Mapusaurus roseae versus Tyrannotitan chubutensis

[theropod]

There wasn't much to improve, except for size, which is why sauropods and carcharodontosaurs grew so bit; sauropods relied on size to defend themselves, carcharodontosaurs already had the weapons needed and only increased size. Unless the sauropods suddenly evolved thagomizers such as the ones seen in Sspinophorosaurus, but there's no evidence for that.
If the prey changed, the change in the predator would help against that specific kind of prey, not necessarily against another predator, it is an adaption, not a general improvement.

[Grey]

An adaption in a context of potentially brutal confrontations with giants preys. Depending which one, the improvement in the evolution against larger and thougher preys would have an impact in hypothetical inter-specific conflicts with others predators.

The larger size of Mapusaurus is already a suggestion of this evolution toward larger sizes, and there are likely others factors that count, in behavorial and tactical skills and perhaps in physical features (jaws strength, speed, reflex, senses...).

[theropod]

There is no reason to suspect this, both probably hunted physiologically similar prey, Mapusaurus was just a little larger.
African lions are not superior over cave lions at parity because they are extant, are they? We don't really have anything to base supposedly superior fighting ability on, there is no basis for proportionally more challenging preys in M. roseae.
And jaw-strenght is not a factor in carnosaurs.

EDIT: It’s actually a good question if it was larger on average. That depends on the age distributions represented by the Mapusaurus specimens and the two Tyrannotitan types, as well as on the exact size of all of them. My merely considering the largest specimens for both is too simplistic in this case, I apologise.

[Grey]

Even so, I won't rule out the fact that this is his direct relative, that lived in the same location but millions years later so that it was most likely a more sophisticated version. The larger size is already an indicator.

The cave lion is a subspecies that did not live in the same environment and in the same region. The analogy does not stand.

[Life]

Evolutionary processes are continuous but they do not necessarily lead to relatively greater predators with passage of time. These processes just determine what species would be adequate for what particular environment; biological adaptations and changes are dependent upon this purpose.

As an example: Put a gigantic theropod in an environment inhabited by large modern herbivores and we may have an interesting food-chain in the making. Dinosaurs had proven to be highly-adaptable animals in history. If it weren't for that comet impact, dinosaurs would still have been ruling the world today.

Yes, intelligence is one particular trait which has been expanded upon by evolutionary processes since the first organism. However, all evolutionary processes are very slow to make noticeable difference.

Both of these dinosaurs lived during Early Cretaceous epoch (correct me, if I am wrong), so intelligence isn't going to be a (major) deciding factor. In-fact, intelligence isn't failure-proof trait at all.

Gigantic theropods were very strong and heavily armed in general; IMO, these monsters packed the capability to severely harm or even kill each other regardless of species and vice versa (should they ever meet).

[theropod]

I mostly agree with life's post, but some points;

-the chicxulub impact is thought to have been from a meteorite, and most books I read on the subject agree it wasn't the primary factor in the extinction of non-avian dinosaurs
-intelligence-increase isn't a constant during evolution, many groups that were comparatively intelligent for sure died out while others that were less so continued to exist and themselves evolved
-intelligence has little bearing on fights unless differences are huge (human/ant)

Grey: Larger size is merely what it is, larger size. No indicator of sophistication whatsoever, and sophistication has no proper scientific definition or relation to physiology. Even if Mapusaurus did somehow get better, which is not indicated, the few million years between them wouldn't make much of a difference. But these are two animals hunting very similar prey, one a bit larger than the other, with no other notable differences. Being a slightly younger, more derived member of the same taxon doesn't have any direct functional implications.

[gigadino96]

I'll bump up this thread as I realised that both these animals reached the same size.
As I've already said on 'Giant Theropods Overview Thread', MPEF-PV 1157 likely reached ~13 m or so. What about Mapusaurus? I know that there is a specimen 10 % larger than MUCPV-ch1 (even though it's only a pubic shaft), but, according to Sinkonnen's Mapusaurus, the latter had a proportionally longer pubis. This would mean that Mapusaurus largest specimen was less than 10 % bigger, it would instead be 13.3 m long, wich is roughly 13 m. So, both reached a similar lenght (so it's likely that they reached a similar mass as well), thus it's a 50/50.

[Deleted]

About the same dino. 50/50 at parity

[dinosauria101]

I favor Mapusaurus, due to its size advantage but this is a very close fight.