  Recently it has been shown how a topologically twisted version of ${\cal
N}=4$ super Yang-Mills may be discretized in such a way as to preserve one
scalar supersymmetry at nonzero lattice spacing. The remaining fifteen
supersymmetries are broken by terms of ${\cal O}(a)$ where $a$ is the lattice
spacing. One would like to know whether these remaining supersymmetries are
regained in the continuum limit $a \to 0$ and, if not, how much tuning of the
couplings in the lattice action is required. In this paper we derive the form
of these additional twisted supersymmetries by combining a set of discrete
R-symmetries of the continuum theory with the action of the scalar
supersymmetry. We then argue that restoration of rotational symmetry in the
continuum limit of the lattice theory likely implies restoration of R-symmetry
and hence should lead to an automatic enhancement to the full ${\cal N}=4$
supersymmetry without further fine-tuning.
