Dinosaur-killing Asteroid Confirmed

Meteor in the sky

Dinosaurs may have seen a glowing object flying at them like this 65 million years ago (photo courtesy of Navicore)

In the 1978 a giant crater was discovered on the Yucatan peninsula next to Chicxulub, Mexico.  35 years later we have real evidence to show that the impact coincided with the extinction of the dinosaurs.

Data shows that the impact matches to within 32,000 years of the dinosaurs extinction.  This is contrasted with previous studies that estimated the demise 300,000 years earlier—which is why some had maintained that other causes could have wiped out the dinosaurs.

Thanks to some clever radiometric dating of debris near the crater they are convinced that the 100+ mile crater caused an extremely long winter that killed the dinosaurs.  For a visualization of the event see the video below.

References

http://www.sciencemag.org/content/339/6120/684

http://www.theverge.com/2013/2/10/3973338/dinosaurs-extinction-caused-by-asteroid-study-shows

What Color Were Dinosaurs?

Colorful Parrots

Birds come in many vibrant colors, but could their ancestors have been so bright?

Scientists now know what colors some dinosaurs were–thanks to melanosomes that contain pigments found in some dinosaur fossils. Turns out that Sinosauropteryx, a small carnivore, had a tail with red and white stripes, and Anchiornis Huxleyi had grey and black feathers, white stripes on its wings and legs, and a red crest on its head. Continue reading

The Long-Necked Dinosaurs

How huge hollow bones helped them grow

A seismosaurus reconstruction

A seismosaurus neck reconstructed with hollow bones

Dinosaurs, or more specifically sauropods, had the longest necks of any other creature that has ever lived on Earth. A sauropod could have a neck up to 50 feet long, six times longer than a giraffe’s neck, according to Live Science.

But how did their necks get so long?

Apparently, it had to do with their hollow bones.

In a recent study, led by paleontologist Michael Taylor and published in PeerJ, researchers found that 60 percent of sauropod necks consisted of air, and some necks were just as light as the bones of birds. It also helped that sauropods had large torsos, stood on four legs, and had up to 19 neck vertebrae. Additionally, sauropods had heads so small they were basically just mouths—and they didn’t even have cheeks! Because of this, they didn’t chew their food; they just swallowed it.

One good thing about being built like a bird is it allowed sauropods to continuously “draw fresh air through their lungs,” according to Live Science. This made it much easier to breath than if they had to breathe like mammals, meaning they would have to breathe out before breathing in again.

There are a few reasons why sauropods evolved to have long necks. Maybe they needed a long neck to reach leaves on tall trees, or maybe they swept their neck from side to side to graze on grass. Another theory is that long necks attracted potential mates. In Live Science, Taylor said he and his colleagues suspected that Apatosaurus males combated each other with their necks, probably to fight over females. Apatosaurus apparently had a bifurcated neck that made them extra wide and deep.

Dinosaurs the size of chickens

What’s for dinner?  Yulong.

chicken picture

bwak bwak! I’m as big as dinosaur!

 

Yes, we’re still discovering new types of dinosaurs. A new one, called Yulong mini, apparently had offspring the size of chickens—the smallest dinosaurs ever found, according to a study in Naturwissenschaften, as cited on Discovery News.

Yulong was discovered in the Henan Province in central China, by archaeologist Junchang Lü and his colleagues. They are classified as oviraptorids, also known as “egg thieves.” However, in the 1990s, scientists came to the conclusion that these dinosaurs used other dinosaurs’ nests for brooding, instead of stealing eggs.

One interesting find with the study of Yulong is the fact that oviraptors may have been herbivores, and not carnivores, as previously thought. Additionally, Yulong babies most likely grew up without parents caring for them.

Yulong apparently looked like a chicken with a tail, though it could grow to 26 feet long. But Yulong is not an ancestor of birds, since all non-avian dinosaurs went extinct about 65 millions years ago. However, Yulong not only looked like a chicken, but it also was popular prey, and T. rex and other carnivorous dinosaurs enjoyed eating it. Too bad we’ll never know if it tasted like chicken too.

Scarred-fossilized dinosaur skin unearthed

 How a duckbill escaped a huge predator

scales on a claw

Scales on the claw of a modern animal which researches say would heal similar to a dinosaur if injured

Fossilized skin was recently discovered in the Hell Creek region of Montana.  What makes this skin unique—apart from being over 65 million years old—is that it shows how dinosaurs healed.  Remarkably, they also found a matching skull to show the extent of the attack that the Hadrosaur survived.

Looking at the pattern of scales they noticed an area with scales which didn’t match the overall pattern.  Comparing the suspected scar to modern tissue with similar wounds they confirmed that the Hadrosaur was attacked by a large predator.

The find was reported by Cretaceous Research (click here for pictures of the skin and skull damage).  They point out that “Healing skin injuries appear to be rare in the fossil record for good reason – prey rarely escapes once the attacker latches onto it.”  Possibly the most interesting piece of evidence is that T. Rex was known to roam the area in large numbers possibly casting doubt on the recent opinion that T. Rex was a scavenger and not a predator.

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