  We present first results on the octet and decuplet strange baryon spectrum
with $N_f=2+1+1$ twisted mass quarks. We use an Osterwalder Seiler valence
strange quark with a mass tuned to the kaon and compare the results with those
obtained in the unitary setup. This comparison allows to perform a first study
of the lattice artefacts introduced by the mixed action approach. We
investigate the effect of the strange and charm quarks in the sea by using two
lattice spacings and comparing with preceding $N_f = 2$ twisted mass fermion
calculations.
