Allognathosuchus was a medium-sized predator up to 1.5 m in length.[3] This alligatorine is known for its stout jaws and bulbous teeth, found near the rear of the tooth row in upper and lower jaws. These adaptations have historically been interpreted as having been for crushing mollusks. Isolated bulbous teeth are often assigned to this genus, although such teeth are known from other crocodyliform lineages.
Several other genera and species were previously assigned to Allognathosuchus, giving it a potential Upper Cretaceous-Oligocenestratigraphic range, and a geographic range covering North America, Europe, and Africa. Christopher Brochu reviewed the genus in 2004, and in light of the fragmentary remains of several of the species involved, recommended conservative use of the genus. He excluded Albertochampsa langstoni, Arambourgia gaudryi, and Wannaganosuchus brachymanus from Allognathosuchus, and resurrected Hassiacosuchus and Navajosuchus from synonymy with Allognathosuchus after finding them not to group with A. polyodon to the exclusion of other alligatorines.[4]
Recent studies have consistently resolved Allognathosuchus polyodon and Allognathosuchus wartheni as members of Alligatorinae, although their relative placement is disputed, as shown by the cladograms below.[5][6][7]
