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Fishery Bulletin 99(2) 
Figure 12 
Metapenaeopsis dcilei. First postlarval stage: (A) first pereiopod; (B) second pereiopod; (C) third pereiopod; (D) fourth 
pereiopod; (E) fifth pereiopod; (F) first pleopod; (G) second pleopod; (H) third pleopod; (I) fourth pleopod; (J) fifth 
pleopod. Scale bar = 0.2 mm. 
Telson (Fig. 11J): Pointed, with seven pairs of setae, one 
posteromedian spine, and numerous fine setae on surface. 
Discussion 
Jackson et al. (1989) and Dali et al. (1990) used labora- 
tory-reared and field-caught larvae, respectively, for their 
keys to the larvae and postlarvae of the penaeid genera. 
The protozoeal stages of the genus Metapenaeopsis can be 
distinguished easily from those of other genera by the 2nd 
antennal formula, mobile eyes, presence of strong spines 
above the frontal organ, and the body length. The mysis 
and postlarval stages are easily seperated from those of 
other genera by the serrated anteroventral margins of the 
carapace and unique thoracic sternal plate spines (2, 2, 0, 
0 , 0 ). 
The first naupliar stage of M. dalei bears a chitinous 
conical protuberance on the posterodorsal aspect of the 
body. The cephalic knobs described for M. stridulans and 
M. barbata are also present from 3rd naupliar to 6th nau- 
plius stages (Chong and Sasekumar, 1994; Ronquillo and 
Saisho, 1997). The protozoeal stages of M. mogiensis, M. 
andamanensis, M. palmensis, M. stridulans, M. barbata, 
and M. dalei have similar orbital or supraorbital spines, a 
telson setal formula of 7+7 and antennal setation of 0, 1; 5, 
5 or 0, 1; 4, 5. However, five dorsomedian abdominal spines 
are found on the abdomen of the 3rd protozoeal stage of 
M. dalei, but three in M stridulans and M. barbata. The 
mysis and postlarval stages of M. palmensis, M. stridu- 
lans, M. barbata, and M. dalei are similar in general ap- 
pearance, but some differences are found in the posterior 
ventral serrations of the carapace, in the number of setae 
on the scaphognathite and scaphocerite, and the thoracic 
sternal plate spines. Comparative morphological charac- 
teristics of M. palmensis, M. stridulans, M. barbata, and 
M. dalei are listed in Table 3. 
The important morphological characters of the first 
postlarva of M. dalei that distinguish it from the rest are 
1 43 scaphognathite setae on maxilla; 
2 three scaphocerite spines on outer margin of antenna; 
and 
3 sternal plate spines: 2, 2, 0. 1, 1. 
