Adamystis persiangulfensissp. nov. is described based on female, male, tritonymph, deutonymph and larva stages collected in the littoral zone of mangrove forests in Qeshm Island, in the eastern part of the Persian Gulf, southern Iran. This new species is distinguished by having two pairs of adoral setae; chelicera with one seta; palpal tarsus with 14 setae; idiosoma with one poorly defined (weakly sclerotized) shield; dorsum laterally at least with 19 pairs of lens-like structures and five pairs of aggenital setae (ag_1–5). Additionally, an identification key to known species of Adamystis is updated.