Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea

Alligatoroidea

Alligatoroidea is a superfamily of crocodilians that evolved in the Late Cretaceous period. Cladistically, it is defined as Alligator mississippiensis and all crocodylians more closely related to A. mississippiensis than to either Crocodylus niloticus or Gavialis gangeticus ....

 and Crocodyloidea

Crocodyloidea

Crocodyloidea is a superfamily of crocodilians that evolved in the Late Cretaceous period. Cladistically, it is defined as Crocodylus niloticus and all crocodylians more closely related to C. niloticus than to either Alligator mississippiensis or Gavialis gangeticus .- Phylogeny :Cladogram after...

. Although many extinct species are known, only the gharial

Gharial

The gharial , , also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts...

 Gavialis gangeticus and possibly the False gharial

False gharial

The false gharial , also known as the Malayan gharial, false gavial, or Tomistoma is a freshwater crocodile of the Crocodylidae family with a very thin and elongated snout...

 Tomistoma schlegelii are alive today.

Classification

Gavialoidea contains the family Gavialidae

Gavialidae

Gavialidae is a family of reptiles within the order Crocodilia. Gavialidae consists of only one surviving species, the gharial , which is native to India. Many extinct species are also known...

 and several more basal

Basal (phylogenetics)

In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 extinct forms such as Thoracosaurus

Thoracosaurus

Thoracosaurus is an extinct genus of gavialoid crocodilian which existed during the Late Cretaceous and early Paleocene. It contains the species Thoracosaurus neocesariensis in North America and Thoracosaurus macrorhynchus in Europe. A number of species have been referred to this genus, but most...

and Eosuchus

Eosuchus

Eosuchus is an extinct genus of gavialoid crocodilian. It is among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier members such as Thoracosaurus and Eothoracosaurus. Fossils have been found from France as well as eastern North...

. Within Gavialidae are two subfamilies: Gavialidae

Gavialidae

Gavialidae is a family of reptiles within the order Crocodilia. Gavialidae consists of only one surviving species, the gharial , which is native to India. Many extinct species are also known...

, which includes the living gharial, and Gryposuchinae

Gryposuchinae

Gryposuchinae is an extinct subfamily of gavialid crocodylians. Gryposuchines lived mainly in South America during the Oligocene and Miocene epochs. Most were long-snouted coastal forms. The group was named in 2007 and includes genera such as Gryposuchus and Aktiogavialis.-Description:Gryposuchines...

, which includes several extinct forms such as Gryposuchus

Gryposuchus

Gryposuchus is an extinct genus of gavialoid crocodilian. It is the type genus of the subfamily Gryposuchinae. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the early and middle Miocene epoch. One recently described species, G...

and Aktiogavialis

Aktiogavialis

Aktiogavialis is an extinct genus of crocodylian from the Oligocene Epoch some thirty million years ago. Only one species in the genus, Aktiogavialis puertoricensis, has been described so far....

.

In addition to these groups, recent molecular studies suggest that the False gharial and other forms belonging to the crocodylian subfamily Tomistominae

Tomistominae

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...

 may belong to Gavialoidea. As its name suggests, the False gharial is traditionally thought to be only distantly related to the gharial despite its similar appearance. The False gharial and other tomistomines are traditionally classified within the superfamily Crocodyloidea

Crocodyloidea

Crocodyloidea is a superfamily of crocodilians that evolved in the Late Cretaceous period. Cladistically, it is defined as Crocodylus niloticus and all crocodylians more closely related to C. niloticus than to either Alligator mississippiensis or Gavialis gangeticus .- Phylogeny :Cladogram after...

 as close relatives of crocodile

Crocodile

A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

s. This classification is upheld by morphological evidence, which, when incorporated into phylogenetic analyses, often place the group within Crocodyloidea.

Below is a cladogram from Vélez-Juarbe et al. (2007) showing the phylogenetic relationships of members of Gavialoidea, excluding tomistomines.