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

United Kingdom Spalea Offline
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" Three Kings: Tyrannosaurus, Zhuchengtyrannus & Tarbosaurus

by illustrator Mauricio Antòn

Tyrannosaurus is a genus of coelurosaurian theropod dinosaurs. The species Tyrannosaurus rex, often called T. rex or colloquially T-Rex, is one of the most well-represented of the large theropods. Tyrannosaurus lived throughout what is now western North America, on what was then an island continent known as Laramidia.
Height: 3.7 – 6.1 m
Mass: 4,500 – 14,000 kg

Zhuchengtyrannus is a genus of tyrannosaurid theropod dinosaur known from the Late Cretaceous period of Shandong Province, China. It belongs to the tyrannosaurinae subfamily, and contains a single species, Zhuchengtyrannus magnus.
Length: 10 – 12 m (Estimated)
Height: 4 m (At the hips)
Mass: 4,900 kg (Estimated)

Tarbosaurus is a genus of tyrannosaurid theropod dinosaur that flourished in Asia about 70 million years ago, at the end of the Late Cretaceous Period, considered to contain a single known species, Tarbosaurus bataar.
Length: 10 – 12 m
Mass: 4,000 – 5,000 kg (Adult) "


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Canada DinoFan83 Offline
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( This post was last modified: 10-04-2020, 03:05 AM by DinoFan83 )

Here's some food for thought on the obscure tibia of 'Allosaurus tendagurensis', which may be among the largest Jurassic theropods of all.

First off, its phylogeny. Mickey Mortimer suggests it to be a megalosauroid instead of an allosaurid or carcharodontosaurid as is commonly believed. This giant tibia being a megalosauroid is also consistent with the recent assignment of 'Megalosaurus ingens' teeth from the Tendaguru to Torvosaurus. Going by this, I think it's a reasonable bet that this tibia is Torvosaurus.
"Chure (2000) stated this specimen resembles abelisaurids because it lacks a strongly curved cnemial crest or incisura tibialis and has no posterior groove between the lateral and medial condyles, but differs from them in that the astragalus is not fused to it and the fibular crest is more distally placed. However, the depth of the incisura tibialis is uncertain since Rauhut (2011) indicates the low lateral projection distally may be due to erosion. Furthermore, the posterior groove is present and was merely not indicated by Janensch's dotted line in the reconstruction. It also lacks the distally expanded cnemial crest of ceratosaurs (Carrano et al., 2012). The distally placed fibular crest is a tetanurine synapomorphy (which is fully compatible with a lack of tarsal fusion), as noted by Rauhut. Within Tetanurae, the astragalar step excludes tendagurensis from Coelurosauria, but its more detailed affinities are unknown. The broad fibular crest is similar to Piatnitzkysaurus, Megalosaurus and metriacanthosaurines"
The tibia is about 91 cm long as preserved, and can be restored to either 98, 101, 108, or 110 cm. I'll scale all 4 in this post.

For length and mass, GetAwayTrike's Torvosaurus is a good basis. Greg Paul estimates a 9 meter long Torvosaurus at 2 tonnes, but based on comparisons between his and GetAwayTrike's skeletal, it looks to me as though GAT's would be about 1.5 tonnes. 
The Theropod Database lists the tibia of BYUVP 2002 at 72.5 cm, so this size tibia belongs to a 9 meter, 1.5 tonne torvosaur. The scalings are as follows.

98 cm length estimate: With the length estimate of 98 cm, the owner of the tibia ends up at 12.16 meters long and 3.7 tonnes in mass.
101 cm length estimate: With the length estimate of 101 cm, the owner of the tibia ends up at 12.54 meters long and 4.06 tonnes in mass.
108 cm length estimate: With the length estimate of 108 cm, the owner of the tibia ends up at 13.4 meters and 4.96 tonnes in mass.
110 cm length estimate: With the length estimate of 110 cm, the owner of the tibia ends up at 13.66 meters long and 5.24 tonnes in mass.

The mean length of these is about 12.94 meters, and the mean mass 4.5 tonnes. So this is undoubtedly a very large specimen for Torvosaurus, most likely larger than both Torvosaurus gurneyi and Edmarka rex.

One last note to make: This specimen of Torvosaurus may have had one of the longest and largest theropod skulls of all. The skull on GetAwayTrike's reconstruction for BYUVP 2002 is 115 cm long, and it isn't elongated and stretched out, it's quite robust and heavy. So based on that, the skull length of the owner of the tibia would have had a skull 155.4 to 160.2 cm long for the lower estimats, and 173.1 to 174.5 cm long for the upper estimate. This is right up there with the skulls of large Cretaceous theropods (such as Tyrannosaurus and large carcharodontosaurids for example, which are known for their skull size), and probably even bigger at the upper end!
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United Kingdom Spalea Offline
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" Velociraptor & Deinonichus reconstitution with latest scientific knowledge. "





And they became fat chickens... Frankly, the best vision I prefer of them is the Spielberg's (Jurassic Park reconstitution)...
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" Utahraptor Ambush ?

Artwork by Herschel Hoffmeyer
Utahraptor (meaning Utah's predator) is a genus of large dromaeosaurid dinosaur that lived in North America during the Early Cretaceous period. It was a heavy-built, ground-dwelling, bipedal carnivore. It contains a single species, Utahraptor ostrommaysi, which is the largest-known member of the family Dromaeosauridae.
The largest described U. ostrommaysi specimen (BYUVP 15465, referred by Erickson et al. 2009) is estimated to have reached up to 7 m (23 ft) long and somewhat less than 500 kg (1,100 lb) in weight, comparable to a polar bear in weight. In 2012, the paleontologist Thomas R. Holtz Jr. estimated its weight around 230 to 450 kg (500 to 1,000 lb), comparable to a grizzly bear. However, the 2001 Kirkland discovery indicates the species may be far heavier than previously estimated. In 2016 Rubén Molina-Pérez and Asier Larramendi estimated the largest specimen (BYU 15465) at 4.65 m (15.3 ft) long, 1.5 m (4.9 ft) tall at the hips and 280 kg (620 lb) in weight.
Although feathers have never been found in association with Utahraptor specimens, there is strong phylogenetic evidence suggesting that all dromaeosaurids possessed them."


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Canada DinoFan83 Offline
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Allosaurus jimmadseni by Andrey Atuchin

*This image is copyright of its original author
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( This post was last modified: 11-18-2020, 08:10 PM by DinoFan83 )

Here's some food for thought on Carcharodontosaurus: Contrary to popular belief, the only reason why SpinoInWonderland's Carcharodontosaurus is so much bigger than Franoys' is simply due to the fact that SpinoInWonderland's best fit between IPHG 1922 and SGM-DIN 1 results in a greater discrepancy than Franoys' - 19.2 vs 12.5 percent. Aside from that their skeletals are pretty much identical with the base - mostly Tyrannotitan and Giganotosaurus.
Heck, if you solely used Franoys' skeletal but used the 'best fit' between the 2 specimens of thedinorocker (26 percent larger), you'd get 13.44 meters and 9.35 tonnes for SGM-DIN 1. This should be an important consideration to anyone who thinks any Carcharodontosaurus bigger than Franoys' is inaccurate just because it is bigger.
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" Daspletosaurus horneri.

Artwork by Masato Hattori
Daspletosaurus (meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in western North America between about 77 and 74 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains two species. Fossils of the earlier type species, D. torosus, have been found in Alberta, while fossils of the later second species, D. horneri, have been found only in Montana. A possible third species, also from Alberta, awaits formal identification. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex. Like most tyrannosaurids, Daspletosaurus was a multi-tonne bipedal predator equipped with dozens of large, sharp teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera.
While very large by the standard of modern predators, Daspletosaurus was not the largest tyrannosaurid. Adults could reach a length of 8–9 meters (26–30 ft) from snout to tail. Mass estimates have centered on 2.5 metric tons (2.8 short tons), but have ranged between 1.8 and 3.8 metric tons (2.0 and 4.2 short tons). "


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( This post was last modified: 12-09-2020, 07:57 AM by DinoFan83 )

Here is some food for thought on Megalosaurus: It would appear that judging by the proportions of relatives, this animal is a lot less 'vanilla' than many of us think.

Going by GetAwayTrike's skeletal, this is a fairly large skulled animal - for the largest specimen (BMNH R1101, an 83.2 cm ilium), a 115 cm long skull on an animal that appears to be close to 2 tonnes based on a GDI of a non cross-scaled model (the model was 1.9 tonnes but the increased size of the arms and head bring it up to 2). Since all known cranial material was found in isolation and it is not known what size Megalosaurus it belongs to, the skull in GetAwayTrike's skeletal was apparently cross scaled from his Torvosaurus using the ratio of a postcranial element to skull size, but I don't know exactly what he had done as from what I can see, Torvosaurus' proportions result in larger skulls than how he depicted, even if it is fairly large already. 
For example, pubis length. According to the Theropod Database, the pubis of the Torvosaurus holotype is 73.6 cm long compared to a 115 cm skull following GAT's skeletal. Using the scalebar in GAT's Megalosaurus, the pubis length ends up at about 89.9 cm, thus a skull length of 140.4 cm using the pubis to skull ratio of Torvosaurus as opposed to 115. 

Another thing is the forearms - as with the cranial material, the forearm material for Megalosaurus has been found isolated and it's not given that it was from an animal similarly sized to BMNH R1101, even though GAT composited it into the largest individual unlike what he did with the skull.
Therefore, a megalosaur that preserves very complete arm material and associated postcrania (Afrovenator) is a good choice to use as a base. Following the Theropod Database, the Afrovenator holotype had a 40 cm humerus compared to a 56.7 cm ilium, which would result in a 58.7 cm long humerus for BMNH R1101. Also note the size of the very large thumb claw; with this cross scaling, it would have reached 45 cm along the curve.

To put all that into perspective, this is what such an animal would have looked like. I unfortunately cannot yet articulate these images in GIMP, but on the left and center is what the head and body would look like following the above and on the right is the forearm size that this animal would have had. 

*This image is copyright of its original author

These in my opinion make for a set of proportions reminiscent of a big game hunter that needs as much weaponry as possible with which to bring down large prey. Provided the cross scaling is roughly accurate, it would have had a very massive, robust head and very lethal bite to boot, but also quite large, robust, and vicious clawed forelimbs. No other carnivorous dinosaur in this weight class that I am aware of would have had this combination of such a big head together with big arms.
But it doesn't stop there; in fact, this Megalosaurus would have had proportionally more robust forelimbs than a grizzly bear (which are known for being quite robust for a carnivoran, so its forearms would be even more proportionally robust than other carnivorans)!
Based on Campione and Evans (2012) supplementary info, a 436 kg grizzly bear has a 40.1 cm humerus 14.6 cm in circumference. Meanwhile, going by the supplementary material from Benson (2014), a 38.8 cm Megalosaurus humerus is 19.1 cm in circumference, meaning a 58.7 cm Megalosaurus humerus would be about 28.9 cm in circumference.
To be at parity with the megalosaur, the bear would need to be 66.2% greater in linear dimensions (436(1.662)^3=2000), and at parity, not only is the bear's humerus only about 13.5% longer than those of the megalosaur, it is also far more gracile, with a humerus circumference about 19.2% smaller. I find that very impressive; this cross-scaled Megalosaurus not only has a skull over 2.4 times the length of that of an equivalently sized grizzly (but that's to be expected), it rivals or outclasses the bear in the forearm department too.
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johnny rex Offline
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(09-24-2020, 08:12 AM)DinoFan83 Wrote: Here is some food for thought on Megalosaurus: It would appear that judging by the proportions of relatives, this animal is a lot less 'vanilla' than many of us think.

Going by GetAwayTrike's skeletal, this is a fairly large skulled animal - for the largest specimen (BMNH R1101, an 83.2 cm ilium), a 115 cm long skull on an animal that appears to be close to 2 tonnes based on eyeballing with many volumetric estimates. Since all known cranial material was found in isolation and it is not known what size Megalosaurus it belongs to, the skull was apparently cross scaled from his Torvosaurus using the ratio of a postcranial element to skull size, but I don't know exactly what he had done as from what I can see, Torvosaurus' proportions result in larger skulls than how he depicted, even if it is fairly large already. 
For example, using pubis length to scale. According to the Theropod Database, the pubis of the Torvosaurus holotype is 73.6 cm long compared to a 115 cm skull following GAT's skeletal. Using the scalebar in GAT's Megalosaurus, the pubis length ends up at about 89.9 cm, thus a skull length of 140.4 cm using the pubis to skull ratio of Torvosaurus as opposed to 115. 

Another thing is the forearms - as with the cranial material, the forearm material for Megalosaurus has been found isolated and it's not given that it was from an animal similarly sized to BMNH R1101, even though GAT composited it into the largest individual unlike what he did with the skull.
Therefore, a megalosaur that preserves very complete arm material and associated postcrania (Afrovenator) is a good choice to scale from. Following the Theropod Database, the Afrovenator holotype had a 40 cm humerus compared to a 57 cm ilium, which would result in a 58.4 cm long humerus for BMNH R1101.

To put all that into perspective, this is what such an animal would have looked like. I unfortunately cannot yet articulate these images in GIMP yet but on the left and center is what the head and body would look like following the above scaling (by GetAwayTrike), and on the right is the forearm size (from Scott Hartman) that this animal would have had with the cross scaling.

*This image is copyright of its original author

These in my opinion make for a set of proportions reminiscent of a big game hunter that needs as much weaponry as possible with which to bring down large prey. Provided the cross scaling is roughly accurate, it would have had an IMMENSE head and very lethal bite, but also quite large, robust, usable, and damaging forelimbs. No other carnivorous dinosaur in this weight class that I am aware of would have had this combination of such a big head together with big arms.

Do you have any idea about the skull width of Megalosaurus?
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( This post was last modified: 11-12-2020, 11:55 PM by DinoFan83 )

(09-24-2020, 01:18 PM)johnny rex Wrote:
(09-24-2020, 08:12 AM)DinoFan83 Wrote: Here is some food for thought on Megalosaurus: It would appear that judging by the proportions of relatives, this animal is a lot less 'vanilla' than many of us think.

Going by GetAwayTrike's skeletal, this is a fairly large skulled animal - for the largest specimen (BMNH R1101, an 83.2 cm ilium), a 115 cm long skull on an animal that appears to be close to 2 tonnes based on eyeballing with many volumetric estimates. Since all known cranial material was found in isolation and it is not known what size Megalosaurus it belongs to, the skull was apparently cross scaled from his Torvosaurus using the ratio of a postcranial element to skull size, but I don't know exactly what he had done as from what I can see, Torvosaurus' proportions result in larger skulls than how he depicted, even if it is fairly large already. 
For example, using pubis length to scale. According to the Theropod Database, the pubis of the Torvosaurus holotype is 73.6 cm long compared to a 115 cm skull following GAT's skeletal. Using the scalebar in GAT's Megalosaurus, the pubis length ends up at about 89.9 cm, thus a skull length of 140.4 cm using the pubis to skull ratio of Torvosaurus as opposed to 115. 

Another thing is the forearms - as with the cranial material, the forearm material for Megalosaurus has been found isolated and it's not given that it was from an animal similarly sized to BMNH R1101, even though GAT composited it into the largest individual unlike what he did with the skull.
Therefore, a megalosaur that preserves very complete arm material and associated postcrania (Afrovenator) is a good choice to scale from. Following the Theropod Database, the Afrovenator holotype had a 40 cm humerus compared to a 57 cm ilium, which would result in a 58.4 cm long humerus for BMNH R1101.

To put all that into perspective, this is what such an animal would have looked like. I unfortunately cannot yet articulate these images in GIMP yet but on the left and center is what the head and body would look like following the above scaling (by GetAwayTrike), and on the right is the forearm size (from Scott Hartman) that this animal would have had with the cross scaling.

*This image is copyright of its original author

These in my opinion make for a set of proportions reminiscent of a big game hunter that needs as much weaponry as possible with which to bring down large prey. Provided the cross scaling is roughly accurate, it would have had an IMMENSE head and very lethal bite, but also quite large, robust, usable, and damaging forelimbs. No other carnivorous dinosaur in this weight class that I am aware of would have had this combination of such a big head together with big arms.

Do you have any idea about the skull width of Megalosaurus?

I would expect something similar to tyrannosaurids for the most part, but without the super wide rear portion. This is what that looks like, credit to GAT for the Megalosaurus skull and dorsal view is modified from theropod1's Tyrannosaurus skull.

*This image is copyright of its original author
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johnny rex Offline
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(09-24-2020, 03:23 PM)DinoFan83 Wrote:
(09-24-2020, 01:18 PM)johnny rex Wrote:
(09-24-2020, 08:12 AM)DinoFan83 Wrote: Here is some food for thought on Megalosaurus: It would appear that judging by the proportions of relatives, this animal is a lot less 'vanilla' than many of us think.

Going by GetAwayTrike's skeletal, this is a fairly large skulled animal - for the largest specimen (BMNH R1101, an 83.2 cm ilium), a 115 cm long skull on an animal that appears to be close to 2 tonnes based on eyeballing with many volumetric estimates. Since all known cranial material was found in isolation and it is not known what size Megalosaurus it belongs to, the skull was apparently cross scaled from his Torvosaurus using the ratio of a postcranial element to skull size, but I don't know exactly what he had done as from what I can see, Torvosaurus' proportions result in larger skulls than how he depicted, even if it is fairly large already. 
For example, using pubis length to scale. According to the Theropod Database, the pubis of the Torvosaurus holotype is 73.6 cm long compared to a 115 cm skull following GAT's skeletal. Using the scalebar in GAT's Megalosaurus, the pubis length ends up at about 89.9 cm, thus a skull length of 140.4 cm using the pubis to skull ratio of Torvosaurus as opposed to 115. 

Another thing is the forearms - as with the cranial material, the forearm material for Megalosaurus has been found isolated and it's not given that it was from an animal similarly sized to BMNH R1101, even though GAT composited it into the largest individual unlike what he did with the skull.
Therefore, a megalosaur that preserves very complete arm material and associated postcrania (Afrovenator) is a good choice to scale from. Following the Theropod Database, the Afrovenator holotype had a 40 cm humerus compared to a 57 cm ilium, which would result in a 58.4 cm long humerus for BMNH R1101.

To put all that into perspective, this is what such an animal would have looked like. I unfortunately cannot yet articulate these images in GIMP yet but on the left and center is what the head and body would look like following the above scaling (by GetAwayTrike), and on the right is the forearm size (from Scott Hartman) that this animal would have had with the cross scaling.

*This image is copyright of its original author

These in my opinion make for a set of proportions reminiscent of a big game hunter that needs as much weaponry as possible with which to bring down large prey. Provided the cross scaling is roughly accurate, it would have had an IMMENSE head and very lethal bite, but also quite large, robust, usable, and damaging forelimbs. No other carnivorous dinosaur in this weight class that I am aware of would have had this combination of such a big head together with big arms.

Do you have any idea about the skull width of Megalosaurus?

I would expect something similar to tyrannosaurids for the most part, but without the super wide rear portion. This is what that looks like, credit to GAT for the Megalosaurus skull and dorsal view is modified from theropod1's Tyrannosaurus skull.

*This image is copyright of its original author


Edit: here's some food for thought for anyone reading this post. With the adjusted arms and head, I would expect the Megalosaurus to be about 2.2 tonnes. Following the data from Benson (2014) supplementary material (38.8 cm humerus, 19.1 cm circumference), and the supplementary data from Campione and Evans 2012 (a 434 kg grizzly bear with a 14.6 cm circumference humerus), this means that this cross scaled Megalosaurus would have had arms proportionally more robust than a grizzly (and they are known for being robust for a bear) by 17.7 percent.

If Megalodon have similar bizygomatic to Torvosaurus, with skull length around 115 cm and more I think the skull width will be around 40 cm or a little bit more. I just saw a picture of a Torvosaurus skull from the front view by using Google search engine so I imagine the skull width is something around 40 cm or a little bit more. 

I believe Megalosaurids, coupled with huge skulls and large clawed arms, are formidable predators. I imagine if they live alongside the prehistoric mammalian predators, such as the prehistoric bears and big cats, the Megalosaurids will tend to dominate them especially over preys or direct confrontations.
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( This post was last modified: 10-04-2020, 09:25 PM by DinoFan83 )

(09-24-2020, 08:14 PM)johnny rex Wrote:
(09-24-2020, 03:23 PM)DinoFan83 Wrote:
(09-24-2020, 01:18 PM)johnny rex Wrote:
(09-24-2020, 08:12 AM)DinoFan83 Wrote: Here is some food for thought on Megalosaurus: It would appear that judging by the proportions of relatives, this animal is a lot less 'vanilla' than many of us think.

Going by GetAwayTrike's skeletal, this is a fairly large skulled animal - for the largest specimen (BMNH R1101, an 83.2 cm ilium), a 115 cm long skull on an animal that appears to be close to 2 tonnes based on eyeballing with many volumetric estimates. Since all known cranial material was found in isolation and it is not known what size Megalosaurus it belongs to, the skull was apparently cross scaled from his Torvosaurus using the ratio of a postcranial element to skull size, but I don't know exactly what he had done as from what I can see, Torvosaurus' proportions result in larger skulls than how he depicted, even if it is fairly large already. 
For example, using pubis length to scale. According to the Theropod Database, the pubis of the Torvosaurus holotype is 73.6 cm long compared to a 115 cm skull following GAT's skeletal. Using the scalebar in GAT's Megalosaurus, the pubis length ends up at about 89.9 cm, thus a skull length of 140.4 cm using the pubis to skull ratio of Torvosaurus as opposed to 115. 

Another thing is the forearms - as with the cranial material, the forearm material for Megalosaurus has been found isolated and it's not given that it was from an animal similarly sized to BMNH R1101, even though GAT composited it into the largest individual unlike what he did with the skull.
Therefore, a megalosaur that preserves very complete arm material and associated postcrania (Afrovenator) is a good choice to scale from. Following the Theropod Database, the Afrovenator holotype had a 40 cm humerus compared to a 57 cm ilium, which would result in a 58.4 cm long humerus for BMNH R1101.

To put all that into perspective, this is what such an animal would have looked like. I unfortunately cannot yet articulate these images in GIMP yet but on the left and center is what the head and body would look like following the above scaling (by GetAwayTrike), and on the right is the forearm size (from Scott Hartman) that this animal would have had with the cross scaling.

*This image is copyright of its original author

These in my opinion make for a set of proportions reminiscent of a big game hunter that needs as much weaponry as possible with which to bring down large prey. Provided the cross scaling is roughly accurate, it would have had an IMMENSE head and very lethal bite, but also quite large, robust, usable, and damaging forelimbs. No other carnivorous dinosaur in this weight class that I am aware of would have had this combination of such a big head together with big arms.

Do you have any idea about the skull width of Megalosaurus?

I would expect something similar to tyrannosaurids for the most part, but without the super wide rear portion. This is what that looks like, credit to GAT for the Megalosaurus skull and dorsal view is modified from theropod1's Tyrannosaurus skull.

*This image is copyright of its original author


Edit: here's some food for thought for anyone reading this post. With the adjusted arms and head, I would expect the Megalosaurus to be about 2.2 tonnes. Following the data from Benson (2014) supplementary material (38.8 cm humerus, 19.1 cm circumference), and the supplementary data from Campione and Evans 2012 (a 434 kg grizzly bear with a 14.6 cm circumference humerus), this means that this cross scaled Megalosaurus would have had arms proportionally more robust than a grizzly (and they are known for being robust for a bear) by 17.7 percent.

1: If Megalodon have similar bizygomatic to Torvosaurus, with skull length around 115 cm and more I think the skull width will be around 40 cm or a little bit more. I just saw a picture of a Torvosaurus skull from the front view by using Google search engine so I imagine the skull width is something around 40 cm or a little bit more. 

2: I believe Megalosaurids, coupled with huge skulls and large clawed arms, are formidable predators. I imagine if they live alongside the prehistoric mammalian predators, such as the prehistoric bears and big cats, the Megalosaurids will tend to dominate them especially over preys or direct confrontations.
1: Yes, I think that's a reasonable length to width ratio. It is surprisingly consistent with what you get using a Tyrannosaurus-like width minus the rear portion.

2: I feel the same way as you do about that - I in fact think that megalosaurids could be the most formidable predatory terrestrial vertebrates relative to their size, because no other predator of any kind has such a massive skull combined with large and powerful clawed forearms and good stamina.
As for the mammalian carnivores, I also agree. If you were to place these large and extraordinarily well armed animals in the same ecosystem as the ancient mammalian predators (such as the Oligocene of Asia or the Miocene/Pleistocene of North America), the large megalosaurids would have outcompeted the mammals quickly, and especially dominating them in direct confrontations over prey or really anything at all.
To put that into perspective, here is how the skull and limbs of an equivalently sized short faced bear (credit to the Alaska gov't) and Megalosaurus (credit to GetAwayTrike and Scott Hartman) compare:

*This image is copyright of its original author

As you can see, not only is the bear completely outclassed in the jaws department, the megalosaur would be able to give it a run for its money in terms of forearms given how strong its forearms are. The short faced bear would have been the apex predator of its time, but I see it getting dominated and outcompeted in just about every confrontations if large megalosaurids were in the environment. Same goes for other apex mammalian predators.
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( This post was last modified: 09-26-2020, 11:47 AM by DinoFan83 )

Yutyrannus. This basal tyrannosauroid is most well known for the fact that it most likely had a coating of feathers, but there are some things about it that tend to get overlooked. Namely, the large size of its arms and head as well as the allosauroid-like crests on its skull.

Here are Scott Hartman's restorations of the skulls of specimens ZCDM V5001 and ELDM V10001; these show off the impressive head crests nicely, as well as the massive and deep nature of the skull.

*This image is copyright of its original author


And here is Greg Paul's skeletal, in which the proportionally large arms and head are very apparent.

*This image is copyright of its original author

Side note: Yutyrannus has, compared to its much more famous relative Tyrannosaurus, a proportionally larger head as well as proportionally and absolutely larger arms than any Tyrannosaurus specimen (though perhaps that second point is not so much of a surprise). This does show that at least basal tyrannosauroids were probably doing some evolutionary experimenting before their more famous and more specialized descendants evolved.
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( This post was last modified: 10-29-2020, 04:44 AM by DinoFan83 )

For those who don't know about this species, here's a post on Concavenator, one of the best preserved and most unusual of the carcharodontosaurids known thus far.
There are a number of noteworthy and interesting things about this species:

-Its small size. Greg Paul (2016) estimates it at 320 kg, easily surpassed 30 to 33-fold or more by some of its larger relatives like Carcharodontosaurus, Giganotosaurus, and Mapusaurus.

-Its neural spines. As can be seen further down the post, the neural spines close to the hips suddenly experience a significant rise in height, a dip, and then another small rise, creating a concave hump of neural spines on the animal's back that are its namesake. These are not pathological nor an artifact of taphonomy to my knowledge, and some things they could have been used for are display, species recognition, or thermoregulation.

-Its completeness and excellent preservation. The Concavenator holotype (MCCM-LH 6666) is at a similar level of completeness to the infamously complete Tyrannosaurus specimen Sue, as Greg Paul's skeletal shows.


*This image is copyright of its original author

What's more, it's so well preserved it even has some skin impressions, such as crocodilian-like scales on the underbelly and large scutes on the lower legs.

-Its ulnar bumps. A series of bumps along the holotype's ulna have been interpreted by the original authors as evidence for a line of quill knobs, and they theorized that Concavenator could have been proof that feathers and quills evolved earlier in theropods than previously thought. However, there have been some counter-proposals to this.
(Although his blogpost about this doesn't appear to exist anymore), Darren Naish has argued that there are numerous factors that support the ulnar bumps as part of an intermuscular line instead of evidence for quill knobs, and Mickey Mortimer has independently come to that conclusion as well using modern alligators as a guide. Furthermore, Andrea Cau also raises a number of points why Concavenator most likely didn't have quills/feathers, and I think I agree with all of them given that (as was stated in the links) not only are the ulnar bumps wrongly positioned on the ulna to be quill knobs, they are very differently spaced from the quill knobs of species that we know had feathers, myological comparison with modern relatives easily show how the bumps coincide to an intermuscular line, and phylogenetics make it very unlikely that a carcharodontosaurid would have had quills/feathers in the first place.

-Its unexpected morphology given its phylogeny relative to other carcharodontosaurids. Concavenator is often recovered as a basal carcharodontosaurid closely related to animals like Neovenator and Acrocanthosaurus, who are often noted not to be as big headed relative to their size as giganotosaurines like Giganotosaurus or Mapusaurus. However, despite its close relation to these animals, the proportional size of Concavenator's skull seems to blow not only its relatives but every giganotosaurine ever discovered so far completely out of the water. 
Going off of Ville Sinkkonen's skeletal, the skull is 71 cm long, which would equate to a 320 kg animal possessing, in absolute terms, a skull 11 cm larger than that of a 2 tonne hippo. Relative to its size, Concavenator is among the most big headed theropods of all that have been found so far.
Now, I know what you may be thinking: that neither of the skeletals I have shown so far seen to suggest the animal's skull being that big relative to its body size. It should be noted, however, that given measurements for other bones found in the literature, Paul's and Sinkkonen's skeletals of this animal either have the skull too small despite the postcrania being appropriately sized, or have the postcrania too large despite the skull being appropriately sized. Case in point, according to Benson et al. 2014, the Concavenator holotype's femur is 55 cm long, therefore one could then expect a skull length to femur length ratio of slightly above 1.29. However, the scalebar in Ville Sinkkonen's skeletal yields 71.5 cm for femur length, equating to a skull length to femur length ratio of 0.979 and a possibility of the postcrania being oversized 30 percent relative to the skull. Greg Paul's skeletal shows something very similar; given the reported 55 cm femur length, the skull length of his skeletal ends up at about 50.3 cm as opposed to 71 cm, therefore it seems to be undersized by about 39.3 percent. Why both Paul and Sinkkonen have the skulls so undersized I am not sure, but at least the mounted skeletons (photo by Kumiko) do a very good job of showing how large the head is relative to body size.


*This image is copyright of its original author

And here is a life restoration by Durbed on Deviantart: https://www.deviantart.com/durbed/art/Co...-262819757


*This image is copyright of its original author


I hope we end up finding more fossils of this amazing theropod!
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( This post was last modified: 11-19-2020, 08:35 AM by DinoFan83 )

Deleted my old post on this as it needed quite a bit of revision. 

In discussions about which theropods were among the largest known, megaraptorans are almost never present. With Siats possibly not being a member of the group, Osteoporosia being unreliable to the extreme, and Chilantaisaurus most likely not being much larger than 2-3 tonnes, even the largest members tend to be left out of discussions to make way for more famous giant theropods like giant tyrannosaurids, giant carcharodontosaurids, and giant spinosaurids .
However, this is very likely unjustified given the size of some specimens that are thus far unnamed (but may belong to known species*); these are very likely elligible to be among the largest tyrannosauroids of all, right up there with the famous giant tyrannosaurids.  

Case in point: MCF-PVPH 418.

Reported in Coria et al. 2004 as well as Baiano and Coria (2018), it is the centrum of an anterior dorsal vertebra, and is 11 cm long. The authors suggested this bone could belong to the biggest megaraptoran specimen ever found, and it seems that if the megaraptoran with the most complete series of dorsal vertebrae in 1 animal (Aerosteon) is anything to go by, they were right on the money.
The Theropod Database lists the 4th dorsal (which is the most similar dorsal that Aerosteon preserves to the giant dorsal in question and is therefore most likely the best to size up the giant dorsal with) as 7.1 cm long - substantially smaller than that of MCF-PVPH 418. And Aerosteon itself is no slouch sizewise - it would have been anywhere from 8.3 meters (PWNZ3R-Dragon) to 9.5 meters (Sereno et al. 2008) and 1.8 tonnes (PWNZ3R-Dragon's skeletal) to 3 tonnes (Thomas Holtz, the estimation is rhino size giving a mean of 3 tonnes in a range of 2-4), giving us a mean of of 8.8 meters long and 2.4 tonnes.   

So how gigantic exactly, you may ask, would this giant megaraptoran then be?  

Going off of an Aerosteon this size having a 7.1 centimeter long anterior dorsal, MCF-PVPH 418 ends up 13.6 meters long and 8.9 tonnes in mass. That's definitely keeping pace with the large tyrannosaurids of the Late Cretaceous, and is in fact a serious contender to significantly outsize even the largest of them, being 2.9 tonnes larger than the average T. rex and a full tonne heavier than my mean estimation of 7.9 tonnes for Sue (which was, to my knowledge, previously tied with David Hone's T. zhuchengensis dorsal as the largest tyrannosauroid known thus far). 
It also stacks up favorably with other giant theropods from South America, being very similar in size to my estimations of the average sizes for known specimens of Giganotosaurus and Mapusaurus/Giganotosaurus roseae, and seems to be even larger than another giant carcharodontosaurid, the 7+ tonne Tyrannotitan, when going on known specimens. Finally, this giant dorsal seems to be significantly bigger than any abelisaurid or ceratosaur from South America so far, so with all the above in mind I think we can safely consider this specimen among the largest of South American theropods assuming geometric similarity with Aerosteon is a safe bet.
Do note, however, that there is a lot of margin for error until a more complete skeleton is found - no estimation for this animal is to be taken as definitive for the time being given the sparse remains.

If this is anything to go by, it seems that, contrary to popular belief, the largest tyrannosauroids weren't necessarily just the derived tyrannosaurids.

*It should be noted that MCF-PVPH 418 comes from the Bajo de la Carpa Formation, the same rocks that produced another large-bodied megaraptoran, Tratayenia. The holotype of Tratayenia is similar in size to the holotype of Aerosteon going by the measurements at the Theropod Database, but the holotype was not fully grown so it could be that MCF-PVPH 418 is an adult specimen for Tratayenia. This cannot be confirmed or disproved until there is overlap in material (there is currently none given that Tratayenia preserves no anterior dorsals), but I find it likely to be the case given the already reasonably large size of the Tratayenia holotype, it not being fully grown, and the difficulty 2 species of megaraptoran would have coexisting.
If this theory is correct, this would most likely make Tratayenia the largest known tyrannosauroid based on known specimens, seemingly larger than even the largest derived tyrannosaurids as was gone over above, and among the largest known theropods of all. To have very large megaraptorans in South America is not surprising in the least - they seem to have already been dominant over their major competitors (the abelisaurids) after the extinction or decline of carcharodontosaurids, and there was nothing stopping them to get big as the carcharodontosaurids had. 
I can only imagine what a fierce animal this megaraptoran have been - quite fast for its size, deadly jaws, and huge claws. And that's all on an animal the size of a large elephant.
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