  In recent years spiral structures have been seen in scattered light
observations and signs of vortices in millimeter images of protoplanetary
disks, both probably linked with the presence of planets. We present ALMA Band
7 (335 GHz or 0.89 mm) continuum observations of the transition disk HD135344B
at unprecedented spatial resolution of 0.16", using superuniform weighting. The
data show that the asymmetric millimeter dust ring seen in previous work
actually consists of an inner ring and an outer asymmetric structure. The outer
feature is cospatial with the end of one of the spiral arms seen in scattered
light, but the feature itself is not consistent with a spiral arm due to its
coradiance. We propose a new possible scenario to explain the observed
structures at both wavelengths. Hydrodynamical simulations show that a massive
planet can generate a primary vortex (which dissipates at longer timescales,
becoming an axisymmetric ring) and trigger the formation of a second generation
vortex further out. Within this scenario the two spiral arms observed at
scattered light originate from a planet at ~30 AU and from the secondary vortex
at ~75 AU rather than a planet further out as previously reported.
