Sotiate etymology

Hello

something about Sotiate (aquitanian tribe) etymology ?



Soto = cellar in Basque (Gascon)

Cesar says in bello Gallico that Sotiates know perfectly make undergroung passage during the siege of the town and mine too



may be Sotiates = Soti-ates = miners (?)

but Soto come from Latin Subtulus = under (?)