Superstatistics permits the calculation of the Feynman propagator of a
relativistic particle in a novel way from a superstatistical average over
non-relativistic single-particle paths. We illustrate this for the Klein-Gordon
particle in the Feshbach-Villars representation, and for the Dirac particle in
the Schroedinger-Dirac representation. As a byproduct we recover the worldline
representation of Klein-Gordon and Dirac propagators, and discuss the role of
the smearing distributions in fixing the reparametrization freedom. The
emergent relativity picture that follows from our approach together with a
novel representation of the Lorentz group for the Feshbach-Villars particle are
also discussed.Comment: 25 pages, revtex 4, minor change