Comments: PAT *śǝ-śǝ (cf. also Bz. a-śǝ́ś), pl. *śa-ra (Abkh. a-sá-ra, Bz. a-śá-ra, Abaz. sa-ra); -śǝ is the common suffix for names of young animals. PAK *śǝná.
External evidence suggests that -na is part of the root; reason for its loss in PAT is not quite clear. The correspondence PAT *ś : PAK *ś points unambiguously to PWC *śʷ.