Posts Tagged ‘Paleontology’

Giant dinosaur unearthed in Argentina

September 5, 2014

They just keep getting bigger. The latest dinosaur to be discovered was 26 metres long and seven times as heavy as Tyrannosaurus rex . Named Dreadnoughtus schrani by the team who found it, the bones belonged to the largest known land animal whose size can be reliably calculated. And it wasn’t even fully grown.

Dreadnoughtus schrani

The 77-million-year-old Dreadnoughtus skeleton was found in south-west Patagonia, Argentina, in 2005, and has taken several years to analyse. While other giants from Patagonia are known from a handful of bones, almost half of the Dreadnoughtus skeleton has been recovered. What’s more, the fossilised bones are in such good condition – even revealing where muscles attached – that the skeleton could provide unprecedented insights into the biology, movement and evolution of the group of huge plant-eating dinosaurs it belonged to, called the titanosaurian sauropods. Learn more here, here, here, here or here.

Dinosaurs were neither warm nor cold blooded

June 17, 2014

Depending on the source of an organism’s body warmth, it may be classified as either an ectotherm or an endotherm. An ectotherm is an animal that warms itself primarily by obtaining heat from the environment, perhaps by sunning itself. Ectothermic animals include most fish, amphibians, and reptiles as well as most invertebrates. An endotherm is an animal that produces most of its own heat and maintains a constant body temperature even when environmental temperatures fluctuate. All birds and mammals are endotherms.

Paleontologists have struggled for years to determine whether dinosaurs were cold-blooded like today’s reptiles or warm-blooded like most modern mammals and birds.

It turns out the answer is neither. Scientists have found evidence for “mesothermy” in dinosaurs. The “mesothermy” found in dinosaurs likely allowed them to move quickly, given that they would not need to constantly eat in order to maintain their body temperature (as do endotherms). As well, the dinosaur’s mesothermic metabolic rate would have decreased the vulnerability of these species to extreme fluctuations in external temperature, allowing them to exert some control of body temperature via internal mechanisms.

Dinosaur Mesotherm

Learn more here, here or here.

Blood found in fossilised mosquito for the first time ever

October 25, 2013

The premise of the movie Jurassic Park is that dinosaur DNA was available to clone from blood that a mosquito had ingested before it was trapped in amber. From the movie, you’d think that such mosquitoes were found all the time, enough so that several species of dinosaur could be resurrected. But at the time the movie was made, a blood-engorged mosquito in amber had never been found. However, we now have the next best thing.

About 30 years ago, Kurt Constenius, then a graduate student at the University of Arizona, collected hundreds of insect fossils in Montana and stored them in his parents’ basement. Retired biochemist Dale Greenwalt has been collecting fossils for the Smithsonian Museum of Natural History, and the Constenius family decided to donate all those fossils in the basement. Greenwalt noticed that one particular mosquito preserved in shale (not amber) was different.

Blood-engorged-mosquito

Staff from the museum’s mineral sciences lab used a number of techniques to scan the specimen up close, including energy dispersive X-ray spectroscopy. The first thing they found is that the abdomen was just chock full of iron, which is what you’d expect from blood. Additionally, analysis using a secondary ion mass spectrometer revealed the presence of heme, the compound that give red blood cells their distinctive color and allows them to carry oxygen throughout the body. Other tests showed an absence of these compounds elsewhere in the fossil.

The findings serve as definitive evidence that blood was preserved inside the insect. But at this point, scientists have no way of knowing what creature’s fossilized blood fills the mosquito’s abdomen. That’s because DNA degrades way too quickly to possibly survive 46 million years of being trapped in stone (or in amber, for that matter). Recent research had found it has a half-life of roughly 521 years, even under ideal conditions. Learn more here.

How to eat a Triceratops

December 24, 2012

If you’ve always wondered how Tyrannosaurs Rex ate the horned monstrosity that was a Triceratops, you need puzzle no longer. Scientists have finally pieced together how they did it — and it was surprisingly straightforward.

Scientists analysed a heap of bite-scarred Triceratops bones to come up with the new theory, which explains how T. Rex went about devouring the dinosaur. They’ve established four major steps:

1. Get a good grip on the neck frill.
2. Tear the head off to expose the tasty neck muscles.
3. Nibble on the soft flesh of Triceratops’ face.
4. Feast on the delicacies beneath the frill.

Learn more here.

Fossils confirm three early humans roamed Africa

December 9, 2012

After 40 years of searching, researchers can finally put a new face on a mysterious human ancestor whose skull was discovered 40 years ago in Kenya. The find is giving scientists a better look at a species that was alive soon after the dawn of our genus Homo about 2 million years ago. It also shows that there were several species of Homo present 1.78 million to 2.03 million years ago in the Rift Valley of Africa, and that they probably had to adapt in different ways to coexist.

Learn more here, here, here or here.

Extinction killed off some 90 percent of species

November 16, 2012

Extinctions during the early Triassic period left Earth a virtual wasteland, largely because life literally couldn’t take the heat, a new study suggests.

Between 247 to 252 million years ago, Earth was reeling from a mass extinction called the end-Permian event. The die-off had wiped out most life on Earth, including most land plants. The planet was baking, and life at the Equator struggled to survive.

Plants gobble up carbon dioxide, which warms the planet. So without them, Earth became like a runaway greenhouse, it started to get out of control.

The few life-forms that had survived the Permian extinction—such as hardier snails and clams—died in the deadly heat, leaving Earth a virtual “dead zone” for five million years. Learn more here.

50,000 year old human genome sequenced

November 6, 2012

In a stunning technical feat, an international team of scientists has sequenced the genome of an archaic Siberian girl 31 times over, using a new method that amplifies single strands of DNA. The sequencing is so complete that researchers have as sharp a picture of this ancient genome as they would of a living person’s, revealing, for example that the girl had brown eyes, hair, and skin.

That precision allows the team to compare the nuclear genome of this girl, who lived in Siberia’s Denisova Cave more than 50,000 years ago, directly to the genomes of living people, producing a “near-complete” catalog of the small number of genetic changes that make us different from the Denisovans, who were close relatives of Neandertals.

A tiny finger bone from Denisova Cave

Ironically, this high-resolution genome means that the Denisovans, who are represented in the fossil record by only one tiny finger bone and two teeth, are much better known genetically than any other ancient human—including Neandertals, of which there are hundreds of specimens. Learn more here.

100-Million-Year-Old Spider Attack Recorded in Amber

October 24, 2012

This one really was a fight for the ages. Researchers have discovered the only fossil known of a spider attack on prey caught in its web. The young male arachnid (top) was just about to pounce on a tiny parasitic wasp when the pair became smothered in tree resin in the Hukawng Valley of Myanmar 97 million to 110 million years ago. The result was a fossilized piece of amber that captured the event—complete with spider silk—in remarkable detail.

Learn more here or here.

Thanks to Birds we have no more Giant Bugs

July 17, 2012

Sure, they provide the soundtrack of spring and are often lovely to look at. But a new study may offer the best reason yet to appreciate birds: the general absence of gigantic insects from our daily lives.

Today insects are among the smallest creatures on Earth, but about 300 million years ago, huge bugs were fairly common. The dragonfly-like griffinfly, for example, had a wingspan of about 70 centimetres—a little bit smaller than a crow’s. Today’s widest-winged insects are butterfly and moth species that span about a foot (30 centimeters).

The prehistoric bugs’ incredible growth was fueled by an atmosphere that was more than 30 percent oxygen, compared with 21 percent today, experts say. The extra oxygen gave bugs more energy per breath, allowing them to power bigger bodies.

But things changed about 150 million years ago, during the Jurassic period, when the first birds appeared alongside dinosaurs. After birds took to the skies, winged insects stopped growing bigger—even as oxygen levels rose.

As to why the big bugs might have fallen to birds, the maneuverability of any sort of flying thing really scales with size. Small things are much more maneuverable than large things. In other words, large insects may have been easy targets. Another possibility is that birds may simply have eaten the big bugs’ lunch. The birds may have m0re successfully competed for food sources.

The largest insects today could perhaps be three times as large as they currently are, based on current oxygen levels – hip, hip, hooray for birds!!! Learn more here.

Spectacularly Preserved Fossil Suggests Most Dinosaurs Were Feathered

July 9, 2012

A newfound squirrel-tailed specimen is the most primitive meat-eating dinosaur with feathers, according to a new study. The late-Jurassic discovery, study authors say, challenges the image of dinosaurs as “overgrown lizards.”

Unearthed recently from a Bavarian limestone quarry, the “exquisitely preserved” 150-million-year-old fossil has been dubbed Sciurumimus albersdoerferi—”Scirius” being the scientific name for tree squirrels.

Sciurumimus was likely a young megalosaur, a group of large, two-legged meat-eating dinosaurs. The hatchling had a large skull, short hind limbs, and long, hairlike plumage on its midsection, back, and tail.

Previously, paleontologists have found feathers only on coelurosaurs—birdlike dinosaurs that evolved later than so-called megalosaurs such as Sciurumimus.

Because Sciurumimus is not closely related to coelurosaurs, the new fossil suggests feathered dinosaurs were the norm, not the exception. Learn more here or here.


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