This is Z4,at 12 dah and 4mm.
The typical pp5 of Lysmata larvae show at this stage.They are very long legs which make a curve and point forward.The end is expanded and colored like paddles.They can be seen at the front of the larva,like two red spears.
Then come the antennula,(A1),which now are forked.They will be the first two pairs of antennae of the adult.
After them,two pairs of colored walking legs (mp3 and pp1) and three pairs of clear swimming legs (mp2,mp3 and pp1)can be seen.
At the rear end,endopods can be seen between the colored exopod and telson.This last is still fish tail shaped.