  We investigate punctured maximum rank distance codes in cyclic models for
bilinear forms of finite vector spaces. In each of these models we consider an
infinite family of linear maximum rank distance codes obtained by puncturing
generalized twisted Gabidulin codes. We calculate the automorphism group of
such codes and we prove that this family contains many codes which are not
equivalent to any generalized Gabidulin code. This solves a problem posed
recently by Sheekey in [30].
