Allognathosuchus
Allognathosuchus (meaning "other jaw crocodile") is an extinct genus of alligatorine crocodylian with a complicated taxonomic history. It was named in 1921. Description. "Allognathosuchus" was a medium-sized predator up to 1.5 m in length. 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. Taxonomy. The type species, "A. polyodon", is from the Eocene -age Bridger Formation of Wyoming; it is based on fossils that are difficult to distinguish from other Paleogene alligatorids. "A. heterodon" is from the Eocene-age Wasatch Formation of Wyoming, "A. wartheni" is from the Eocene-age Wildwood Formation (also known as the "Wildwood alligatorid" and possibly two species), and "A. woutersi", which may belong to "Diplocynodon", instead, is from the Early Eocene of Belgium. "A. polyodon", "A. heterodon", and "A. wartheni" span the Clarkforkian, Wasatchian, and Bridgerian North American Land Mammal Ages. Several other genera and species were previously assigned to "Allognathosuchus", giving it a potential Upper Cretaceous-Oligocene  stratigraphic 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. 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. Cladogram  from 2018 Bona "et al." study: Cladogram from 2019 Massonne "et al." study: Cladogram from 2020 Cossette & Brochu study: