It is possible that other distinct dialect groups were already in existence during this period. Good candidates are the hypothethical ancestor languages of Alanian/Scytho-Sarmatian subgroup of Scythian in the far northwest; and the hypothetical "Old Parthian" (the Old Iranian ancestor of Parthian) in the near northwest, where original *dw > *b (paralleling the development of *ćw).
What may have also been in use at the time? Precursors of what subset of Scythian are theorized to have existed? What possible predecessor of Pathian is thought to have existed?