The water mites of Western Australia (Acari: Hydrachnidia), with the description of 13 new species Author Orginal, Harry Smit text Acarologia 2021 2021-10-27 61 4 928 966 journal article 2107-7207 Oxus ( Oxus ) troma Cook, 1986 ( Figures 8 A-C) New records — 1/0, spring along Mt Barker – Denham Road, 34°45.528′ S 117°29.607′ E, 75 m asl, 5 Feb. 2019 ; 1/1/0, Rowell’s Pool, Mount Frankland South NP, 34°49.120′ S 116°35.657′ E , 34 m asl, 6 Feb. 2019 ; 4/0, Styx River at crossing with Fernley Road, Denham, 34°53.056′ S 117°06.266′ E , 43 m asl, 6 Feb. 2019 ; 4/0, Glenoran Pool, W of Glenoran, 34°12.979′ S 115°56.436′ E , 160 m asl, 8 Feb. 2019 ; 1/0, small tributary of Big Brook, Pemberton, 34°23.718′ S 115°59.614′ E , 120 m asl, 10 Feb. 2019 ; 1/0, Beedelup Brook, downstream of falls, Beedelup NP, 34°25.107′ S 115°52.071′ E , 103 m asl, 10 Feb. 2019 . Remarks — According to Cook (1986) O. troma has a narrow median sclerite in the dorsal strip. This strip is absent in the specimens from Western Australia ( Figure 8A ). As the specimens of this study agree in all other characters, I have assigned them O to. troma . More research is needed to elucidate the importance of presence or absence of the dorsal sclerite. Distribution — The species has been reported previously from Tasmania , New South Wales and Queensland , and is reported here for the first time from Western Australia .