The author recognised an affinity with other genera allied to the family Rhytidosteidae that had been uncovered in Africa, and proposed their arrangement to a new superfamily Rhytidosteoidea.

[2] The genus has been variously placed in subsequent arrangements, at one time as a familia Derwentiidae that separated the Australian taxa from Indobrachyops found on the Indian subcontinent.

A revision of the Rhytidosteidae (Stereospondyli: Trematosauria) published in 2011 applied phylogenetic methodologies to reassess the relationships of the genera and submerged the Derwentiidae as a new subfamily of Rhytidosteidae that included the genus Indobrachyops as an eastern Gondwanan grouping of Australian and Indian rhytidosteids.

[3] A stereospondyl genus unearthed at sites located in Western Australia and Tasmania in shale deposits dated from the upper Permian to lower Triassic.

[2] Deltasaurus are distinguished from other Australia species of Rhytidosteidae by the straight side of the skull, rather than parabolic outline of Rewana quadricuneata, Arcadia myriadens and Derwentia warreni.