Nihonotrypaea petalura (Stimpson, 1860)

Nihonotrypaea petalura (Stimpson, 1860)

( Figs 1–12 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 )

Remarks. We made several attempts to rear the larvae of Nihonotrypaea japonica and N. petalura in the laboratory. It turned out that the larvae N. japonica were very unpretentious, it survival rate in the laboratory was about 100%. Zoeae from all parent females always passed through five stages before molting to the megalopa. At the same time, the mortality of the larvae of N. petalura at earlier stages was high, caused probably by adhesion to water surface (this fact was also noted by Konishi with co-authors). At the end of experiment we have surprisingly found that sixth zoeae of this species molt not to the megalopa but to the next zoeal stage. Thus, all larvae of N.

petalura passed through not only six but even through seven zoeal stages before molting to the megalopa. At 22–23°C the first megalopa was attained 26 days after hatching.