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(09-26-2019, 08:41 PM)DinoFan83 Wrote: -Even with a 12.5% mass disadvantage, Giganotosaurus still has a bigger skull
1: Which means that, assuming weight parity, the skull of Giganotosaurus is 9.6% longer (not bigger) than that of T-rex. Assuming Giga weighs as much as Sue, it will have a skull length ~ 167 cm. So at weight parity, the skull of Giganotosaurus is ~15 cm longer than that of Rex.
2: However, i'm not sure what the point of assuming weight parity. There is no Carcharodontosaurid specimens that can be reasonably (emphasis added, so no, isometric scaling of fragmentary specimens will not be accepted) estimated to weigh as much as the big Rex specimens like Sue or Scotty. It's like saying that male Jaguar would beat male Lion assuming weight parity, which is pointless since male Lion is larger in real life. Yes, the specimens we have of Carcharodontosaurid are in no way representatives of their species so may be there are larger specimens out there, who knows. But in palaeontology, vague assumptions would lead you to no where. If you have no specimens, than no estimates, it's really that simple. In absolute term, Giganotosaurus's skull is not longer than that of T-rex.
3: Also, i'm not sure how having slightly longer skull would dramatically improve the chance of an animal to land a decisive bite. Having longer skull would surely help increase the gape, even assuming similar gape angle.
4: Some factors in favour of T-rex in landing a decisive bite such as binocular vision or agility that you might want to consider: Stevens (2006) regarding Tyrannosaurid's binocular vision:
Quote:The binocular capabilities provided by a BFoV 55º wide and
broadly separated, large eyes (with acuities perhaps better than
human) would allow not only observation of distant prey, but
also accurate perception of the three-dimensional arrangement
of potential obstacles to avoid during pursuit predation (Farlow
et al., 1995). For ambush predation, these binocular and spatial
acuities would have been more than adequate for judging the
timing and direction of a terminal lunge. For obligate scavenging,
these visual acuities would have been superfluous
In contrast to Allosauroid who has a narrower field of binocular vision:
Quote:The maximum binocular overlap for the allosauroid design
was slightly less than that of extant crocodilians and close to that
predicted for the basal oreinirostral cranial design. The descending
ramus of the lacrimals acted as medially placed blinders in
restricting contralateral vision, while dorsally, binocular vision
was further limited by lacrimal horns and other rugose features
along the snout. These allosauroids, by analogy to modern ambush
predators, would have detected prey on the basis of motion
parallax between prey and background (induced by either the
prey’s motion or the predator’s self motion). As in crocodilians,
the narrow BFoV might have provided allosauroids sufficient
binocular depth perception for judging prey distances and timing
attacks.
Or Snively et al (2019) regarding Tyrannosaurid's agility:
Quote:Tyrannosaurids consistently have agility index magnitudes twice those of allosauroids and some other theropods of equivalent mass, turning the body with both legs planted or pivoting over a stance leg. PhylANCOVA demonstrates definitively greater agilities in tyrannosaurids, and phylogeny explains nearly all covariance. Mass property results are consistent with those of other studies based on skeletal mounts, and between different figure-based methods (our main mathematical slicing procedures, lofted 3D computer models, and simplified graphical double integration).
On the other hand, the Allosauroid's lighter and more lightly built head may help it to move its head faster (due to lower inertia)
5: Anyway, i would place more weights on these factors when it comes to landing a "decisive bite" than having slightly longer skull... But anyway, it's up to you to decide which factors you think are relevant of course.
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)
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.
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
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?
5: My main point here was to make a case for carnosaurs against tyrannosaurs at parity; I have absolutely no idea where the myth of crushing bite>slicing bite stemmed from, and tyrannosaurids are often viewed as vastly superior parity fighters with no good evidence to back it up.
Carnivorous dinosaurs other than the famous t-rex and spinosaurus..
