Allodaposuchus is one of the earliest members of the Crocodylia clade, the most exclusive group including all modern crocodylians.
The ancestors of Allodaposuchus and other crocodylians were part of a larger evolutionary group called Eusuchia that originated in the Early Cretaceous.
Allodaposuchus is part of an evolutionary radiation of eusuchians that happened later in the Cretaceous as they spread to multiple continents.

When Franz Nopcsa named Allodaposuchus, he proposed that it was a close relative of Leidyosuchus, a crocodylian from Canada.
However, Nopsca could only base this assignment on a few fragments of bone.
After more complete material was uncovered from Spain and France, Allodaposuchus was reinterpreted as a non-crocodylian eusuchian in 2001.
The 2001 study recognized a close relationship between Allodaposuchus and Hylaeochampsa, a eusuchian from the Early Cretaceous of England.
A 2010 phylogenetic analysis supported a relationship similar to Nopsca's by placing Allodaposuchus within Alligatoroidea, a group of crocodylians that includes modern-day alligators and Leidyosuchus.
The most recent phylogenetic analyses of Allodaposuchus – published alongside the descriptions of A. palustris in 2014 and A. hulki in 2015 – place it within Crocodylia but outside Alligatoroidea as a sister taxon (closest relative) of the clade Brevirostres, which includes Alligatoroidea and Crocodyloidea, the group including crocodiles and their closest extinct relatives.
According to these studies Allodaposuchus is more closely related to Alligatoroidea and Crocodyloidea than it is to the third major group of living crocodylians, Gavialoidea, which includes modern gharials.
Among extinct groups, Allodaposuchus is most closely related to the genus Borealosuchus, which existed in North America from the Late Cretaceous to the Eocene, and the family Planocraniidae, which existed in North America, Europe, and Asia from the Paleocene to the Eocene.

The 2015 analysis also indicated a close relationship between Allodaposuchus species and a genus called Arenysuchus, regarded as a crocodyloid in earlier analyses.
Like Al.
palustris and Al.
hulki, Arenysuchus comes from the Tremp Formation of Spain, although from a different locality called Elías.
Arenysuchus fell within the Allodaposuchus clade, being more closely related to A. hulki and A. precedens than is A. palustris, raising the possibility that Allodaposuchus is a polyphyletic taxon (i.e., not a true clade) .
The authors of the analysis proposed the name Allodaposuchia for the clade containing Arenysuchus and Allodaposuchus species.
Below is a cladogram from that analysis:
Allodaposuchus is one of the earliest members of the Crocodylia clade, the most exclusive group including all modern crocodylians. The ancestors of Allodaposuchus and other crocodylians were part of a larger evolutionary group called Eusuchia that originated in the Early Cretaceous. Allodaposuchus is part of an evolutionary radiation of eusuchians that happened later in the Cretaceous as they spread to multiple continents.
When Franz Nopcsa named Allodaposuchus, he proposed that it was a close relative of Leidyosuchus, a crocodylian from Canada. However, Nopsca could only base this assignment on a few fragments of bone. After more complete material was uncovered from Spain and France, Allodaposuchus was reinterpreted as a non-crocodylian eusuchian in 2001. The 2001 study recognized a close relationship between Allodaposuchus and Hylaeochampsa, a eusuchian from the Early Cretaceous of England. A 2010 phylogenetic analysis supported a relationship similar to Nopsca's by placing Allodaposuchus within Alligatoroidea, a group of crocodylians that includes modern-day alligators and Leidyosuchus. The most recent phylogenetic analyses of Allodaposuchus – published alongside the descriptions of A. palustris in 2014 and A. hulki in 2015 – place it within Crocodylia but outside Alligatoroidea as a sister taxon (closest relative) of the clade Brevirostres, which includes Alligatoroidea and Crocodyloidea, the group including crocodiles and their closest extinct relatives. According to these studies Allodaposuchus is more closely related to Alligatoroidea and Crocodyloidea than it is to the third major group of living crocodylians, Gavialoidea, which includes modern gharials. Among extinct groups, Allodaposuchus is most closely related to the genus Borealosuchus, which existed in North America from the Late Cretaceous to the Eocene, and the family Planocraniidae, which existed in North America, Europe, and Asia from the Paleocene to the Eocene.
The 2015 analysis also indicated a close relationship between Allodaposuchus species and a genus called Arenysuchus, regarded as a crocodyloid in earlier analyses. Like Al. palustris and Al. hulki, Arenysuchus comes from the Tremp Formation of Spain, although from a different locality called Elías. Arenysuchus fell within the Allodaposuchus clade, being more closely related to A. hulki and A. precedens than is A. palustris, raising the possibility that Allodaposuchus is a polyphyletic taxon (i.e., not a true clade) . The authors of the analysis proposed the name Allodaposuchia for the clade containing Arenysuchus and Allodaposuchus species. Below is a cladogram from that analysis:
Allodaposuchus