FISHERY BULLETIN: VOL. 87, NO. 3, 1989 



prawns, and were later found to be in error. For 

 example, Heegard (1953) identified larvae from 

 plankton collections as Penaeus setiferus. How- 

 ever, the protozoea I figured has a 2nd antennal 

 setal formula of 0+2+2 and a wide telson notch, 

 characters not seen in Penaeus but consistent 

 vdth either Trachypenaeus or Parapenaeopsis. 

 The protozoea II figured has the same 2nd an- 

 tennal setal formula as the protozoea I, and the 

 form of the rostrum and supraorbitals are not 

 characteristic of Penaeus. However, this sub- 

 stage has supraorbital spines, which Trachy- 

 penaeus and Parapenaeopsis larvae do not. 

 Heegard's protozoea III is consistent with 

 Penaeus in some respects, such as the long ros- 

 trum, but its 2nd antennal setal formula is now 

 1+2+2, whereas the Penaeus formula is 1 + 1+2. 

 It is likely that the protozeae described are from 

 several genera, although the figures do not show 

 sufficient detail for an accurate identification. On 

 the other hand, Heegard's mysis figures are gen- 

 erally consistent with Penaeus, although the 

 specific identification is in doubt since P. az- 

 tecus, P. duorarum, and P. setiferus all exist in 

 the collection area. Similarly Dakin (1938) iden- 

 tified plankton-caught larvae as P. plebejus, but 

 they were probably a combination of Trachy- 

 penaeus (based on the relative lengths of the 1st 

 and 2nd antennae of protozoea III) and Meta- 

 penaeus (a 2nd antennal setal formula of 1+2+3 

 and telson with 7+7 spines in protozoea III). As 

 a final example, Subramanyam (1965) reported a 

 high density of penaeid eggs in the plankton off 

 the Madras coast, and identified them as P. 

 indicus after culturing several nauplius sub- 

 stages. However, the large egg diameter (0.45 

 mm) and large perivitelline space indicate that 

 the eggs were probably Trachypenaeus, since 

 Penaeus eggs have a diameter between 0.23 mm 

 and 0.31 mm and a narrow perivitelline space 

 (Dall et al. in press). 



Descriptions of the lesser known penaeid 

 genera from plankton samples may also be based 

 on mistaken identifications. The only pubhshed 

 description of larvae of the genus Penaeopsis is 

 of P. rectacuta (Paulinose 1973), but the author 

 gave no support for his choice of genus. The 

 larvae were collected from areas of the Indian 

 Ocean where species of other previously un- 

 described genera are common, including Atypo- 

 penaeus stenodactylus, Metapenaeopsis anda- 

 mensis, M. barbata, M. hilarula, M. nwgiensis, 

 M. philippii, and M. stridulans, all of which are 

 sufficiently abundant to support some com- 

 mercial fishing (Dall et al. in press). The present 



description of Metapenaeopsis palmensis has 

 much in common with several of the substages 

 described by Pauhnose (1973). The 2nd antennal 

 formula of 1 + 2+2, a reduced second supra- 

 orbital spine in protozoea III, the rostrum 

 length, the shape and spination of the mysis, and 

 the serrate anteroventral carapace margin of the 

 mysis substages are all consistent with M. 

 palmensis described in the present study. Proto- 

 zoea II is probably from a different genus, since 

 it has no supraorbital spines [in all penaeids 

 described except Macropetasma africanum 

 (Cockcroft 1985) the presence or absence of 

 supraorbital spines is the same for both pro- 

 tozoea II and III]. However, the figure of this 

 substage shows the 2nd antennal exopod (on the 

 whole animal) as symmetrical, with about 9 setae 

 along both the interior and the exterior borders, 

 whereas the drawing of the dissected appendage 

 shows the more typical penaeid form of 10 setae 

 along the inner border and 2 on the outer border. 

 More subtle characters may also have been 

 represented incorrectly, so confident identifica- 

 tion is difficult; however, the characteristics 

 shown (lack of supraorbital spines, a deep and 

 wide telson notch and a relatively short rostrum) 

 are consistent with both Trachypenaeus and 

 Parapenaeopsis. 



Paulinose (1986) described mysis I and II and 

 an early postlarva (which, because of lack of 

 setae on the pleopods, we call mysis III) from 

 the Indian Ocean. He tentatively identified it as 

 Atypopenaeus stenodactylus. However, these 

 larvae resemble our Metapenaeopsis pahnensis 

 and differ from our A. formosus in the following 

 important characters: rostrum length and shape 

 (long and curved); the presence of a serrated 

 anteroventral carapace margin; telson spine for- 

 mula (7+7 for mysis I, 7+1 + 7 for mysis II and 

 III) and abdomen spination (dorsal spines on the 

 fourth, fifth, and sixth segments and lateral 

 spines on the fifth and sixth segments). Al- 

 though there are some differences between M. 

 palmensis and the larvae described by Paulinose 

 (1986), we feel that these larvae are not Atypo- 

 penaeus but most likely an unidentified species 

 of Metapenaeopsis. 



Most recently, Paulinose (1988) described 

 mysis and postlarval stages of Metapenaeopsis 

 mogiensis, M. andamanensis, and M. barbata 

 from widely spread locations in the Indian 

 Ocean. Unfortunately, genus and species were 

 again assigned by comparison with known distri- 

 butions of adult prawn species, and by hnking 

 substages based on similarity of appearance. 



730 



