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

[Verdugo]

(09-28-2019, 07:54 PM)tigerluver Wrote: For the second larger Giganotosaurus cited to be 8% larger by the original work, we can extrapolate this specimen's femoral circumference to be (520 * 1.08) 562 mm and femoral length to be (1365 * 1.08) 1474 mm. We can go through the aforementioned math again as follows with the larger Giganotosaurus as specimen 2:

Now I acknowledge Scott Hartman's estimate for the second Giganotosaurus being no more than 6.5% but his reasoning could be better explained before it's taken over the original work's determination. Persons et al. (2019) themselves do acknowledge that the holotype Giganotosaurus they used in their table is likely not the largest specimen for the species.

Regarding the 'larger' 8% Giganotosaurus specimen, Franoys has a say about it that you might want to consider:

*This image is copyright of its original author

It's needed to stress that the only thing associated with the 'larger' Giganotosaurus specimens is a fragmentary dentary bone, there are no other cranial or post-cranial materials associated with it whatsoever. So assuming that the 'larger' Giga also has 8% larger femur is logically un-sounded. Fragmentary pieces of bones don't scale isometrically in Dinosaurs nor in any Tetrapod, living or extinct, for that matter. Animals are not perfect clones or copy&paste of one another. It's perfectly normal for two human beings to be of similar height and weight and one has longer fingers or larger feet than the other. The same can be said for Dinosaurs. In fact, in some previous posts, Pckts even remarked that T-rex specimens might belong to different sub-species while they're merely just different specimens (based on our current knowledge). It's a clear example of why fragmentary pieces of bones simply do not scale isometrically in Dinosaur, even within the same species.

Said bone is not even 8% larger as per Franoys comment. It's only 8% longer simply because it's a more completed, better preserved piece of bone. While i do agree that no one knows how Hartman came up with his 6.5% assessment, given the fact that he's certified researcher and he has co-authored some peer-reviewed papers, i don't really mind taking his words for it. Therefore, the 6.5% by Hartman should be as generous and as liberal as anyone can give to that Giganotosaurus's specimen. MUCPV 95 surely does have too much unearned publicity, given just how unremarkable a specimen it really is. Reply

[tigerluver]

(10-01-2019, 03:25 AM)Verdugo Wrote:

(09-28-2019, 07:54 PM)tigerluver Wrote: For the second larger Giganotosaurus cited to be 8% larger by the original work, we can extrapolate this specimen's femoral circumference to be (520 * 1.08) 562 mm and femoral length to be (1365 * 1.08) 1474 mm. We can go through the aforementioned math again as follows with the larger Giganotosaurus as specimen 2:

Now I acknowledge Scott Hartman's estimate for the second Giganotosaurus being no more than 6.5% but his reasoning could be better explained before it's taken over the original work's determination. Persons et al. (2019) themselves do acknowledge that the holotype Giganotosaurus they used in their table is likely not the largest specimen for the species.

Regarding the 'larger' 8% Giganotosaurus specimen, Franoys has a say about it that you might want to consider:

*This image is copyright of its original author

It's needed to stress that the only thing associated with the 'larger' Giganotosaurus specimens is a fragmentary dentary bone, there are no other cranial or post-cranial materials associated with it whatsoever. So assuming that the 'larger' Giga also has 8% larger femur is logically un-sounded. Fragmentary pieces of bones don't scale isometrically in Dinosaurs nor in any Tetrapod, living or extinct, for that matter. Animals are not perfect clones or copy&paste of one another. It's perfectly normal for two human beings to be of similar height and weight and one has longer fingers or larger feet than the other. The same can be said for Dinosaurs. In fact, in some previous posts, Pckts even remarked that T-rex specimens might belong to different sub-species while they're merely just different specimens (based on our current knowledge). It's a clear example of why fragmentary pieces of bones simply do not scale isometrically in Dinosaur, even within the same species.

Said bone is not even 8% larger as per Franoys comment. It's only 8% longer simply because it's a more completed, better preserved piece of bone. While i do agree that no one knows how Hartman came up with his 6.5% assessment, given the fact that he's certified researcher and he has co-authored some peer-reviewed papers, i don't really mind taking his words for it. Therefore, the 6.5% by Hartman should be as generous and as liberal as anyone can give to that Giganotosaurus's specimen. MUCPV 95 surely does have too much unearned publicity, given just how unremarkable a specimen it really is.

Thank you, that gives better context to the situation. I was under the impression that the authors of the second Giganotosaurus made their assessment based on more than just the the absolute measurement of the fragment.  Nonetheless, within a species, a bigger skull is a safer bet to have a bigger femur and until proven otherwise with a full skeleton it is a fairer assessment in my opinion. From at least cats, I will admit mandible height is a very poor predictor of skull size however.

Regarding isometry and other methods, given that we are still basing all mass estimations based on bone measurements there is no other fair option. I agree that there is variation between individuals in bone measurement to mass, but by that logic Scotty, who in absolute terms is not much bigger than Sue but in mass scaling terms quite a bit heavier, wouldn't have been so special. Reply

[GuateGojira]

@tigerluver, this is all what is know for the specimen MUCPv-95:

*This image is copyright of its original author

As you can see, it is not too much, all the other calculations are pure speculation and sensacionalism, created even by the original authors. Even worst, as you know, there is a lot o variation on the size of skull in modern vertebrates, so the same obviously will apply to dinosaurs. In this case, this could be just a "normal sized" Giganotosaurus with a big jaw.

This is the holotype MUCPv-Ch 1:

*This image is copyright of its original author

Now you can compare them. But before to use the scale bar, take in count what Franois says in his post at DevianArt (in the image posted by @Verdugo). Reply

[GuateGojira]

(10-01-2019, 03:58 AM)tigerluver Wrote: Regarding isometry and other methods, given that we are still basing all mass estimations based on bone measurements there is no other fair option. I agree that there is variation between individuals in bone measurement to mass, but by that logic Scotty, who in absolute terms is not much bigger than Sue but in mass scaling terms quite a bit heavier, wouldn't have been so special.

In fact, "Scotty" was about the same size (if not slightly shorter) than "Sue". Just that some bones are wider which you know that it means that it was somewhat heavier. I think that both animals were over 12 m long (maybe up to 13 meters taking in count cartilage, flesh, fat and skin) and up to 9 tons, with "Scotty" porbably been the heaviest of the two by a short margin. Reply

[tigerluver]

(10-01-2019, 04:11 AM)GuateGojira Wrote: @tigerluver, this is all what is know for the specimen MUCPv-95:

*This image is copyright of its original author

As you can see, it is not too much, all the other calculations are pure speculation and sensacionalism, created even by the original authors. Even worst, as you know, there is a lot o variation on the size of skull in modern vertebrates, so the same obviously will apply to dinosaurs. In this case, this could be just a "normal sized" Giganotosaurus with a big jaw.

This is the holotype MUCPv-Ch 1:

*This image is copyright of its original author

Now you can compare them. But before to use the scale bar, take in count what Franois says in his post at DevianArt (in the image posted by @Verdugo).

The amount of fossil found in itself should not take away from the conclusions. If I were to show you half a lion mandible and a full skeleton of a leopard, it'd be safe to say how much bigger the lion is than the leopard despite the lion evidence being very fragmentary. What does take away from the conclusions is the lack of numerical comparison in the 1998 paper and then the subsequent issue of the second mandible being only 2% taller. Were the tooth diameters ever compared? Reply

[GuateGojira]

(10-01-2019, 04:56 AM)tigerluver Wrote: The amount of fossil found in itself should not take away from the conclusions. If I were to show you half a lion mandible and a full skeleton of a leopard, it'd be safe to say how much bigger the lion is than the leopard despite the lion evidence being very fragmentary. What does take away from the conclusions is the lack of numerical comparison in the 1998 paper and then the subsequent issue of the second mandible being only 2% taller.

Yes, but these are not diferences like between a lion an a leopard, this will be like a lion and a tiger, so closelly sized animals, but at the same time, so different in form (in the case of the dinosaurs, obviously). Plus, we need to add  the unknown anatomy of those animals that we can only infer how much heavy they were.

Franois have apoint, I a follow that line. Even Harman is doubthing of his previous estimations (although not entirely). Reply

[Spalea]

Allosaurus running as a modern felid... Why not but not very credible.

Reply

[Spalea]

Dilophosaurus: nice painting...

Reply

[DinoFan83]

Guanlong, the first tyrannosaurid. 3 meters, 70 kg, from China 160 million years ago
Who would have guessed this would evolve to Tyrannosaurus rex?

*This image is copyright of its original author

Reply

[Spalea]

Nice depiction of dilophosaurus... The ballerina's grace.

Reply

[Verdugo]

*This image is copyright of its original author

https://www.deviantart.com/robertfabiani/art/Acrocanthosaurus-Atokensi-641364742?src=MC_deviation_stack

Very beautiful artist rendition of Acrocanthosaurus. Probably in the top 3 largest Carnivores ever to walk North America. Reply

[Verdugo]

*This image is copyright of its original author

South America Speed Demon. Carnotaurus makes sure he never skips legs day
https://www.deviantart.com/robertfabiani/art/Carnotaurus-748089965 Reply

[DinoFan83]

Siats, a tyrannosauroid from North America 98 million years ago. Thought to have been 9-11 meters but still a juvenile!

*This image is copyright of its original author

Reply

[Spalea]

Dilophosaurus...

Reply

[Spalea]

Death an end of a myth... Velociraptor & Deinonichus reconstitution with latest scientific knowledge.

Reply