Supersaurus may still be a valid taxon, but Ultasaurus is just a big Brachiosaurus. Supersaurus is kind of up in the air. It's difficult to differentiate from other Morrison sauropods.
DREADNOUGHTUS (awesome name) is questionably the heaviest dinosaur on record. The SV-POW guys have a great series of posts about the math behind Dreadnoughtus and whether it really was the biggest on record (bottom line: hard to say):
http://svpow.com/category/titanosaur/dreadnoughtus/http://svpow.com/2014/09/05/brief-thoughts-on-dreadnoughtus/Also, the paper itself is open-access. You can read it yourself!
http://www.nature.com/srep/2014/140904/srep06196/full/srep06196.htmlNow, certainly there are already a wealth of ridiculously enormous titanosaurid sauropods: Argentinosaurus, Puertasaurus, and Alamosaurus (from Texas!) also come to mind. These were huge animals no matter how you slice it. The scary part is that Dreadnoughtus was apparently STILL GROWING, but how much bigger it would've gotten is a complete unknown.
There's something more exciting to talk about than Dreadnoughtus anyway: SPINOSAURUS AEGYPTICUS.
I BE IN YO' RIVERS, EATIN' YO' FISHES!
There's been an ENORMOUS media push by National Geographic covering this "new" discovery. I say "new" in quotes because it's actually over a decade old. So we've all seen Jurassic Park III, right? And there's that new Big Bad, Spinosaurus, that totally kills T.rex by breaking its neck which is totally something dinosaurs did by the way. All the time. Very bloodless killing in the Mesozoic. Spinosaurus is a real animal--discovered by Ernst von Stromer in 1915 in Egypt. Unfortunately, he really only found a bunch of vertebrae (hence the sailback) and a dentary.
Those remains were put up in a German museum and I think you can see where this is going. World War II comes along, the Allies bomb the f*ck out of Germany, and those fossils (and a ton of others) are destroyed utterly. Thankfully, Stromer made excellent drawings of the bones and took wonderful photographs. He described them in loving detail--in German--but he essentially "preserved" Spinosaurus in the eyes of science. Unfortunately, only bits and pieces have come out of Egypt since, but more material from Morocco.
Among the best new fossils in recent years has been this snout fossil, shown here held by Some Guy:
That's a BIG ANIMAL.
Other critters were discovered since 1915 like Baryonyx in England and Suchomimus in Niger--and to a lesser extent, Irritator in Brazil--that helped to flesh out what "spinosauroids" looked like. Basically, they looked like normal theropods, but with crocodile skulls and HUGE thumb claws. Lots of studies now have shown that they were big fans of sushi, and spent a lot of time in and around the water. But it was always assumed that they were basically dinosaurian bears or herons, standing in the water and grabbing fish that passed under them.
The "Spinosaurus" in Jurassic Park III is basically a Hollywood-ized Suchomimus with a ridiculous sailback. It was NOT a super-predator, it would NOT have been able to hold off a Tyrannosaurus (or even its neighbor, Carcharodontosaurus) and its jaws would have snapped with any significant amount of torque applied. Less crocodile and more gharial, honestly.
But it was HUGE. We're talking T.rex sized or probably bigger.
So what's the new news?
Well, a group of paleontologists reported on what's essentially a collection of material that they examined or discovered over the years. It was found across two countries, represents numerous individuals and probably different age classes, but ALL TOGETHER gives a pretty good example of what Spinosaurus actually looked like. And if they're right, it looked really strange. The sail has two high points, the tail is abnormally long, but it's the hind limbs that are ridonk: they are really short by theropod standards. The authors suggest that it wasn't CAPABLE of bipedal locomotion on land. What's the basically say in the paper is that Spinosaurus is a more-or-less fully aquatic dinosaur, like early four-limbed whales were fully-aquatic mammals.
This is nuts. And there are problems with their reasoning.
Scott Hartman has two excellent posts about the proposed hindlimb proportions:
http://www.skeletaldrawing.com/home/theres-something-fishy-about-spinosaurus9112014http://www.skeletaldrawing.com/home/there-may-be-more-fishiness-in-spinosaurus9132014And Jaime Headden has a similarly great post about the cobbled-together skeletal:
http://qilong.wordpress.com/2014/09/12/the-outlaw-spino-saurus/Finally, if your browser supports translation, Andrea Cau has a series of posts about various aspects of this new Spinosaurus discovery:
http://theropoda.blogspot.com/Finally, the always-reliable Brian Switek (buy his books!) offers a great summary here:
http://phenomena.nationalgeographic.com/2014/09/11/the-new-spinosaurus/National Geographic, for its part, has funded a life-size, flesh model (that's ironically standing on two legs) and a "swimming" skeletal model. There's clearly a lot of money here, but I think it's based on some questionable conclusions. This is how science works, of course, and disagreement will lead to more work which will lead to clarification later on. It's exciting for ME to see all this discussion happening in real-time following the actual paper's publication. BTW, the paper is NOT open-access, but the supplementary materials are:
http://www.sciencemag.org/content/early/2014/09/10/science.1258750/suppl/DC1SCIENCE!