OCD(4) p.129, 'Aquila Romanus' (by Michael Winterbottom). He is the author of a surviving treatise On Figures of Thought and Speech.
Syrianus' commentary on Hermogenes often cites a Neoplatonic philosopher named Aquila who wrote on rhetorical subjects; he could well be this man. Also, Flavius Sosipater Charisius cites a passage of C. Iulius Romanus which quotes a work of an Aquila, On the ten categories of Aristotle; this may be the same man as well. He would have lived in the third or early 4th century AD.