Microsynodontis nasutus is a species of upside-down catfish endemic to Gabon where it occurs in the Ogowe River. It was first described in 2004 by Ng Heok Hee.

The genus Microsynodontis is restricted to the rivers of western Africa (from the Saint Paul River drainage south and east to the Congo River drainage), and comprises small mochokid catfishes diagnosed by the following synapomorphies: a narrow mesethmoid, lack of free orbital margin, transverse ventral fold of branchiostegal membranes, slender cleithral process, and a rounded or truncate caudal fin (Howes, 1980).

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