[1] This classification was based on morphological studies primarily focused on analyzing skeletal traits of living and extinct fossil species, and placed the gharials outside the group due to their unique skull structure,[2] and can be shown in the simplified cladogram below:[3] Gavialoidea Alligatoroidea Crocodyloidea However, recent molecular studies using DNA sequencing have rejected Brevirostres upon finding the crocodiles and gavialids to be more closely related than the alligators.

[4][5][6][7][8] The new clade Longirostres was defined by Harshman et al. in 2003,[4] and can be shown in the cladogram below: Alligatoroidea Gavialoidea Crocodyloidea Brevirostres was first named by Karl Alfred von Zittel in 1890.

Tomistoma, as its name implies, is traditionally not considered closely related to Gavialis, but instead classified as a crocodylid.

Recent molecular analyses support von Zittel's classification in placing Tomistoma as a close relative of Gavialis.

If this classification is accepted, Brevirostres can be considered redundant with Crocodylia, as the two names would refer the same clade.