  We point out that meson spectrum indicates the existence of a degenerate
chiral nonet in the energy region around 1.4 GeV with a slightly inverted
spectrum with respect to a qq nonet. Based on this observation, the
approximately linear rising of the mass of a hadron with the number of
constituent quarks, and the existence of a cuasidegenerate pseudoscalar nonet,
we conjecture the existence of a tetraquark chiral nonet in this energy region
with chiral symmetry implemented directly. We realize this idea in a chiral
model and take into account the mixing of the tetraquark chiral nonet with a
conventional qq nonet. We find that the mass spectrum of mesons below 1.5 GeV
is consistent with this picture. In general, pseudoscalar states arise as
mainly qq states but scalar states turn out to be strong admixtures of qq and
tetraquark states.
