There is a single smooth, yellow callus ridge 4–6 mm (0.16–0.24 in) long, along the mid-line of the labellum.

[2][3][4] Diuris tinkeri was first formally described in 2013 by David Jones and Christopher J. French in Australian Orchid Review, from a specimen collected in the Western Flora Caravan Park near Eneabba in 1997.

[5] The specific epithet (tinkeri) honours Allan Tinker, who recognised the distinctiveness of the species.

[4] Arrowsmith donkey orchid grows in woodland, shrubland and kwongan in near-coastal areas, from near Geraldton to near Yanchep in the Geraldton Sandplains, Jarrah Forest and Swan Coastal Plain bioregions of south-western Western Australia.

[2][3][4] Diuris tinkeri is listed as "not threatened" by the Western Australian Government Department of Biodiversity, Conservation and Attractions.