Euclidean superconformal symmetry and its relation with Minkowski supersymmetries

We write down the extended D = 4 euclidean superconformal algebra SL(2, N; H) in quaternionic as well as complex notation. Only for even N the analytic continuation of the Minkowski conformal supersymmetry SU(2, 2; N) to the D = 4 euclidean conformal supersymmetry does exist. The (noncompact) euclidean internal symmetry group is Usup(*) (2 N). The euclidean anti de Sitter and de Sitter extended supersymmetries are discussed also. (orig.)