  We are investigating the SF in galaxies of the actively evolving Dorado group
where signatures of interactions and merging events are revealed by optical and
radio observations in both ETGs and LTGs. Our previous Ha+[NII] study, probing
~10 Myrs timescales, suggested that SF is still ongoing in ETGs. In this work,
we use far-UV (FUV) imaging to map recent SF on times scales of about 100 Myrs.
We used the Ultraviolet telescope UVIT on board Astrosat to image the Dorado
backbone galaxies previously observed in Ha+[NII], with the far-UV filter
FUV.CaF2 (1300-1800A). The sample includes NGC1536, NGC1546, NGC1549,
[CMI2001]4136-01, NGC1553, IC2058, PGC75125,NGC1566, NGC1596 and NGC1602.
FUV.CaF2 emission is revealed in all galaxies, tracing young stellar
populations in rings and showing tidal distortions. The Sersic index, derived
by fitting the luminosity profiles, is always n<3 suggesting that the FUV.CaF2
emission originates from a disk also in ETGs. The SFR ranges from 0.004+-0.001
M_sol yr^{-1} of [CMI2001]4136-01 to 2.455+-0.027 M_sol yr^{-1} of NGC 1566.
Most of the recent SF is found at the periphery of the Dorado group where most
of LTGs are located. For these galaxies, the ratio SFR_Ha/SFR_FUV.CaF2 is close
to 1, except for the edge-on IC 2058, similarly to previously reported
relations for Local Volume samples. For ETGs, however, SFR_Ha is about 15 times
higher than SFR_FUV. The Dorado's ETGs define a separate locus in SFR_FUV,
SFR_Ha space with respect to the LTGs, which is well represented by the
relation log (SFR_FUV.CaF2) = 0.70xlog (SFR_{Ha})-1.26.The disk structure of
the FUV.CaF2 emitting populations discovered in all the ETGs implies
dissipative processes and wet merging events. The systematic discrepancy
between SFRs derived from Ha and FUV fluxes suggests that rejuvenation episodes
in ETGs cannot sustain constant SF over ~100 Myrs timescales.
