weapons and armour of the greek marine

[hoplite14gr]

My opinion is that they were aware of various shield types.
Considering that tradition weighted heavily at that times I cannot argue that use of "exotic shields" would be widespread in mainland Greece but more probable in the armies of the colonies.

To clarify: I consider any non round shield "exotic" but what we perceive as "Greek shield" with exception of the "thracian shield" that was known from the bronze age (warrior vase.) .

And a question square shield in the West is 4th century B.C. as you say.
The same applies foe "eliptic" or other non round shield?
Kind regards