If you can avoid, DON’t. Update to latest (6.5).
Out of laziness, this is a one-liner modern mode but the detail is is -Ba
gmt pscoast -Rg -JN0/27 -S255/255/255 -G155/200/155 -N1 -W0.75p -A10000 -Ba -png lixo
Also, don’t. Use psconvert instead.