Praetorian shield sizes\shape in the early third century

[Nathan Ross]

would not be unreasonable to say that the curved oval shields traditionally with bolts, stars and moon emblems would still be in use by the newly reformed guard.

Nobody knows for sure, but I would think it unlikely. The 'republican' equipment of the early praetorians was apparently a feature of the earlier empire, Julio-Claudians in particular; by the third century this would have appeared quite antique. None of the depictions of later praetorians show anything like that, as far as I'm aware.

It was actually Dio (79.37) who mentions the scale armour, and he also mentions 'grooved' or 'gutter shaped' shields (the shape of Roman lead guttering, perhaps?), which might refer to the traditional rectangular scutum.

The 'stars and moons' emblem comes, as far as I recall, from a Domitianic frieze from Puteoli. The earlier praetorians also used the scorpion as an emblem, which appears as late as Trajan. There's very little evidence for later insignia, but Ross Cowan (in Osprey's Roman Guardsman 62 BC–AD 324) suggests the lion with a radiate crown that appears on some coins of Gallienus dedicated to the praetorian cohorts might have been one of their emblems in later times.