  Prompted by a recent lattice QCD calculation, we review the SU(3) light quark
flavor structure of charmed tetraquarks with spin-0 diquarks. Fermi statistics
forces the three light quarks to be in the representation 3*x3*= 3+6*. This
agrees with the weak repulsion in the 15 of the 3x8 in Dbar K scattering
studied on the lattice. We analyze the 3+6* multiplet broken by the strange
quark mass and determine the five independent masses from the known masses of
diquarks. The mass of D^* _{s0}(2317) is predicted within 50 MeV accuracy. The
recently observed D_s^{--}(2900) and D_s^{0}(2900), likely part of a I=1
multiplet, with flavor composition c* q* q' s and X_0(2900), an isosinglet with
flavor composition c*s* ud, fit naturally in a 3+6* structure as the first
radial excitations. We discuss also the decay modes of D^* _{s0}(2317), of the
radial excitations and of the predicted particles.
