  We consider partial spontaneous breaking of N=1 AdS4 supersymmetry OSp(1|4)
down to N=1, d=3 Poincare supersymmetry in the nonlinear realizations
framework. We construct the corresponding worldvolume Goldstone superfield
action and show that it describes the N=1 AdS4 supermembrane. It enjoys
OSp(1|4) supersymmetry realized as a field-dependent modification of N=1, d=3
superconformal symmetry and goes into the superfield action of ordinary N=1,
D=4 supermembrane in the flat limit. Its bosonic core is the Maldacena-type
conformally invariant action of the AdS4 membrane. We show how to reproduce the
latter action within a nonlinear realization of the AdS4 group SO(2,3). The
same universal nonlinear realizations techniques can be used to construct
conformally-invariant worldvolume actions for (d-2)-branes in generic AdSd
spaces.
