Editing Allosaurus (section)

===Skull===
[[File:Allosaurus jimmadseni skull and diagram.png|thumb|''A. jimmadseni'' skull with diagram highlighting individual bones]]
The skull and teeth of ''Allosaurus'' were modestly proportioned for a theropod of its size. Paleontologist [[Gregory S. Paul]] gives a length of {{cvt|845|mm}} for a skull belonging to an individual he estimates at {{cvt|7.9|m}} long.<ref name=GSP88>{{cite book |last=Paul |first=Gregory S. |title=Predatory Dinosaurs of the World |year=1988 |publisher=Simon & Schuster |location=New York |isbn=978-0-671-61946-6 |chapter=Genus ''Allosaurus'' |pages=[https://archive.org/details/predatorydinosau00paul/page/307 307–313] |chapter-url=https://archive.org/details/predatorydinosau00paul/page/307 }}</ref> Each [[premaxilla]] (the bones that formed the tip of the snout) held five teeth with D-shaped cross-sections, and each [[maxilla]] (the main tooth-bearing bones in the upper jaw) had between 14 and 17 teeth; the number of teeth does not exactly correspond to the size of the bone. Each [[dentary]] (the tooth-bearing bone of the lower jaw) had between 14 and 17 teeth, with an average count of 16. The teeth became shorter, narrower, and more curved toward the back of the skull. All of the teeth had saw-like edges. They were shed easily, and were replaced continually, making them common fossils.<ref name=JM76/> Its skull was light, robust and equipped with dozens of sharp, [[serrated]] teeth.

The skull had a pair of [[Horn (anatomy)|horn]]s above and in front of the eyes. These horns were composed of extensions of the [[lacrimal bone]]s,<ref name=JM76/> and varied in shape and size. There were also lower paired ridges running along the top edges of the [[nasal bone]]s that led into the horns.<ref name=JM76/> The horns were probably covered in a [[keratin]] sheath and may have had a variety of functions, including acting as sunshades for the eyes,<ref name=JM76/> being used for display, and being used in combat against other members of the same species<ref name=GSP88/><ref name=REM77>{{cite journal |last=Molnar |first=Ralph E. |author-link=Ralph Molnar |year=1977 |title=Analogies in the evolution of combat and display structures in ornithopods and ungulates |journal=Evolutionary Theory |volume=3 |pages=165–190}}</ref> (although they were fragile).<ref name=JM76/> There was a ridge along the back of the skull roof for muscle attachment, as is also seen in [[Tyrannosauridae|tyrannosaurid]]s.<ref name=GSP88/>

Inside the lacrimal bones were depressions that may have held [[gland]]s, such as [[salt gland]]s.<ref name=DBN85>{{cite book |last=Norman |first=David B. |author-link=David B. Norman |title=The Illustrated Encyclopedia of Dinosaurs: An Original and Compelling Insight into Life in the Dinosaur Kingdom |chapter=Carnosaurs |year=1985 |publisher=Crescent Books |location=New York |pages=62–67 |isbn=978-0-517-46890-6 }}</ref> Within the maxillae were [[Maxillary sinus|sinus]]es that were better developed than those of more [[Basal (phylogenetics)|basal]] theropods such as ''[[Ceratosaurus]]'' and ''[[Marshosaurus]]''; they may have been related to the [[sense of smell]], perhaps holding something like [[Vomeronasal organ|Jacobson's organ]]s. The roof of the braincase was thin, perhaps to improve [[thermoregulation]] for the brain.<ref name=JM76/> The skull and lower jaws had joints that permitted motion within these units. In the lower jaws, the bones of the front and back halves loosely articulated, permitting the jaws to bow outward and increasing the animal's gape.<ref name="GSP88e">[[Gregory S. Paul|Paul, Gregory S.]] (1988). ''Predatory Dinosaurs of the World''. 91 and Figure 4–5 (93).</ref> The [[braincase]] and [[Frontal bone|frontal]]s may also have had a joint.<ref name=JM76/>