  We present new observational results on the kinematical, morphological, and
stellar population properties of a sample of 21 dEs located both in the Virgo
cluster and in the field, which show that 52% of the dEs i) are rotationally
supported, ii) exhibit structural signs of typical rotating systems such as
discs, bars or spiral arms, iii) are younger (~3 Gyr) than non-rotating dEs,
and iv) are preferentially located either in the outskirts of Virgo or in the
field. This evidence is consistent with the idea that rotationally supported
dwarfs are late type spirals or irregulars that recently entered the cluster
and lost their gas through a ram pressure stripping event, quenching their star
formation and becoming dEs through passive evolution. We also find that all,
but one, galaxies without photometric hints for hosting discs are pressure
supported and are all situated in the inner regions of the cluster. This
suggests a different evolution from the rotationally supported systems. Three
different scenarios for these non-rotating galaxies are discussed (in situ
formation, harassment and ram pressure stripping).
