Dorsetensia is a narrowly coiled discoidal ammonite from the early Middle Jurassic, lower Bajocian,[1] belonging to the family Sonniniidae of the superfamily Hildoceratoidea.

The umbilicus, the opening in the middle of the shell exposing inner whorls, is of moderate size with a sharp, sometimes undercut edge.

The prevailing consensus is these are three distinct genera with Dorsetensia and Witchellia distinguished by shell morphology and stratigraphic disjunction.

Witchellia is from the middle Lower Bajocian Laeviuscula subzone, Sowebvyi Zone and has a distinct tabulate venter even in smooth involute forms.

Dorsetensia is from the middle Bajocian Humphriesianum Zone and has a narrow fastigate (pitched roof) venter.