Roman marines , or rather Boat assigned legionaries, the X Legion began as a marine legion if some of its legends are to be believed, or at least recruited from the Roman navy.
The Roman navy by the time of the Jewish revolt was a commerce protection force in the roman sea [Mediterranean] as the Med was enclosed by the empire, although a few pirates existed from time to time. In the North sea however the roman fleet was a full battle fleet with legionaries serving on their ships.
During the Jewish revolt the Jews converted their merchant ships into a commerce raiding force to attach roman supplies reaching the front, however the roman nave quickly secured all the ports preventing the Jewish ships from re-supplying and were run to ground or fled to Greek ports which at that time was an independent nation within the roman empire.
The Roman Navy landed marines along the Jewish coast and captured the forts along the trade routes. Their landing forces fought along side the hard pressed XIV legion and the X Legion when it moved up from Africa.
During the civil war the navy in Judea took little part until Otho was killed and Vitellius massacred the marines of the western fleet as their saluted him emperor. Then the eastern fleet declared for Vespasian [their overall commander in the Jewish Revolt] and the Fleet lest 3 detachments fighting in Judea and the rest of the fleet moved to Egypt to block forces loyal to Vitellius from taking Egypt.
They held out until Vespasian arrived in Egypt with elements of the X, XV and 'Sandhogs' Auxiliary guard of Herod's Syrians as well as Armenian troops, some transported by the fleet the rest marched down the coast. With the massacre of the marines in Italy the western fleet, even though been larger could do little to stop the smaller battle hardened eastern fleet. it may also be possible that the few fleet commanders remaining just did not want to fight for vitellius.
The Legionaries of X & Sandhogs [carried in Syrian warships of Herod's]secured the capital which had already declared for Vespasian [the local commander having served with Vespasian in Britain] and the Marines beached some of their craft to make a fort along the coast, the African forces besieged this AD/Hock defence which bought time for Vespasian to march down with the XV and Armenian troops and made Egypt his unofficial capitol.
From their he cut the grain supply to Rome and forces loyal to him and who had fought for Otho launched a full invasion of the Empire, moving by land across the top of Italy the army smashed Vitellius army moving on Rome. The marines of the navy landed to the south of Rome cutting off allied forces of Vitellius but did not take much part in the fighting, although a group of survivors of the massacre did take part in the final battle for Rome, hiding their uniforms under cloaks, along with some Vigiles who were loyal to Vespasian's murdered brother they opened the gates and let Vespasians troops into he city.
These troops are praetorians painted in light blue, for Mediterranean eastern navy, or as Syrian navy [same uniform] Dark blue for western navy, green for Northern fleet.
The shields are cavalry shields, easier to use on a ship where corners can get stuck. The shields are from Lancashire games and the figured warlord games.