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I remember that the Carnotaurus holotype had crocodile style face scales, but they were destroyed by the excavation. Is it likely that their Ceratosaur ancestors and/or other theropods like tyrannosaurs and raptors had the same style of face scales?

If Tyrannosaurus could not roar as depicted in the Jurassic movies, could it instead be able to create low frequency growls that could be considered comparable to infrasound in elephants? In a sense, rather than hear it's approach, you could feel it's presence.

When I saw Jurassic Park at the Royal Albert Hall, the roars themselves were not as loud as I would have liked, but the frequency for the growls and snarls were set so low I could feel the vibrations through the auditorium! This gave me an idea of how T. rexes could still be intimidating without being able to roar necessarily.

What would a baby Dimetrodon look like? I need help for something I'm writing.

No-one can answer any of my questions? I mean I know they're pretty large subjects but...

I tried to look into the Triassic-Jurassic extinction last night and spent literally two hours among several hundred page PDF research papers. Some of them tell among the lines that there is no particular evidence of individual dinosaur species dying in the extinction into the first stages of Jurassic, but all of those bits are very vague and some state mild contradictions. Then again, the whole extinction event itself isn't like P-T or K-T, where the biodiversity losses are plain obvious.

Nathanoraptor wrote:

What would a baby Dimetrodon look like? I need help for something I'm writing.

The following is the best I can do.

http://ashere.deviantart.com/art/Field-Sketches-of-Dimetrodon-grandis-538854707

https://chasmosaurs.blogspot.com/2015/06/the-finback-and-shark-process-blog.html

tigris115 wrote:

Did Dimetrodon and Edahrosaurus lack earholes?

Hope this helps: http://www.deviantart.com/art/Lend-Me-Your-Ears-658805912

What similarities and differences are there between a sauropod femur and a crocodile femur? I have to compare and contrast them for a university assessment.

Nathanoraptor wrote:

What similarities and differences are there between a sauropod femur and a crocodile femur? I have to compare and contrast them for a university assessment.

I'm pretty sure that sauropod femurs are more solidly built for land. Crocodiles are amphibious reptiles so they don't need femurs as thick. Not that they aren't thick in their own right, but sauropods are far larger and spend time on land far more so they need thick leg bones.

Has apatosaurine skeletons been found outside America? If not, why?

To the best of my knowledge no, but I wouldn't be surprised if one comes out of Portugal soon. I would imagine it's mostly a factor of fewer exploration in that age of materials outside of the American West.

But isn't Africa full of Late Jurassic fossils-those from the Tendaguru Formation-that are about the same age of those from the Morrison formation? I know that location must be dug out quite well but there must some other fossils still there not to mention other formations in Africa that have fossils from that age. If Diplococids like Barosaurus have been found in Africa, then it shouldn't be impossible to find an apatosaur there too.

I would agree that there are probably Apatosaurines in the Tendaguru, but to the best of my knowledge it has not been particularly well explored past the German expeditions. Bearing that in mind, there is probably much more to be found there. It is also possible that though the Tendaguru is from the appropriate time, it might not represent habitat that was accommodating to Apatosaurines as the Morrison appears to have been. The Tendaguru seems to have a lot more Macronian sauropods in it relative to the Diplodocids (almost an inverse of the general trend seen in the Morrison), so I don't think it is too unlikely that there is a habitat difference between the two areas.

Is the African Barosaurus still considered a species of Barosaurus or could we have the same situation like we had with Brachiosaurus and Giraffititan?

No, it is now classified as Tornieria africana.

What are the main differences between the two? Is Barosaurus larger then Tornieria like how Brachiosaurus is larger then Giraffititan?

From what I can tell, it was about the same size. A lot of the material was lost during Allied Bombing in WW2, the differences between it an Barosaurus are considerably more minute than between Brachiosaurus and Giraffititan.

Has the African species of Allosaurus been re-described as something else, or it is still considered as the African Allosaurus.

does anyone what some of the most common dinosaurs were? by that i mean which genera have the most known individuals?

Oshronosaurus wrote:

does anyone what some of the most common dinosaurs were? by that i mean which genera have the most known individuals?

I know many of the top of my head.

Triceratops (Very common. Triceratops skulls are considered fossils in and of themselves because so many have been found.)
Centrosaurus (Hundreds of these have been found. Far more then those of Triceratops.)
Edmontosaurus
Styracosaurus
Allosaurus
Protoceratops
Iguanodon
Hypsilophodon
Camarasaurus
Plateosaurus (A very common Late Triassic dinosaur.)

thanks for those, Rhedo  an excellent starting point. d'ya know any more? (i seem to remember reading that Tyrannosaurus is actually pretty common, too)

Oshronosaurus wrote:

thanks for those, Rhedo  an excellent starting point. d'ya know any more? (i seem to remember reading that Tyrannosaurus is actually pretty common, too)

While it's true that far more T. rex fossils have been found since 1990, I'm not sure if we can call it common. Maybe semi-common for now.

Here's more.

Albertosaurus/Gorgosaurus. I know the 2 were reclassified so I don't know which skeletons are which.
Apatosaurus
Maiasaura
Saurolophus, though mainly in China and Mongolia since the North American species is rarer.
Massospondylus
Ceratosaurus
Diplodocus

With all the semi-healed hadrosaur and Triceratops bones that prove that T. rex could hunt healthy prey, how did they escape in the first place? Was it simply because that T. rex was too focused on catching up that it didn't have time to bite with full/mostly full power?

Predators fail hunts for a number of reasons, and I doubt that we could ever know why a particular dinosaur escaped predation. Remember that these animals would be fighting back, and that's a lot of mass to throw around. Not to mention that if they were not alone it's very possible that they had assistance in escaping. This is especially true because any predator is taking a high risk of injury when it hunts, so T. Rex would have been very careful when engaged with another large animal.

I know that the shoulder blade and whatever other bones of Ultrasauros that were brachiosaurid, as well as its 90ft length were given to Brachiosaurus. But how big could it really get? If we have a 110 foot long Apatosaurus in Oklahoma, then a Brachiosaurus reaching that size really shouldn't be that unlikely.

Apparently the Ultrasauros scapula is actually slightly smaller than the original specimen. That being said, most our largest Brachiosaurus material (not sure about Giraffititan) is from a probably subadult. So larger sizes than the traditional estimates wouldn't be surprising.

Paleoman wrote:

Apparently the Ultrasauros scapula is actually slightly smaller than the original specimen. That being said, most our largest Brachiosaurus material (not sure about Giraffititan) is from a probably subadult. So larger sizes than the traditional estimates wouldn't be surprising.

When did that happen? And why are Brachiosaurus remains so rarer compared to Camarasaurus and the diplodocid family?

The info about the sizes is from the 2009 paper which separated Brachiosaurus and Giraffatitan. If I had to guess why Brachiosaurus are rarer in the Morrison, I would say it is probably due to a few factors. One, these guys were really big, even compared to their contemporaries, and might have been just a less numerous species. There is also the possibility that they weren't as prolific in the environment of the Morrison, and spent most of their time in other places.

Could the fetaherless arms of theropods be used like canards for running? Let me explain what that means, some jet fighters like the Eurofighter Typhoon and the Russian Su-34 Fullback fighter-bomber have canards between the cockpit and the main wings to enhance maneuverability. I've been wondering if theropod arms could have a similar function in some form.

That is a really interesting question, and it is underpinned by a lot of biomechanical issues. It would probably be dependent on forelimb length and flexibility. So, a T.rex obviously no, but something with longer arms... maybe. I think shoulder flexibility would be a key factor in this, and coelurosaurs had pretty flexible shoulders that could in some cases raise the arm to a horizontal angle.

You mentioned featherless arms, and to that aim I doubt they would function like a canard. Simply because they don't have a very big surface area. However, they might have been used to help maneuver through their inertia, but I don't know if they would have an appreciable influence compared to the much more massive tail.

Feathered arms are another story, they had enough surface area to be aerodynamically significant. But, I don't know if there would be a speed factor involved. What I mean by that, and I am far from a physicist, but I wonder if a dinosaur would have to be moving at a certain speed before the influence of the arms would be noticeable. If that is the case, then it would depend on what that speed was and which particular dinosaur was being looked at.

Paleoman wrote:

That is a really interesting question, and it is underpinned by a lot of biomechanical issues. It would probably be dependent on forelimb length and flexibility. So, a T.rex obviously no, but something with longer arms... maybe. I think shoulder flexibility would be a key factor in this, and coelurosaurs had pretty flexible shoulders that could in some cases raise the arm to a horizontal angle.

You mentioned featherless arms, and to that aim I doubt they would function like a canard. Simply because they don't have a very big surface area.  However, they might have been used to help maneuver through their inertia, but I don't know if they would have an appreciable influence compared to the much more massive tail.

Feathered arms are another story, they had enough surface area to be aerodynamically significant. But, I don't know if there would be a speed factor involved. What I mean by that, and I am far from a physicist, but I wonder if a dinosaur would have to be moving at a certain speed before the influence of the arms would be noticeable. If that is the case, then it would depend on what that speed was and which particular dinosaur was being looked at.

I figured that feathered arms, a la Velociraptor could. But I wasn't sure about others. Could feathered arms be used as speed brakes to help slow down running feathered dinosaurs like how parachutes slow down cargo that sliding forward in military drop offs?