I have a question for the resident history buffs on the board.

When were certain types of Roman arms & armor first used/incorporated by the Roman Army?

IIRC, Roman armor included (essentially) a chain shirt, (possibly) a scale mail shirt, & the famous lorica segmentia (essentially banded mail for the torso & shoulders). There is also the square shield & reinforced helmet. Were there other types used earlier/later? Am I roughly accurate w/ what I mentioned?

As for arms, I'm familiar with the gladius (short sword), pilum (javelin), pugio (dagger), & spatha (long sword for cavalry). Anything I missed?

Appreciate any help I can get.