Extra gauge symmetries in R + T2 gravitational theories

We investigate a class of gravity lagrangians which are linear in curvature and quadratic in torsion terms. It is found that for special cases these theories are invariant with respect to local transformations beyond general coordinate and Lorentz transformations. These additional invariances are worked out explicitly and their relevance is discussed. The 'gravity with extra gauge symmetry' by Bars and McDowell turns out to be just one example. (orig.)