Similicaudipteryx

It's already a well-known fact that China is the proverbial 90's mall for palenotiologists: everyone wants to be there since all the cool stuff is there. One thing that proves this is the discovery of Similicaudipteryx, annoucned this week in the journal Nature.

The fossils show feathers and how they changed as Similicaudipteryx aged. A juvenile and an older specimen were both found in western Liaoning, in China. Both fossils are approximatly 125 million years old.
Modern birds have fluffy down that is primarily to keep them warm, and once they molt, they grow what is essentially adult feathers. Similicaudipteryx, on the other hand, the juveniles have a "middle stage" in which their feathers are somewhat quill-like, more like ribbons than true feathers, while adults have more modern feathers. The younger individual also has longer feathers on the tail, while the elder had longer feathers on the wings.
The reason for this type of "feather evolution" isn't known why, but the different feather lengths for the different ages may be due to different needs: younger individuals would have a higher need to escape, while older individuals are more concerned about hunting and mating.

http://cosmiclog.msnbc.msn.com/archive/2010/04/28/2288537.aspx

Mastodons

The American mastodon was the last living member of the mastodon family, and lived around the Great Lakes, among many other places. The range was from Alaska to Honduras. The name came from it’s distinguishing feature, it’s teeth. Unlike the wooly mammoth, the mastodon’s teeth have nipple-like projections on the molars in order to suit it’s diet of leaves.

Paleontology Prime

Check out the album for pictures of a mastodon and on theories of their extinction.

The mastodons lived from 3.7 million years ago to 10,000 B.C., and there’s debate as to why they went extinct. One theory is that humans caused the extinction through hunting. Before man came to the continent, the only thing that could threaten adult-size mastodons would be American cave lions. The natural balance of predator and prey kept the numbers of both species in equilibrium. With humans present, suddenly more “predators” were killing mastodons and the balance was upset, even if only a few animals were killed each year.
Another theory was climate change. During the final few thousand years of the mastodon, the glacial ice sheet in North America was retreating. With the ice mass gone, weather changed. Large glaciers pull moisture out of the air and change natural weather patterns—the ice could be over a mile tall. With different temperatures and moistures, different plants bloomed. In order to still have the food supply they were adapted to, they had to move north along with the glacier. Eventually, there wasn’t enough food to keep their populations afloat, and they died out.
A third theory is that the lakes themselves locked them in the land that would become America, and that they died out when the food supply left. The Great Lakes formed when the retreating ice sheets pulled against the ground, and left giant gouges in the Earth. When they filled in, they became the lakes, and a very large and effective natural barrier. Very few mastodon fossils have been found north of the lakes, which gives credence to this theory.
What most likely happened is that all three of these theories described what happened. Ice sheets did retreat, whether did change, and humans did appear, and a mix of almost likely took them out.

Dino Fight

The Velciraptor, famous for wanting to kill small children in Jurassic Park, is known to be a fearsome predator. Recent fossil evidence, though, also suggests that sometimes they weren’t lucky enough to catch a break, and that they had to resort to scavenging.

Paleontologists dug up a Protoceratops fossil and two teeth from a carnivore in Mongolia, the home to the Velciraptor—not Montana as Jurassic Park says. Protoceratops is in the same family as the more familiar Triceratops, and is much smaller and lacks the trademark horns, but has a similar beak and neck frill.

The found teeth were matched to a Velociraptor, or a fellow raptor of similar size. The Protoceratops had scratches on the jaw and skull from the found teeth, which suggest scavenging. "This pattern is also seen in living carnivores — when faced with a large body, they start on the belly and hindlegs and the head is nearly always the last to go. Here the skull and jaws are the bones with the marks on and thus most likely to be the bits left over, not those first taken on,” said David Hone, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology of China in Beijing.

The picture with this article is of a famous fossil from another Protoceratops v Velociraptor meeting. Nicknamed “fighting dinosaurs,” the fossil depicts the two beasts fighting. Discovery Channel had a special on their series “Dinosaur Planet” in which the fight was recreated, and the fossil was recreated by two CGI dinosaurs fighting in a desert, and a collapse of a dune buried them both, thus creating a situation in which the fossil can be formed in such a way.

http://www.foxnews.com/scitech/2010/04/19/velociraptor-scavenging-larger-dinosaur/