  We present a novel twistor formulation of the ten-dimensional massless
superparticle. This formulation is based on the introduction of pure spinor
variables through a field redefinition of another model for the superparticle,
and in the new description we find that the super-Pauli-Lubanski three-form
naturally arises as a constraint. Quantization is studied in detail for both
models and they are shown to correctly describe the $D = 10$ super-Yang-Mills
states.
