Is there an historical feminine counterpart to Anglo-Norman 'Fitz' (as in surnames such as Fitzgerald, Fitzroy, et al.)? My Googling hasn't been productive except to confirm that it's an abbreviation of Latin 'filius', the feminine form of which would be 'filia'. Browsing through the archive here I turned up a post from 5 years ago where a responder suggested Fitz was used by either sex, but the link to further information she had offered has expired.
Thanks for your time.