  We report on a novel kind of small scale structure in molecular clouds found
in IRAM-30m and CSO maps of 12CO and 13CO lines around low mass starless dense
cores. These structures come to light as the locus of the extrema of velocity
shears in the maps, computed as the increments at small scale (about 0.02 pc)
of the line velocity centroids. These extrema populate the non-Gaussian wings
of the shear probability distribution function (shear-PDF) built for each map.
They form elongated structures of variable thickness, ranging from less than
0.02 pc for those unresolved, up to 0.08 pc. They are essentially pure velocity
structures. We propose that these small scale structures of velocity shear
extrema trace the locations of enhanced dissipation in interstellar turbulence.
In this picture, we find that a significant fraction of the turbulent energy
present in the field would be dissipating in structures filling less than a few
% of the cloud volume.
