While the above definition is fine, it is illustrated with a modern coin. These ancients have cuds: The cud under the turtle is not really a killer whale. This is a reverse die clash so severe it broke out a chunk of the die at the upper right.
TRAJAN, SESTERTIUS, RIC Vol. II, Rome, No. 534, 98-117AD, Struck c103-111AD Obverse depiction: Trajan, head facing right, wearing aegis Inscription: IMP CAES NERVAE TRIANO AVG GER DAC PM TRP COS V PP Reverse depiction: Trajan galloping on horseback spearing a fallen Dacian soldier Inscription: SPQR OPTIMO PRINCIPI - in exergue S C TRAJAN AE orichalcum sestertius. Struck 103-111 AD. IMP CAES NERVAE TRAIANO AVG GER DAC P M TR P COS V P P, laureate bust right. Reverse - S P Q R OPTIMO PRINCIPI, Fortuna standing left, holding rudder resting on prow and cornucopia. RIC 500. Trajan AE AS Rome Mint 99-100 AD Obverse: IMP CAES NERVA TRAIAN AVG GERM P M Head of Trajan, laureate, right Reverse: TR POT COS III P P S C Victory, draped, advancing left, holding shield inscribed SPQR in right hand and palm in left References: RIC II 417 (10.4g 27mm) Trajan. 98-117 AD. AR Denarius ,Struck 112-116 AD. IMP TRAIANO AVG GER DAC P M TR P COS VI P P, laureate and draped bust right / S P Q R OPTI-MO PRINCIPI, Trajan's column. RIC II 292; BMCRE 452; RSC 558 IMP TRAIANO AVG GER DAC PM TRP, laureate head right, slight drapery on left shoulder. COS V PP SQPR OPTIMO PRINC legend with Victory standing right, foot on rock, inscribing DA-CI-CA on a shield set on a palm stump. Celebrating the victory over Dacia Trajan denarius , Rome mint c108-109AD , Dacian seated on pile of arms, in attitude of mourning, foot on helmet; one round and one oblong shield; on l., two curved swords; on r., two spears. DAC CAP below for DACIAN CAPTIVE. (DAC CAP below for DACIAN CAPTIVE , RIC II 98).
Sestertius of Trajan 104/5 -107AD, Obv bust right laureate aegis on far shoulder. Rv. Victory standing right placing shield inscribed with VIC/ DAC on palm tree. RIC 528 Woytek 204cA. 28.90 grms 35mm Photo by W. Hansen. The conquest of Dacia is a centerpiece of Trajanic propaganda on his coinage especially during the period between 102 to 111 AD. There is an extraordinary wealth of different types some copied from previous emperors, others completely new. Pioneering work by scholars such as Hill and Woytek are now allowing us to be able to examine how this coinage would be seen by the target audience and how all these issues worked together to form a more complete picture