Examples of D=11 S-supersymmetric actions for point-like dynamical systems

A non standard super extensions of the Poincare algebra (S-algebra [1,2]), which seems to be relevant for construction of various D=11 models, are studied. We present two examples of actions for point-like dynamical systems, which are invariant under off-shell closed realization of the S-algebra as well as under local fermionic $\kappa$-symmetry. On this ground, an explicit form of the S-algebra is advocated.