Enigmatic crocodilian taxa

Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They represented the dominant group of crocodilians in the region during most of the Cenozoic, first appearing in the fossil record in the Eocene of Australia, and surviving until the arrival of humans: the Late Pleistocene on the Australian continent and during the Holocene in the Pacific islands of Fiji, New Caledonia and Vanuatu.

Tomistominae 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.

Brevirostres is an obsolete group of crocodilians that, as originally formulated, included alligatoroids and crocodyloids, but not gavialoids. Results of molecular phylogenetic analysis uniformly draw gavialoids and crocodyloids into a close relationship; in that case, Brevirostres becomes obsolete with Crocodilia.