Antoninus Pius, AE Sestertius, struck AD 139. 34 mm, 27.21 g. 

ANTONINVS AVG PIVS PP, laureate head right. 
MAVRETANIA, Mauretania, bare-headed and in military dress, standing left, holding crown and inverted spear. S-C across fields, COS II below.

RIC III 583; BMCRE 1190; Cohen 551.
Very rare. 

With permission of Fritz Rudolf Künker GmbH auction 124, Lot 9145, March 2007.