If Spanish Flamenco was influenced by Arabic music, then why are there no quarter tones in Flamenco?

Did Arabic music develop quarter tones after the Moors left Spain, or did quarter tones just become obsolete in Flamenco? I've heard the singing of Northern Spain, and this seems more likely to be the main influence, along with other forms of singing along the Mediterranean such as Crete. Seems like Arabic (Moorish) of course left its mark, but always puzzled at the lack of quarter tones in Flamenco.