Types of Gladiators: There were many categories of gladiators, who were distinguished by the kind of armor they wore, the weapons they used, and their style of fighting. Most gladiators stayed in one category, and matches usually involved two different categories of gladiator. The following examples will illustrate some of the different types of gladiators which modern scholars have identified:

• Thracian: Wide-brimmed crested helmet with visor, high greaves on both legs, arm protector, very small shield, and short, curved sword (similar to Spartacus); the victorious gladiator in this mosaic is a Thracian.
• Secutor: Egg-shaped helmet with round eye-holes, greave on one leg, arm protector, legionary-style shield and sword (scutum andgladius); see the small black helmet in the above image and the victorious gladiator in this mosaic. The secutor was called a “chaser,” probably because he was frequently paired with the retiarius, who used running as one of his tactics.
• Retiarius (“net-and-trident” fighter): Arm protector (often topped with a high metal shoulder protector), large net, trident, small dagger, no helmet; the retiarius was the only type of gladiator whose head and face were uncovered. Since he wore practically no defensive armor, the retiarius was more mobile than most gladiators but was also more vulnerable to serious wounds. Looking at the retiarius in this mosaic, one has to ask, “Why is this man smiling?” because the secutor appears about to stab him.
• Bestiarius: This was a special type of gladiator trained to handle and fight all sorts of animals. The bestiarii were the lowest ranking gladiators; they did not become as popular or individually well known as other types of gladiators. Although this relief depicts bestiariiwearing armor, most depictions show them without armor, equipped with whips or spears, wearing cloth or leather garments and leggings.

(got information from www.vroma.org/~bmcmanus/arena.html )