New species of dinosaur discovered - could be one of the biggest that ever lived

[sauroid]

newly discovered Russian sauropod tentatively named "Sibirosaurus" could be the "biggest" dinosaur ever discovered

http://www.mirror.co.uk/news/world-news/new-species-dinosaur-discovered---5416999

[DinoLord]

Interesting find; I wonder how much material they recovered. Unfortunately these big titanosaurs always seem to be rather fragmentary.

[Derek.McManus]

Interesting find, these dinosaurs just seem to get larger and larger!

[Yutyrannus]

Isn't there also still an unnamed giant titanosaur from Argentina?

[Pachyrhinosaurus]

Isn't there also still an unnamed giant titanosaur from Argentina?

IIRC that was dreadnoughtus. Its strange to hear about a dinosaur of this size not from Argentina.

[Balaur]

No, that wasn't Dreadnoughtus. The unnamed titanosaur is from the Cenomanian, Dreadnoughtus is from Campanian.

[Pachyrhinosaurus]

No, that wasn't Dreadnoughtus. The unnamed titanosaur is from the Cenomanian, Dreadnoughtus is from Campanian.

I thought they were one and the same. Regardless, that only goes to show that there are a lot of giant titanosaurs being discovered at this time.

[Balaur]

Which leads back to the question; why did they grow to such huge sizes? I've always thought it was defense against predators, but don't titanosaurs have some sort if body armour? If this new "Sibirosaurus" is as big as it is currently thought to be, then maybe there being something special about Argentina to have them be so big isn't true, and... I don't know where I'm going with this. 

[laticauda]

They are never as big as they say they are.  Insert "thats what she said" joke.   

[Dinoguy2]

Which leads back to the question; why did they grow to such huge sizes? I've always thought it was defense against predators, but don't titanosaurs have some sort if body armour? If this new "Sibirosaurus" is as big as it is currently thought to be, then maybe there being something special about Argentina to have them be so big isn't true, and... I don't know where I'm going with this. 

Having armor can usually deter a predator, especially if you're a juvenile. Usually. (The first ever T. rex specimen was found with ankylosaur scutes in its stomach contents...). Gigantic size means predators won't even look at you. They're basically predator proof. No predator in its right mind would even try to attack something that big, too big a risk of injury. They'll go for the smaller guy down the way (even though he has armor).

[Tyto_Theropod]

Which leads back to the question; why did they grow to such huge sizes? I've always thought it was defense against predators, but don't titanosaurs have some sort if body armour? If this new "Sibirosaurus" is as big as it is currently thought to be, then maybe there being something special about Argentina to have them be so big isn't true, and... I don't know where I'm going with this. 

Having armor can usually deter a predator, especially if you're a juvenile. Usually. (The first ever T. rex specimen was found with ankylosaur scutes in its stomach contents...). Gigantic size means predators won't even look at you. They're basically predator proof. No predator in its right mind would even try to attack something that big, too big a risk of injury. They'll go for the smaller guy down the way (even though he has armor).

To be fair, the Tyrannosaurus could have been scavenging an Ankylosaur carcass. Now I certainly don't believe that T. rex was 100% scavenger, but all predators are opportunists. If they find a dead animal, chances are they'll feed on that rather than waste energy on a hunt that might not even be successful. Which isn't to belittle your argument, I completely agree. Look at elephants. Look at the bigger whales. You don't see lions or tigers or sharks going after them, simply because they're so huge. The only animals I know that can take down a baleen whale is a killer whale, and they're pretty large themselves, plus they hunt in coordinated groups. I've still never heard of them trying to take down something like a blue, humpback or bowhead, though.

In other thoughts, I wouldn't get too excited about it being THE BIGGEST - this is the Mirror we're talking about... XD Also:

"This adult dinosaur lived in the Late Cretaceous period, so about 100 million years ago."

FAIL.

Titanosaurs were a diverse group of sauropod dinosaurs that included the likes of the Saltasaurus, Diplodocus and Brachiosaurus.

The Mirror has just rewritten Sauropod phylogeny!

[Blade-of-the-Moon]

Predatory behavior toward dinosaurs so large could involve several methods. Predation on mainly old/sick/deceased  and young or maybe they treated a herd of these animals like a moving buffet. Grab a mouthful and run..

[Takama]

I always imagined the Moving Buffet idea was the better possibility.

A predator would run up to a Sauropod, and rip a bit of flesh off of it, repeat until full, or the sauropod falls due to blood loss

[Tyto_Theropod]

Or they were simply so big that they survived the wound. Also, we mustn't forget an often overlooked source of food for predators: babies. Given how small known Sauropod eggs are, the babies can't have started big.

[stargatedalek]

Orca will attack adult sperm and grey whales, so I wouldn't think a humpback or bowhead would be too large for them. I've heard before of orca's attacking blue whales but the only reference I could find was this link (*somewhat graphic* http://www.worldfishingnetwork.com/california-fishing-guide/video/rare-footage-of-killer-whales-attacking-a-blue-whale ) which seems to show a pod of orca attacking a sub adult blue whale, but I'm not sure how valid Fishing Network is at ID'ing whales.

Perhaps the moving buffet idea of sauropod predation (on healthy adults) is a better analogue to oxpeckers.

[Tyto_Theropod]

Orca will attack adult sperm and grey whales, so I wouldn't think a humpback or bowhead would be too large for them. I've heard before of orca's attacking blue whales but the only reference I could find was this link (*somewhat graphic* http://www.worldfishingnetwork.com/california-fishing-guide/video/rare-footage-of-killer-whales-attacking-a-blue-whale ) which seems to show a pod of orca attacking a sub adult blue whale, but I'm not sure how valid Fishing Network is at ID'ing whales.

Perhaps the moving buffet idea of sauropod predation (on healthy adults) is a better analogue to oxpeckers.

Interesting. I knew about their attacking sperm and grey whales, which is why I said "the bigger" whales. I apologise if I wasn't clear. Marine biology isn't my strong card. I can, however, see that the whale they're attacking is certainly a big one, although I'm not sure if it's a blue whale as it's hard to make out much of its body under the water. A brief search on Google also turned up some mentions of killer whales taking down blue whales 'on rare occasions', but of course we're talking marine species here. Sometimes they'll be in the middle of the open ocean, making them very hard to observe, so for all we know these attacks could be happening more often than we think. So I stand corrected on this.

However, I'm also going to point out that killer whales are one of the most intelligent known species on the planet, ever, as evidenced by their complex social structure, which allows them to hunt using coordinated teamwork. Although it's not impossible that dinosaurs such as Mapusaurus could have used this method (as has been interpreted from the discovery of a Mapusaurus bone bed containing fossils of about seven individuals of different ages), as with all bonebed fossils the theory has to be taken with a pinch of salt. The truth is we simply don't know if any dinosaurs hunted in groups, let alone coordinated ones. If they did, though, large predators like Mapusaurus would definitely have been able to take down a giant Sauropod.