The mandible lacks palpi; the incisor has four cusps and a spine-row of three or four spines; the molar is stout and distally truncated.

[4] U. sheltoni closely resembles Munna lundae from southern Chile, but differs in having a relatively broader pereon and pleotelson.

The colour pattern, especially the distinctive cruciform pigmentation of the pleotelson, makes this species easily recognisable.

[2] U. sheltoni is found in estuaries in South Africa and is part of a diverse epifauna associated with the macroalgae, including several dipterans, gastropods, isopods, and amphipods.

[5] U. sheltoni has been recorded at: Sandvlei Estuary, False Bay, Western Cape, on ruppia weed in water of 9‰ salinity; Kosi Lake complex (Kwa-Zulu Natal), on Potamogeton weed; and Lake Sibhayi (KwaZulu-Natal) on submerged vegetation.