  We report the discovery of EPIC 201498078b, which was first identified as a
planetary candidate from Kepler K2 photometry of Campaign 14, and whose
planetary nature and orbital parameters were then confirmed with precision
radial velocities. EPIC 201498078b is half as massive as Saturn ($\rm
M_P$=$0.179 \pm 0.021$ $\rm M_J$), and has a radius of $\rm R_P$=$0.840 \pm
0.011$ $\rm R_J$, which translates into a bulk density of $ \rm \rho_P$=$0.37
\pm 0.05$ g cm$^{-3}$. EPIC 201498078b transits its slightly evolved G-type
host star ($\rm M_{\star}$=$1.105 \pm 0.019$ $\rm M_{\odot}$, $\rm R_P$=$1.669
\pm 0.022$ $\rm R_{\odot}$) every $11.63364 \pm 0.00010$ days and presents a
significantly eccentric orbit ($e=0.420 \pm 0.034$). We estimate a relatively
short circularization timescale of 1.8 Gyr for the planet, but given the
advanced age of the system we expect the planet to be engulfed by its evolving
host star in $\sim 1$ Gyr before the orbit circularizes. The low density of the
planet coupled to the brightness of the host star ($J=9.4$) makes this system
one of the best candidates known to date in the super-Neptune regime for
atmospheric characterization via transmission spectroscopy, and to further
study the transition region between ice and gas giant planets.
