Martines could possibly be Northern Italian, you get a lot of last names that don't end in a vowel with Northern Italians. My last name doesn't end in a vowel and my last name wasn't changed one single letter at all zip zero percent when my Grandfather left Northern Italy for New Jersey.
I don't think it's Northern. In North Italy this kind of surnames are basically the same as others but without the final vowel. Martines (or Martinez) sounds more like a Spanish surname.
