 The skull of Acrocanthosaurus , like most other allosauroids , was long , low and narrow . The weight @-@ reducing opening in front of the eye socket ( antorbital fenestra ) was quite large , more than a quarter of the length of the skull and two @-@ thirds of its height . The outside surface of the maxilla ( upper jaw bone ) and the upper surface of the nasal bone on the roof of the snout were not nearly as rough @-@ textured as those of Giganotosaurus or Carcharodontosaurus . Long , low ridges arose from the nasal bones , running along each side of the snout from the nostril back to the eye , where they continued onto the lacrimal bones . This is a characteristic feature of all allosauroids . Unlike Allosaurus , there was no prominent crest on the lacrimal bone in front of the eye . The lacrimal and postorbital bones met to form a thick brow over the eye , as seen in carcharodontosaurids and the unrelated abelisaurids . Nineteen curved , serrated teeth lined each side of the upper jaw , but a tooth count for the lower jaw has not been published . Acrocanthosaurus teeth were wider than those of Carcharodontosaurus and did not have the wrinkled texture that characterized the carcharodontosaurids . The dentary ( tooth @-@ bearing lower jaw bone ) was squared off at the front edge , as in Giganotosaurus , and shallow , while the rest of the jaw behind it became very deep . Acrocanthosaurus and Giganotosaurus shared a thick horizontal ridge on the outside surface of the surangular bone of the lower jaw , underneath the articulation with the skull . 
