Giganotosaurus and Tyrannosaurus: which is the biggest?

You've made good points. Although I see your line of thinking, I wouldn't think the last comparition very reliable. The biggest specimens of T.rex aren't giants compared to the others, but they're simply bigger. A fitter comparison would be between normal persons: some can be skinny, fat, taller, shorter... of course not all of the individuals are the same size. And I get it. A reasonable medium estimate for Tyrannosaurus would be 6.5-7 tons, based on the many, many specimens we have discovered. But as you stated, it's a totally different thing when it comes to Giganotosaurus. The skeletons we have are not complete enough to give us a better estimation like in Tyrannosaurus. I think it's just not the best thing to compare these two, exactly because of the fragmentary state of the latter's founds.

Robert Wadlow is a bad example as his height was due to a bone disease. You should more likely use Angus McCaskill as example who was a normal, healthy, giant Homo sapiens.

For now, comparing T. rex and Giga is a matter of specimens to specimens but some points :

- the dentary from the second Giga is a small fragment which suggests, or does not suggest, a larger individual than the holotype. Depending of the intraspecific proportions.

- if we take into account this small dentary from Giganotosaurus, we can take into accounts the fragmentary T. rex remains which suggests individuals as large or maybe larger than Sue.

- Sue might be the biggest T. rex, but several quite complete specimens are almost as big. The holotype Carnegie specimen is estimated almost as large as Sue. Campione et al. 2014 considers Scotty to be slightly larger (heavier) than Sue.

So, using parcimony, I think the edge is still for Tyrannosaurus, for now.

My point was that max. size isn't the only one wich must be take in account.

Larger than Sue thing isn't what I call a likely and verified thing. MOR008 isn't even larger, UMCP 137538, if scaled from Sue, is 47 feet long, but the answer is - is that a T.rex? Even if it was, when scaled from Stan, it's around as big as Sue. It looks like that C-rex's size was just guessed by Horner, and UCMP 118742 is already an adult, according to Theropod Database.

We do not have nearly enough giga specimens to assume which is bigger. And as others have previously stated, Waldo is not. Good example since he is an outlier compared to the rest of the world. While large t.rex specimens are only a bit larger.

I would say they were around the same size too, but I think Giganotosaurus was slightly bigger.

Gigadino,

Yes but if you exclude the fragmentary possibly Sue-sized or larger T. rex individuals, my point is that you can exclude too the dentary from the second Gigantosaurus which is a small fragment suggesting various possible estimates.

We can found new larger individuals but we can found new larger T. rex individuals too, Tom Holtz explains it well here :

http://news.nationalgeographic.com/news/2013/10/131016-tyrannosaurus-rex-smithsonian-wankel-fossil-day/

But really if we take all the optimistic possibilities as of now, Sue is slightly larger than the largest Giganotosaurus and there are several compkete T. rex individuals as heavy as the second Giganotosaurus and several T. rex specimens as large as Sue and possibly larger.

Unless we found tomorrow a 14 m Giga, T. rex seems slightly the bigger guy.

Lord of the Spinosaurs,

http://www.skeletaldrawing.com/home/mass-estimates-north-vs-south-redux772013

Now I say the two super predators were the sane size. Though the giga specimens are not complete at all so we can't compare it to a mostly complete t.rex.

Fragmentary, Sue-sized or bigger T.rex are definitely more doubtful than MUPCv-95, for the motivations I stated above. MUPCv-95 may simply had a proportionally bigger jaw, but what about a proportionally smaller jaw? Assuming that its jaw was proportionally bigger is as likely as assuming that it was proportionally smaller. Given that it's fragmentary, a good rough figure would be 12-13 m.

I have no problem with MUPCv-95 at 13 m or slightly more.

Parcimony would exclude however than this specimen was smaller-jawed.

Scotty is considered bigger than Sue by Campione et al. 2014.

Carnegie is almost as big as Sue and slightly larger than the holotype Giga.

I dont think that it is fair to ignore the several not (yet) published T. rex individuals. The without a doubt exist and exhibit for some large features.

The uncertainties in them for size estimates are just the same than for MUCPv-95. Even including the huge toebone (I dont see why it would be something else than a very large or big-footed T. rex).

If you think that we should consider even undescribed animals, well, let's take in account Das Monster Von Minden, wich is considered to be 15 m long. Most the information about undescribed animals come from media, wich aren't reliable.

I dont use the mediatic estimates.

All the figures for these unpublished or not totally published specimens (Celeste is cited in Peter Larson's book) come from the paleontologists words and from the actual measurements of the material.

The giant toebone is real and a published measurement is known, there's no mediatic speculation in that.

Also, I refer to other quite complete T. rex specimens other than Sue, which are larger than Giga's holotype and for some as large or larger than Sue (Scotty, perhaps MOR 008) so larger than MUCPv-95 (weight wise of course).

MOR008 is smaller than Sue.

The famous UCMP is even more fragmentary than MUPCv-95. By a comparison, Amphicoelias is know from better remains. When you scale UCMP from Stan, it would end up not bigger than Sue.

Huu Amphicoelias is a long lost bone known by an old incomplete drawing.

UCMP  is an actual bone in collection researchers have access too.

If UCMP at worst suggested a Sue-sized beast it means :

-bigger than MUCPv-95

-that Sue does not represent an exceptionnal individual (Scotty is considered bigger by Campione 2014 and Carnegie is almost as large).

For MOR008 it depends if you consider the size of the skull accurate but even at a lower 1.4 m, it suggests something bigger than the Giga holotype.

Sue-sized isn't the worst. It may have also been smaller than Sue. I see Sue as a very large specimen. We first discovered T.rex over 100 years ago, and the largest we found in a such quantity of years - Sue - must be considered very large. 

MOR008 is smaller than Sue, its skull was actually 1.39 m long. 

However, you missed my point. Only one or two T.rex exceeded Giganotosaurus size, while the other are just as big or smaller. It's likely that both the taxon reached a similar size.

Smaller than Sue with a single toebone so much larger ? I know that we hve to be cautious while using small body parts as basis, but smaller than Sue with a such massive bone is just as extreme as the isometric estimates you see everywhere on the internet.

The first specimen is almost as large as Sue and is larger than Giganotosaurus holotype.

MUCPv-95 size estimate is also subject to the same problematics than the one you suggest for the fragmentary large T. rex individuals and 13 m or so is not a necessary figure either. it could be also similar in size to Giga's holotype.

So all in all, both a quite similar but Tyrannosaurus, yes due to a sampling bias, has sligth edge.

Sue does not represent an exceptionnal specimen, Scotty is very large too and Holtz said that larger T. rex may very well have existed. That's just a large T. rex as far as we can tell.

The two were certainly comparable. On average, I'd say they reached comparable adult weights(Giga may have been slightly longer on average). Both probably averaged around 12-13 meters long and 6-8 tons with some giants exceeding that size. I'd say T.rex was slightly heavier, but Giga was slightly longer.

I agree with Carnosaur. It's not that it's impossible, but a more complete skeleton would certainly be nice. Only one specimen in my opinion has a good chance of being bigger than Sue and that's Celeste(even that one has some mystery around it).