{{Short description|Extinct genus of reptiles}} {{distinguish|Bathysuchus|Brachiosuchus}} {{Automatic taxobox | fossil_range = [[Late Triassic]], {{Fossil range|228|209}} | image = Brachysuchus megalodon Holotype UMMNH.jpg | image_upright = 1.15 | image_caption = Skull of ''Brachysuchus megalodon'' in the [[University of Michigan Museum of Natural History]] | taxon = Brachysuchus | authority = Case, 1929 | type_species = {{extinct}}'''''Brachysuchus megalodon''''' | type_species_authority = Case, 1929 }}
'''''Brachysuchus''''' (from [[Ancient Greek]] [[wikt:βραχύς|βραχύς]] (''brakhús''), meaning "short", and [[wikt:Σοῦχος|Σοῦχος]] (''Soûkhos''), meaning "[[Sobek]]") is an [[extinct]] [[genus]] of [[parasuchid]] [[phytosaur]]s known from the late [[Triassic]] [[period (geology)|period]] ([[Carnian]] stage) of [[Dockum Group]] in [[Texas]], United States. It is known from the [[holotype]] [[University of Michigan Museum of Natural History|UMMP]] 10336<ref>{{cite web |title=UMMP VP 10336 |url=https://umorf.ummp.lsa.umich.edu/wp/specimen-data/?Model_ID=1368 |website=University of Michigan Online Repository of Fossils |publisher=University of Michigan Museum of Paleontology |access-date=16 July 2020}}</ref> is composed of a [[skull]], lower [[jaw]]s and partial [[postcranium]] and from the associated paratype UMMP 14366, nearly complete skull, recovered from the 'Pre-Tecovas Horizon' in the [[Dockum Group]].<ref name="Case1929">{{cite journal|author=Case, E. C. |year=1929 |title=Description of the skull of a new form of phytosaur with notes on the characters of described North American phytosaurs |journal=Memoirs of the University of Michigan Museums, Museum of Paleontology |volume=2 |pages=1–56 }}</ref><ref name="Stocker2010">{{cite journal|author=Michelle R. Stocker |year=2010 |title=A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of ''Leptosuchus'' Case, 1922 |journal=Palaeontology |volume=53 |issue=5 |pages=997–1022 |doi=10.1111/j.1475-4983.2010.00983.x |s2cid=83536253 |doi-access=free }}</ref> It was first named by Case in [[1929 in paleontology|1929]] and the [[type species]] is ''Brachysuchus megalodon''. Its closest relative was ''[[Angistorhinus]]''.<ref name="Stocker2010"/> However, its rostral crest was much smaller than that of ''Angistorhinus,'' and the [[Rostrum (anatomy)|rostrum]] as a whole is shorter and thicker.
== Features == The [[Mandible|lower jaws]] of ''Brachysuchus'' are expanded at the tip to form a large bulge, holding the creature's largest [[Tusk|tusks.]] The surface of this part of the [[bone]] has a wrinkled look, with many [[blood vessel]]s running through it. In the lower jaw, there are three tusks in each side of this protuberance. Behind this part the jaws have fused together for a little under half their length before diverging after thirty-one of forty-six post-protuberance [[Tooth|teeth.]] While some of the tusks at the tip are missing, most of the rest of the teeth in the jaw are still present. There are new tusks forming in the [[Dental alveolus|sockets]], indicating that ''Brachysuchus'' [[Polyphyodont|regrew teeth]] all its life. There is a large [[foramen]] between the [[Mandible|dentary]], the [[Angular bone|angular]] and the prearticular that passes right through the jaw (visible on the picture).<ref name=":0">{{Cite web|url=https://scholar.google.com/scholar_lookup?hl=en&publication_year=1930&pages=155-161&author=E.+C.+Case&title=On+the+lower+jaw+of+Brachysuchus+megalodon.|title=Google Scholar|website=scholar.google.com|access-date=2018-05-13}}</ref>
The teeth themselves are [[Asymmetry|asymmetrical]] in [[Cross section (geometry)|cross-section]], with the outer side more [[wikt:convex|convex]] than the inner side. This asymmetry increases from front to back. They are long and conical, and those from the ninth to twenty-ninth have [[Fluting (architecture)|flutings]] on the sides. From the thirtieth to the forty-ninth, they have no flutings but are [[crenulate]]d and broaden antero-posteriorly. This suggests that these teeth were better for slicing [[Predation|prey]] than the previous tusks and conical teeth, which would have impaled and injured it. In parts of the jaws the fused section in the middle rises so high that the teeth could only grip prey and could probably have done little damage.<ref name=":0" />
The prearticular is fused with the [[Articular bone|articular]].<ref name=":0" />
The skull is around 125 cm long, with a distinctive hooked tip. It is much shorter and broader than that of many phytosaurs such as ''[[Leptosuchus]]'' or ''Angistorhinus''. The [[Orbit (anatomy)|eye sockets]] are narrow and long, and the [[Skull|fenestrae]] are smaller and less rounded than ''Angistorhinus.'' It has a comparatively small rostral crest. There are several rough surfaces at the posterior end denoting probable [[Muscle|muscle attachments]], which show that it had very powerful jaw muscles and a strong bite.<ref name=":0" /><ref>{{Cite web|url=http://palaeos.com/vertebrates/archosauria/parasuchia2.html|title=Palaeos Vertebrates: Archosauria: Phytosauridae|website=palaeos.com|access-date=2018-05-13}}</ref>
Overall ''Brachysuchus'' was approximately eight metres long, much bigger than most contemporary phytosaurs. It had extremely heavy jaws and a relatively short fused region, giving it a wider bite. There is also evidence of heavily developed jaw muscles. This, as well as the cutting teeth mentioned earlier, indicates that ''Brachysuchus'' preyed on different animals to its thinner-jawed relatives. Instead of using its jaws to catch [[fish]], it was able to attack and feed off the heavily [[Armour (anatomy)|armoured]] [[stegocephalia]]ns that roamed the surrounding area, and would probably have eaten other phytosaurs if food was scarce. The slightly deformed tip of one specimen's lower jaw suggests that it used a lot of force to break through its prey's armour.<ref name=":0" />
==References== {{Reflist}}
{{Portal|Paleontology}}
{{Phytosauria}} {{Taxonbar|from=Q4953588}}
[[Category:Phytosauria]] [[Category:Prehistoric reptile genera]] [[Category:Carnian genera]] [[Category:Late Triassic reptiles of North America]] [[Category:Triassic geology of Texas]] [[Category:Paleontology in Texas]] [[Category:Fossil taxa described in 1929]] [[Category:Taxa named by Ermine Cowles Case]]