All posts by Marshsky123

@TorvosaurusTheTanneri Oh don't get me wrong I'm not trying to propose anything concrete here. A horizontal orientation was probably their default posture. I am just exploring the range of flexibility of their posture. If theropods couldn't move or could only hobble around awkwardly in a non-horizontal posture, then their arms would be completely useless due to their limited anterior range of movement, and they would have no reason to have them. This would fly if the only theropods we knew about were T. Rex and Abelisaurids, but then you have theropods like allosaurus with highly developed raptorial arms that were clearly used for something.

Assuming these forelimbs were used for handling prey (probably given their "contract"-ey movement) then looking at the body proportions of an Allosaurus, then it would require a lot of awkward posturing and uncomfortable neck bending to even bring the prey to its arms given the limited anterior range of motion, to the point where just using the mouth would be easier. Clearly, to those theropods that retained large, raptorial forelimbs, they must have been useful, otherwise they would not have had the morphology they did.

@TorvosaurusTheTanneri I see your point but at the same time the fact that almost every single theropod in this pose which looks bizarre when viewed horizontally makes me seriously consider this posture. The only one that doesn't have swept back legs is the fossil of sinosauropteryx prima (chen et al., 1998) and that one has a sharply arched tail. Like I said, herbivore fossils either have a tail with a lazier arch (camarasaurus) or no arch whatsoever (juvenile triceratops in the duelling dinosaur fossil). I even made a pencil sketch to put what I mean into perspective.

12 o' clock is supposed to be the theropod death pose, 6' o clock is the horizontal posture, 4' o clock is the "jack knife" posture. In the horizontal pose, the body would have to arch and contract in unusual directions to the point it almost looks like it's working against gravity. Whereas in the jack knife posture, only the neck would have to undergo any significant bending (which can be explained by water transport. Look up the experiment done with chickens) while the tail and the feet would just have to relax (seen in dead birds) to get the pose.

Of course, in the end this is just my uneducated opinion, so I won't claim to be the final authority on this topic.

@Eye Lad Agreed, but at the same time, it does bear resemblance with modern day birds. Large birds have this cursorial gait and to me, this posture gives off those vibes.

@ScaryLookinHobo They mention that in the top skeletal diagram. "A horizontal posture of trunk and tail may have been appropriate for prey capture but would have unnecessarily increased the rotational inertia during running." But yeah you're right. Aside from basic anatomy, there really isn't much we know about these animals. Initially I thought this would be wrong since upright dinosaurs are accepted as a dated posture. But one of the main arguments for that is the lack of tail drag marks, and the second skeletal still has its tail aloft.

@Friendly Kelbeam of the Hood Yeah that probably sums it up. I think the first two images would be the posture it would assume when standing still or walking slowly, since that would allow it scan its environment for potential prey or enemies. While its running/speedwalking gait would be more horizontal. Basically this would be its alert posture

While this would be its regular gait posture.