The hoplomachus was outfitted in virtually the same way as the Thraex, except that the crest of his helmet lacked the griffin protome (the head of an animal or human used as a decorative element). The principal weapons of the hoplomachus were a lance (hasta) and a short sword or dagger that was held in the left hand, together with a small round shield. This bronze shield is reminiscent of the one used by the Greek hoplite, as is the lance, which may explain why the hoplomachus and the Thraex were matched against the murmillo, who carried the sword and shield of the Roman legionary.
In this scene from the Zliten mosaic, one can discern the tall greaves and leggings and rectangular shield of the Thraex, as well as the feathers that decorate his helmet. The murmillo, the crest of his helmet equally elaborate, thrusts his sword over the smaller curved shield of his opponent. The other scene depicts a hoplomachus, who can be identified by his lance, small round shield, and dagger. He stands aside, awaiting the verdict, as the murmillo, who has laid down his shield and is bleeding, raises his finger (ad digitum) in admission of defeat to the referee.
References: The illustration is from Gladiators at Pompeii (2003) by Luciana Jacobelli.