Carnivorous dinosaurs other than the famous t-rex and spinosaurus..

[Verdugo]

(09-28-2019, 01:30 AM)DinoFan83 Wrote: 2: True. However, confirmed sizes are close enough for a fair debate. And, as I said earlier in this thread, large theropods in general had decent weight ranges so I see absolutely no reason why that would not apply to big carnosaurs.

I already said above that i also think it's unlikely that the Carcharodontosaurid specimens we have are representative of their species. However, i have also pointed out that when dealing with extinct taxons, you need something more concrete than just some vague assumptions like 'how large this species could get'. One could also argue that some T-rex specimens could go pass 10 tonnes and it's just as legitimate as your argument that some Carcharodontosaurid specimens could go pass 8 tonnes. In fact, if not even more legitimate. For example, Hutchinson (2011) estimated the mass of Sue at 9.5 tonnes based on volumetric method (laser scanning the skeleton cast). And Sue is a complete skeleton. On the other hand, mass estimates of 8+ tonnes for Carcharodontosaurids are usually based on bad methodologies that do not have much scientific soundness to it such as isometric scaling of very fragmentary remains. In fact, we have an improve method of isometric scaling, it's called regression (because regressions allow you to incorporate more specimens and data). And even so, regressions are rather a hit or miss sometimes...

The only sort-of legitimate 8+ tonnes estimates for Carcharodontosaurid comes from Hartman's Giganotosaurus MUCPv 95 based on assuming that it's 6.5% larger than the holotype. However, Hartman himself even stressed that 6.5% assumption is about as liberal as he will go

Scott Hartman Wrote:7)  I must reiterate, the lower jaw fragment of MUCPv-95 does not come from an animal that is 8% larger than the type. In fact it honestly could be from an identically-sized animal that just has a more robust dentary, so scaling it up 6.5% (in linear dimensions) should if anything be seen as the upper bounds.

To summary, the 8+ tonnes estimates are quite concrete. On the other hand, the 8+ tonnes estimates for Carcharodontosaurids are meh, for lack of better words. Maybe one day we will discover larger specimens but let just wait for that 'one day' rather than making baseless assumptions...

(09-28-2019, 01:30 AM)DinoFan83 Wrote: Besides, my only point was why I felt carnosaurs were overall superior to tyrannosaurs at parity. And parity is pretty close from what we do know

I figure parity debate would have been more interesting but that's not my point here. You can make a hypothetical assumption for a parity match-up between whatever animals as you like, i don't really care for that but you cannot state it as factual that Carcharodonosaurids weighs as much as those big T-rex specimens simply because, as i said above, i have yet to see anything concrete about 8+ tonnes estimates for Carcharodontosaurids. It's a possibility that they could weigh that much, yes, but where are the evidences?

(09-28-2019, 01:30 AM)DinoFan83 Wrote: 1: And that may give Giganotosaurus a bit more of a chance because a larger skull will give more reach for a bite and allow a bigger area of a bite. (but not THAT much more, just a small edge)
3: A longer skull grants more reach, and therefore more of a chance to land that first bite, as well as a larger area bitten and damaged. And a wider gape only adds to the 2nd advantage.
4: Wouldn't these only hold relevance if the disparity was so significant as in, say elephant and mouse, or bat and ichthyosaur? I'm not discounting them but wouldn't they have to have more disparity to have a large impact?

So you think that 15 cm more reach on 12+ m animals is a 'decisive' reach advantage but something like 'twice as much agility' (Snively 2019) or significantly better field of visions negligible? For example, if it takes a Giga 2 secs to make a 90 degree turn, it will only take a T-rex 1 secs to do that, that's essentially what it means to have 'twice as much agility'.

Regarding visions, T-rex has better binocular vision than that of Hawks and in Stevens 2006's words, allows for 'judging the timing and direction of a terminal lunge' vs the narrower binocular vision of Allosauroid that would have 'detected preys on the basis of motions'. In fact, refer to Stevens 2006 Fig 8, Carcharodontosaurus actually requires to tilt its head downward about ~20 degree from the horizontal line just to achieve some narrow binocular visions. If it does not tilt its head downward to that point, it would have no overlapping visions at all and would literally have a blind spot right in front of its face. Now, obviously, not all Carcharodontosaurids are like Carcharodontosaurus but that it something to keep in mind here.

Really can't see how having 15 cm more reach would be more decisive than these factors but i figure it probably depends on perspectives.

(09-28-2019, 01:30 AM)DinoFan83 Wrote: I have absolutely no idea where the myth of crushing bite>slicing bite stemmed from

Didn't say anything about that. However, it's needed to point out that the whole crushing vs slicing bite things are not two mutually exclusive concepts and that animals can only pick one. For most macrophagous animals, it's actually somewhat in between. For instance, Tiger sharks' teeth allow it to crush and slice. Or Hyenas who are usually considered to be bone crushers can slice meat just as well (Hyenas have enlarged but blunt premolars for crushing bones and sharp carnassials/molars for slicing meat). T-rex's teeth have serrations that would allow it to slice meat to a certain extent (though obviously not as good as that of Carnosauria)

Personally i would prefer something with robust teeth and skull that could facilitate 'jaw grappling' (holding, pulling, shaking, controlling). Personally, i can imagine that T-rex could survive if a Carcharodontosaurid bites down on its head, however, i can't imagine it the other way around. But again, different perspectives i suppose, i would not argue with you on this. Reply