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Showing posts with label dinosaurs. Show all posts
Showing posts with label dinosaurs. Show all posts

Friday, April 6, 2012

The Biggest "Bird" EVER (Was Pretty Much T. rex!)

Remember watching the movie Jurassic Park for the first time, and there’s that scene where the big scaly Tyrannosaurs rex busts through the fence and walks between the stalled Jeeps, growling and snarling and eating goats? It’s scary, intense, and pretty darn realistic – after all several top palaeontologists served as scientific advisors to the film, like Jack Horner, whose current theories are still well respected in the scientific community (/sarcasm). Yeah, turns out that, like most everything Hollywood puts out, Jurassic Park is just a movie, and real life is nothing like it.

To be fair, Jurassic Park was an awesome movie... mostly because of Sam Neill. Sam f'in Neill.

I’ve talked before about the Liaoning shale gardens in northern China, where scientists have been finding exquisite fossils of dinosaurs and birds with their feathers preserved in mind-blowing detail. Until now, these fossils have been of smaller animals, perhaps crow or raven-sized at the largest, but dinosaurs living there ran the size gamut, and some were much larger than their tiny maniraptoran relatives. Much, much larger.

The tiny maniraptoran Mei long, looking just as much bird as dinosaur.
By Ferahgo-the-Assassin via deviantart.

Enter Yutyrannus, a 30-ft-long tyrannosauroid dinosaur that looked decently enough like the Tyrannosaurus we all know and love – top-heavy, with a powerful head filled with sharp teeth, strong muscular legs, and tiny little arms. In all, three Yutyrannus fossils were discovered, and at least one was preserved very similar conditions to recently famous feathered dinosaurs like Microraptor and Anchiornis. All along its body, in long down-like plumes, the Chinese scientists found something never before seen on such an enormous dinosaur – feathers.

Fuzzy tyrannosaurs have been scientifically proven. Your argument is invalid.
By Gorgosardia via deviantart.

Ever since the primitive Dilong, we’ve known that tyrannosaur-like dinosaurs could possess feathers. However, there’s a biological theory that as an animal grows larger, it requires less integument to regulate its internal body heat, much like elephants are pretty much hairless today. So, everybody just kind of assumed that even though the tiny Dilong had feathers, Tyrannosaurus rex was huge and probably just scaly. Now we know that Dilong wasn’t a fluke in the tyrannosaur lineage, and it’s likely all tyrannosaurs were feathered to some extent.

You're gonna have to zoom in to see them, but Yutyrannus's filaments don't lie!
Photo via Sci Tech Update.

Yutyrannus, however, took “some extent” to its full extent. Its feathers were pretty primitive, and lacked the vanes and intricate barbs of bird feathers, so in life the it would have looked pretty furry. Much like northern China is pretty cold today, it may have been even colder in the Cretaceous, meaning Yutyrannus’ feathers were probably used to regulate its body temperature. This has implications for dinosaur fossils found in extreme latitudes like Antarctica and even Australia. Back in the day, the two continents were found quite close to the South Pole, and dinosaurs like Cryolophosaurus probably had similar integument to brave these frigid climes.

Once this reconstruction of Cryolophosaurus was merely speculation - but now it's looking more and more likely!
Photo by Kyoht via deviantart.

There’s another implication, of course. Dinosaurs like Dilong and Yutyrannus were fairly early offshoots of the coelurosaurian family tree, and not particularly closely related to maniraptoran dinosaurs and their progeny, birds. So it seems that feathers, or at least down-like integument, was a primitive feature for these animals. But how primitive? Could the early Dilophosaurus have possessed feathers? Or Coelophysis, one of the most basal therapods?

A slice of life from the Cretaceous? A maniraptoran Mononykid dinosaur feeding its chicks.
Photo by Deinowilly via deviantart.

Dinosaurs evolved along two main lines – ornithischians (plant-eating dinosaurs) and saurischians (meat-eating dinosaurs). All the feathered dinosaurs I’ve talked about today have been saurischians, but the very same shale gardens in China have unveiled several ornithischian dinosaurs that possess odd, hollow, quill-like structures – not feathers in the strictest sense, but similar integument. Some, like the ceratopsian Psittacosaurus, only grew them on the tail, and probably used them for display. But a much more primitive ornithischian, Tianyulong, grew these structures all over its body, and perhaps used them for heat regulation. In short, it was another furry dinosaur, albeit one from a completely different side of the family tree.

Man, dinosaurs have really changed from when I was a kid... for the better, in my opinion!
Photo via MSNBC.

These and other recent fossil finds confirm what paleontologists have known for some time now. Those dinosaurs we today know as birds are not as unique in the ways we once thought. Most dinosaurs grew some type of feathers, and other dinosaurs could fly, some perhaps even capable of powered flight. But truly avian dinosaurs are indeed unique in that everything about today’s birds is completely and totally specialized for one purpose – life on the wing. It’s important to realize that dinosaurs were not the lumbering, scaly beasts depicted in children’s books not a decade ago. Like birds, they were graceful, active, and most importantly, beautiful.

Thursday, September 15, 2011

Interlude: Dinosaurs and their Feathers

If there's one thing I like more than birds, it's dinosaurs. Big, lumbering, small, graceful, dinosaurs came in all shapes and sizes. The largest is somewhat debatable - Argentinosaurus is the biggest we have good data on (it was somewhere in the range of 100+ feet, and quite massive), but if the bones of Amphicoelias hadn't been lost, we'd be looking at a 200-foot behemoth! The smallest dinosaur, however, we can know for sure. Discovered almost 160 years ago, it's the little 2-inch long Mellisuga helenae - the Bee Hummingbird.

You're looking at one of the most ferocious predators of all time!
Photo from TripAdvisor.

That's right, birds are dinosaurs, albeit highly evolved ones. They're a direct descendant of the dinosaurs in Maniraptoriformes, better known to the layman as the raptors. Most people would consider Archaeopteryx to be the oldest known bird, but in fact it's just another dinosaur, an advanced Deinonychosaurid closely related to the Troodontidae and Dromaeosauridae (Xu et al., 2011). Even the famous Velociraptor has been shown to have quill knobs on its arms, a tell-tale sign of flight feathers (or something akin to that). To recap - Birds are dinosaurs. Archaeopteryx is a dinosaur. But Archaeopteryx is not a bird.

Not visible in this picture - the hyperextensible second toe, better known
as the "raptor claw", which Archaeopteryx is now know to possess.
Photo from Wikipedia.

To have feathers does not necessarily make you a bird. Until the 1990s, Archaeopteryx was the only known dinosaur fossil with preserved feathers (of course, remember everybody thought that fact made it a bird). Since then, feathered dinosaur fossils have been flooding in from China, most showing primitive filamentous feathers, although more than a couple show vaned feathers that could make them capable of flight. However, these fossils are just the impressions of feathers, an imprint of an animal that died in favorable sediment. You can't walk down the street and pick up a dinosaur feather like you can a discarded bird feather. Or, you couldn't. That is, until today.

Say whaaaaat?!
Photo from The Atlantic via Science.

In the journal Science, researchers reported specimens of amber from Alberta that date to around 80-million years ago (you may note that non-avian dinosaurs still had another 15-million years to go on the Earth). Some of the amber showed what are clearly vaned bird feathers, but others show the trademark filamentous feathers of dinosaurs. Just how the feathers became trapped in the amber, I'm not sure, but the fact remains - we as a world community are now in the possession of real, honest-to-God dinosaur feathers. Now if we can just find an eccentric old Scotsman to pony up the cash and clone these bad boys.