EusuchiaEusuchia is a clade of neosuchian crocodylomorphs that first appeared in the Early Cretaceous, which includes modern crocodilians. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-T extinction. Eusuchia was originally defined by Thomas Henry Huxley in 1875 as an apomorphy-based group, meaning that it was defined by shared characteristics rather than relations. These characteristics include pterygoid-bounded choanae and vertebrae which are procoelous (concave from the front and convex from the back).
AlligatoroideaAlligatoroidea is one of three superfamilies of crocodylians, the other two being Crocodyloidea and Gavialoidea. Alligatoroidea evolved in the Late Cretaceous period, and consists of the alligators and caimans, as well as extinct members more closely related to the alligators than the two other groups. The superfamily Alligatoroidea is thought to have split from the crocodile-gharial lineage in the late Cretaceous, about 80 million years ago, but possibly as early as 100 million years ago based on molecular phylogenetics.
GryposuchusGryposuchus is an extinct genus of gavialid crocodilian. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the Miocene epoch (Colhuehuapian to Huayquerian). One recently described species, G. croizati, grew to an estimated length of . Gryposuchus is the type genus of the subfamily Gryposuchinae, although a 2018 study indicates that Gryposuchinae and Gryposuchus might be paraphyletic and rather an evolutionary grade towards the gharial.
IkanogavialisIkanogavialis is an extinct genus of gavialid crocodilian. Fossils have been found in the Urumaco Formation in Urumaco, Venezuela and the Solimões Formation of Brazil. The strata from which remains are found are late Miocene in age, rather than Pliocene as was once thought. A possible member of this genus survived into the Late Holocene on Muyua or Woodlark Island in Papua New Guinea. Ikanogavialis had a dorsoventrally deep snout and a distinctive notch between the dentary and maxillary alveoli.
ThoracosaurusThoracosaurus is an extinct genus of long-snouted eusuchian which existed during the Late Cretaceous and Early Paleocene in North America and Europe. Thoracosaurus had traditionally been thought to be related to the modern false gharial, largely because the nasal bones contact the premaxillae. Phylogenetic work starting in the 1990s instead supported affinities within Gavialoidea exclusive of such forms, although a 2018 tip dating study simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data suggests that it might have been a non-crocodylian eusuchian.
CrocodyloideaCrocodyloidea is one of three superfamilies of crocodilians, the other two being Alligatoroidea and Gavialoidea, and it includes the crocodiles. Crocodyloidea may also include the extinct Mekosuchinae, native to Australasia from the Eocene to the Holocene, although this is disputed. Cladistically, it is defined as Crocodylus niloticus (the Nile crocodile) and all crocodylians more closely related to C. niloticus than to either Alligator mississippiensis (the American alligator) or Gavialis gangeticus (the gharial).
TomistominaeTomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a freshwater species that lives only in southeast Asia, extinct tomistomines had a global distribution and lived in estuaries and along coastlines. The classification of tomistomines among Crocodylia has been in flux; while traditionally thought to be within Crocodyloidea, molecular evidence indicates that they are more closely related to true gharials as members of Gavialoidea.
TomistomaTomistoma is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. Tomistoma contains one extant (living) member, the false gharial (Tomistoma schlegelii), as well as potentially several extinct species: T. cairense, T. lusitanicum T. coppensi, and T. dowsoni. However, these species may need to be reclassified to different genera as studies have shown them to be paraphyletic, for example: previously assigned species T.
Tomistoma cairenseTomistoma cairense is an extinct species of gavialoid crocodilian from the Lutetian stage of the Eocene era. It lived in North East Africa, especially Egypt. Remains of T. cairense have been found in the Mokattam Formation, in Mokattam, Egypt. Tomistoma cairense did not have a Maxilla process within their lacrimal gland, whereas all extant (living) crocodilians do.
EosuchusEosuchus ("dawn crocodile") is an extinct genus of eusuchian crocodylomorph, traditionally regarded as a gavialoid crocodilian. It might have been among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier putative members such as Thoracosaurus and Eothoracosaurus. Fossils have been found from France as well as eastern North America in Maryland, Virginia, and New Jersey. The strata from which specimens have been found date back to the late Paleocene and early Eocene epochs.