S.D. Codified Laws § 29A-2-705

Adopted individuals and individuals born out of wedlock, and their respective descendants if appropriate to the class, are included in class gifts and other terms of relationship in accordance with the rules for intestate succession. Terms of relationship that do not differentiate relationships by blood from those by affinity, such as "uncles," "aunts," "nieces," or "nephews," are construed to exclude relatives by affinity. Terms of relationship that do not differentiate relationships by the half blood from those by the whole blood, such as "brothers," "sisters," "nieces," or "nephews," are construed to include both types of relationships.