I suffer from this occasionally). Sometimes it’s due to the fact that many science writers lack access to the papers themselves (most science journals require paid subscriptions to access anything beyond an abstract of the story), so writers are left with relying on press releases and abstracts or another writer’s thoughts on the subject (like I’m doing here). But other times it ends up being that there’s no real story at all, just a rehash of something from months or years ago that somebody figures needed to be in the headlines again.
To this end, paleontologist Dave Hone over at his Archosaur Musings blog recently posted “A guide for journalists reporting on dinosaur stories” that deals with some of issues raised here. It’s worth reading.
Science Buzz has also covered science writing issues in previous posts.
How to read/write science news
Bad Science Journalism
SOURCE and MORE INFO
ScienceDaily.com story
Microraptor gui: Bird or Dinosaur
Origin and Evolution of Birds
Archaeopteryx: Detail of the Thermopolis SpecimenCourtesy Mark RyanWhen the first Archaeopteryx skeleton came to light in 1861 just two years after the publication of Charles Darwin’s On the Origin of Species, it was hailed as not only the earliest known bird but also as proof of evolution. The rare specimen (known as the London specimen) appeared to be somewhat of a chimera of both dinosaurian and bird features. Thomas Huxley, a fierce proponent of Darwin’s work, even suggested that birds were the descendents of small meat-eating dinosaurs. It took more than a century for the idea to become widely accepted. Today most paleontologists divide dinosaurs into two groups: avian dinosaurs (birds) and non-avian dinosaurs, the branch that died out at the end of the Cretaceous.
"For a long time, Archaeopteryx was considered the archetypical bird primarily because it had feathers, although it retained typical dinosaur features like a long tail and teeth,” said Mark Norell, Chair of the Division of Paleontology at the American Museum of Natural History. “But the discovery of classical bird features like feathers and wishbones have recently been found in many non-avian dinosaurs blurring the line of what constitutes a bird."
Now, a new study by Norell and co-author Gregory Erickson, a vertebrate paleontologist at Florida State University, shows that 150 million year-old Archaeopteryx (Greek for “ancient wing”) may have been much more like a non-avian dinosaur than a bird (avian dinosaur), at least in its bone structure and growth rate.
"Dinosaurs had a very different metabolism from today's birds,” Erickson said. “It would take years for individuals to mature, and we found evidence for this same pattern in Archaeopteryx and its closest relatives.”
For their research, the team removed tiny, 250-micron slivers of bone from the remains of several Archaeopteryx fossils, and from the bones of primitive but younger bird fossils (Jeholornis prima and Sapeornis chaochengensi, and Confuciornis sanctus) found recently in China. They also examined the bone structure of closely related non-avian dinosaurs such as Velociraptor mongoliensis.
Those samples from the Archaeopteryxes showed high bone-density, annual growth lines (a reptilian trait), and very small blood vessels similar to the bones sampled from the non-avian dinosaurs. The location of bone cells also appeared flattened and parallel – more like that of a velociraptor – and much different from the hollow, vascularized (i.e. filled with blood vessels), rapid growing bones found in younger-aged bird fossils, and most birds today. (Flightless birds such as ostriches and penguins have solid bones.)
"Although the genealogy of birds is well understood, the genesis of modern bird biology has been a huge mystery,” Norell said. “We knew that they are a kind of dinosaur, but we now know that the transition into true birds—physiologically and metabolically—happened well after Archaeopteryx."
What this implies is that Archaeopteryx was more of a dinosaur than it was a bird – at least in its metabolism and how fast it matured – and that the traits considered necessary for flight – such as light, hollow bone structure – evolved from a dinosaur body-plan sometime after Archaeopteryx.
"We show that avian flight was achieved with the physiology of a dinosaur," Erickson said.
The study can be found in a recent edition of the online journal PLoS ONE.
ScienceDaily story
Gregory Erickson’s Dinosaur Growth page
More info and photos about Archaeopteryx
Archaeopteryx: Its claim of having the first feathers may be over.Courtesy Mark RyanRecently discovered fossils out of China add strong evidence to the theory that birds descended from dinosaurs. The fossil remains of a new feathered dinosaur, named Anchiornis huxleyi, were discovered in rock strata thought to be at least 10 million years older than that at Solnhofen, Germany. This is exciting news. Since the 19th century the quarries at Solnhofen have produced several skeletons of the feathered Archaeopteryx which has long been considered the first bird. But now it appears that feathers arose several millions of years before Archaeopteryx showed up in the fossil record. Professor Xu Xing of Chinese Academy of Science in Beijing reported his findings in the science journal Nature, and at the Society of Vertebrate Paleontology's annual convention being held this week at the University of Bristol in England.
More about Archaeopteryx
More about the bird-dinosaur connection
Signs of color preserved in stone?: Fossil feather from Brazil (left) displays similarities with recent woodpecker feather (right)Courtesy J.Vinther/YaleResearchers at Yale University are reporting the discovery of pigmentation within the fossilize feather from a bird or dinosaur. Using a powerful electron microscope, paleobiologist Jakob Vinther and his team claim that particles seen in the 100-million-year-old fossil appear to be similar to those seen in the feathers of living birds. This could mean that color - a characteristic long-thought lost in the fossil record - could someday be determined from the remains of pigment.
Vinther’s colleagues included Yale paleontologist Derek E. G. Briggs and Yale ornithologist Richard O. Prum. The results of their study will appear in an upcoming issue of Biology Letters. The research shows that dark stripes in the Cretaceous-aged feather display many similarities to the make-up of black melanin particles found in modern bird feathers. Melanin compounds determine color in plants and animals, a trait useful for such things as camouflage, species identification, and courtship display. In humans, melanin colors our skin and also protects us from overexposure to sunlight.
For a long time, the dark granules seen in fossilized feathers were thought to be the carbon remains of bacteria that had worked at decomposing the organism prior to fossilization. But advances in electron microscope technology have given scientists a closer - and clearer – picture of the feather’s structure, and instead show them to be fossilized melanosomes containing melanin pigment.
"Feather melanin is responsible for rusty-red to jet-black colors and a regular ordering of melanin even produces glossy iridescence,” Vinther said. “Understanding these organic remains in fossil feathers also demonstrates that melanin can resist decay for millions of years."
Under the scope, the lighter bands of the fossilized feather showed only the rock matrix, while the darker bands displayed traces of residue closely resembling the organic compounds found in the feathers of modern birds.
“You wouldn’t expect bacteria to be aligned according to the orientation of the feathers,” said Vinther.
Another bird fossil showed similar organic traces in the feathers surrounding its skull. The 55-million-year-old fossil from Denmark also preserved an organic imprint of the eye that showed structures similar to the melanosomes found in eyes of modern birds.
Nanostructure studies could one day provide paleontologists with evidence of colors other than just black and gray tones, and not just in fossil feathers. Vinther figures other organic remains such as fur from prehistoric mammals or fossil skin impressions from dinosaurs could prove to be the remains of the melanin.
LINKS
ScienceNews story
Yale website story
Cosmos magazine website story
Melansome info
