It was phylogenetically defined in 2004 as the most recent common ancestor of Peirosaurus and Lomasuchinae and all of its descendants.

[1] Lomasuchinae was defined in the same 2004 study as the most recent common ancestor of Lomasuchus and Mahajangasuchini and all of its descendants.

Mahajangasuchini, also constructed in the study, was defined as the most recent common ancestor of Mahajangasuchus and Uberabasuchus and all of its descendants.

[1] However, all more recent phylogenetic analyses placed Mahajangasuchus within its own family, Mahajangasuchidae, along with the newly named Kaprosuchus.

Montealtosuchus arrudacamposi, a new peirosaurid crocodile (Mesoeucrocodylia) from the Late Cretaceous Adamantina Formation of Brazil.