  We investigate the representation theory of certain specializations of the
Ariki-Koike algebras, obtained by setting $q=0$ in a suitably normalized
version of Shoji's presentation. We classify the simple and projective modules,
and describe restrictions, induction products, Cartan invariants and
decomposition matrices. This allows us to identify the Grothendieck rings of
the towers of algebras in terms of certain graded Hopf algebras known as the
Mantaci-Reutenauer descent algebras, and Poirier Quasi-symmetric functions.
