276 
Fishery Bulletin 99(2) 
Table 1 
Metapenaeopsis dalei. Chronology of embryonic devel- 
opment under laboratory conditions (24.0-26.0°C; 32.2- 
33.2 %o) 
Developmental stages 
Duration 
(hour: min.) 
Cumulative 
(hour: min.) 
1 cell 
00: 23 
00: 00 
2 cell 
00: 25 
00: 23 
4 cell 
00: 26 
00: 48 
8 cell 
00: 28 
01: 14 
16 cell 
00: 20 
01: 42 
32 cell 
00: 28 
02: 02 
64 cell 
00: 50 
02: 30 
Gastrula stage 
04: 50 
03: 20 
Early embryonic nauplius 
05:30 
08: 10 
Late embryonic nauplius 
06:30 
13: 40 
Embryonic nauplius just 
before hatching 
20: 10 
Table 2 
Metapenaeopsis dalei. Chronology of larval development 
under laboratory conditions (24.0-26.0°C; 32.2-33.2%D 
Duration 
Cumulative 
Larval stages 
(hour) 
(hour) 
First naupliar stage 
06 
006 
Second naupliar stage 
07 
013 
Third naupliar stage 
07 
020 
Fourth naupliar stage 
08 
028 
Fifth naupliar stage 
08 
036 
Sixth naupliar stage 
12 
048 
First protozoeal stage 
48 
096 
Second protozoeal stage 
60 
156 
Third protozoeal stage 
50 
206 
First mysis stage 
46 
252 
Second mysis stage 
26 
278 
Third mysis stage 
49 
327 
First postlarval stage 
119 
446 
the carapace to the midposterior margin of the carapace 
for zoeae, from the postorbital margin to the midposterior 
margin of the carapace for mysis and first postlarvae; body 
width (BW), the greatest width across the body for nauplii. 
Results 
Development of larvae and duration of the 
larval stage 
A gravid female of Metcipenaeopsis dalei spawned for two 
hours from 22:00 to 24:00. The egg was spherical and 
greenish grey, with a mean diameter of 0.35 mm (n=20). 
The nauplius hatched about 20 hours after spawning 
(Table 1). The larvae passed through six naupliar, three 
zoeal, and three mysis stages, before the postlarval stage. 
About 15 days (about 347 hours) were required from the 
hatching to the first postlarval stage (Table 2). 
Descriptions of larvae 
First naupliar stage (Fig. 1, A and B) 
Size TL: 0.37 mm (0.35—0.41 mm; SD=0.02; n = 12) 
BW: 0.23 mm (0.21-0.25 mm; SD=0.02; n=12) 
Body (Fig. 1, A and B ): Slightly oval in dorsal or ventral view, 
convex dorsally; anterodorsal median ocellus; posterior mar- 
gin rounded; one chitinous conical protuberance on postero- 
dorsal part of body; caudal end with one pair of setae; body 
unsegmented; three pairs of appendages with naked setae. 
Antennule (Fig. 1A): Uniramous; two terminal setae and 
four lateroventral setae. 
Antenna (Fig. 1A): Biramous; endopod with three termi- 
nal and two lateroventral setae; exopod with three termi- 
nal and three lateroventral setae. 
Mandible (Fig. 1A): Biramous; endopod and exopod each 
with one lateroventral and two terminal setae. 
Second naupliar stage (Fig. 1, C and D) 
Size TL: 0.43 mm (0.37-0.53 mm; SD=0.04; n=15) 
BW: 0.23 mm (0.16-0.27 mm; SD=0.03; n=15) 
Body (Fig. 1, C and D): Elongate oval in dorsal or ven- 
tral view; anterodorsal median ocellus; posterior margin 
rounded; posterodorsal protuberance absent; caudal end 
with two pairs of setae; three pairs of appendages with bi- 
pinnate setae; body unsegmented. 
Antennule (Fig. 1C): Unchanged. 
Antenna (Fig. 1C): Unchanged. 
Mandible (Fig. 1C): Unchanged. 
Third naupliar stage (Fig. 1, E and F) 
Size TL: 0.44 mm (0.42-0.45 mm; SD=0.02; n=6) 
BW: 0.24 mm (0.21-0.27 mm; SD=0.03; n= 6) 
Body (Fig. 1, E and F): Form unchanged; anteroventral 
median ocellus; posterior margin rounded; caudal end with 
two pairs of setae; body unsegmented. 
Antennule (Fig. IE): Uniramous; three terminal setae, 
outermost short and four lateroventral setae. 
Antenna (Fig. IE): Biramous; endopod with three termi- 
nal and three lateroventral setae; exopod with three ter- 
minal and three lateroventral setae. 
Mandible (Fig. IE): Unchanged. 
Fourth naupliar stage (Fig. 2, A and B) 
Size TL: 0.43 mm (0.40-0.47 mm; SD=0.03; n- 4) 
BW: 0.23 mm (0.22-0.24 mm; SD=0.01; 72=4) 
Body (Fig. 2, A and B): Slightly elongate; anteroventral 
median ocellus; medial notch dividing posterior end into 
two symmetrical lobes each with 3+3 setae; thoracic part 
with some rudimentary segmentation ventrally. 
