Acrocanthosaurus

*Acrocanthosaurus* immediately‭ ‬sticks out from other large theropods with its high dorsal spines than run from the neck to the tip of the tail.‭ ‬There have been many artistic representations for this structure from the spines standing proud from the body,‭ ‬to supporting a flap of skin.‭ ‬Modern thinking however comes from the examination of the lower spines that have attachments for muscles.‭ ‬This has led to the suggestion that the spines supported a hump of tissue that ran down the length of *Acrocanthosaurus*.
       The purpose of the hump of *Acrocanthosaurus* has been subject to a lot of speculation.‭ ‬Some have said that it would provide a larger surface area than *Acrocanthosaurus* would have had without it,‭ ‬helping with temperature exchange and reducing negative effects of gigantothermy.‭ ‬It could have been composed of fatty tissue and used to keep *Acrocanthosaurus* going for extended periods without eating.‭ ‬It may have also been a form of visual display for other *Acrocanthosaurs* to gauge its level of health,‭ ‬perhaps even having a different colour or markings to the rest of its body.
       It is possible that the hump served double duty.‭ ‬If composed of fatty tissue,‭ *‬Acrocanthosaurus* would have had to eat more than the minimum it would have had to just to survive.‭ ‬This would then result in a large and well maintained hump that would speak along the lines of‭ '‬Look at‭ ‬my hump.‭ ‬That is how much of a successful predator I am.‭ ‬That‭’‬s why I am more worthy of passing my genes down to the next generation‭'‬.‭ ‬It could have also worked in dominance displays between two *Acrocanthosaurus*,‭ ‬with the larger hump meaning that they were a more capable hunter‭ ‬and knew what to do when things came to a fight.‭ ‬The *Acrocanthosaurus* with the smaller hump would then probably back down instead of go up against what appeared to be a stronger and more capable *Acrocanthosaurus*.
*Acrocanthosaurus* was big for its time,‭ ‬a family trait that is shared with‭ ‬some other carcharodontosaurids such as *Carcharodontosaurus* and *Giganotosaurus*.‭ ‬At‭ ‬eleven and a half‭ ‬meters,‭ *‬Acrocanthosaurus* would have been the largest predator of its time and locale.‭ ‬Its diet as a result probably consisted of hadrosaurs and smaller sauropods,‭ ‬dinosaurs that were large enough to provide sufficient sustenance,‭ ‬while being too slow to escape.‭ ‬Study of the area that the main *Acrocanthosaurus* remains come from suggest that it was probably the apex predator of its location,‭ ‬with most other predators such as *Deinonychus* being much smaller.
       The skull of *Acrocanthosaurus* featured large fenestra,‭ ‬a necessary adaptation to reduce the weight of its huge skull that could approach up to a‭ ‬one hundred and thirty‭ centi‬meters long.‭ ‬The teeth of *Acrocanthosaurus* were curved and serrated like other members of the carcharodontosaurid group.‭ ‬The maxilla and premaxilla contained‭ ‬a total of around thirty-eight teeth.‭ ‬The teeth in the lower jaw are generally smaller than those above and can approach up to thirty in number.‭ ‬Another carcharodontosaurid trait is the bony brow ridge above the eye,‭ ‬formed by the lacrimal and postorbital bones coming together.
       Computer reconstruction of the inner ear has shown that the‭ '‬resting position‭' ‬of the head of *Acrocanthosaurus* was twenty-five degrees below zero horizontal.‭ ‬This may give the impression that *Acrocanthosaurus* usually walked around looking slightly towards the ground.
       Reconstruction of an *Acrocanthosaurus* forelimb suggests that there would have been large amounts of cartilage between the bones.‭ ‬This comes from the fact that bones themselves do not make perfect joints and would need the extra cartilage in order to articulate properly.‭ ‬The arms of *Acrocanthosaurus* did not have a huge range of motions.‭ ‬The arm could not fully extend and could only manage limited flexing.‭ ‬The humerus could retract back quite away,‭ ‬as if *Acrocanthosaurus* was pulling something towards its chest.‭ ‬As is commonly seen in larger theropods,‭ ‬the fore arm could not twist like a human arm can.‭ ‬When at rest the arms would have faced medially inwards,‭ ‬like when you clap your hands together.‭ *‬Acrocanthosaurus* had three digits on the end of its arms with the first and second claws probably being permanently flexed.‭ ‬The third and smallest claw may have been able to retract as well.
       Altogether,‭ *‬Acrocanthosauru*s may have grabbed large prey such as sauropods like *Paluxysaurus* with its jaws and then latched onto it with its claws. ‭The neck vertebrae also interlocked together for greater rigidity which means that *Acrocanthosaurus* could hold onto large prey with its jaws without sustaining injury to the neck. ‬Lighter prey such as ornithopod dinosaurs like *Tenontosaurus* may have been pulled towards *Acrocanthosaurus* while it continued to work with its jaws,‭ ‬whereas it would probably have to pull itself onto heavier prey.‭ ‬Alternatively it may have held its prey with its jaws while repeatedly slashing at it with its claws,‭ ‬the more the prey struggled,‭ ‬the worse its wounds became.