Developmental Stage of Peneaus Monodon

8/3/2019 Developmental Stage of Peneaus Monodon

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I IL a r v a l d e v e l o p m e n t PENAEUS MONODON F A B R I C I U S

E. G. Si lasM . S . M u t h u

N. N . P i j i a iK . V . G e o rg e

Penaeus monodon, the g ian t t iger p r aw n, has spawn ed in the Narakka l Praw n C u l tu r e Labora to ry o fthe CMFR I and la rvae have been reared to the juve n i le s tage. At a rear ing temper a ture o f 26 .5 C to28 .5C the nau p l i i ha tched ou t o f the eggs 16-1 7 hours a f te r sp aw nin g ; the na up l ius s tage lasted 40- 55hours; the dura t i on o f p ro tozoea stage was 4 i - 6 days and the mysis s tage lasted fo r 3 -6 days. The la rvepassed th ro ugh 6 naup l ius, 3 p ro tozoea and 3 mysis substages be fore becom ing post la rva 1 . The de ta i le : !

s t ruc tu re o f the la rva l subs tages is descr ibed and i l lus t ra te d in th is paper.

Penaeus monodon, the g ian t t ige r p raw nspaw ned in the Prawn Cu l tu re Labora to ry a tNarakkal and th e larvae we re reared up to juve ni lestage. Al though the larva l h istory o f th is specieshas been s tud ied by Vi i la luz e t . a l . (1969 ,Philippine J. Sci., 9 8 ( 3 - 4 ) : 2 0 5 - 2 3 3 ' ) a tPh i l ipp ine s, the f igure s are not c lear eno ughto show the de ta i l s o f se ta t ion . The ob jec tof th is paper is to i l lustra te and describe indeta i l the mo rph olog ica l characters o f the larva lstages of th is mos t imp orta nt species of penaeidp r a w n , so that they can be read i ly com pare dw ith the other species of Penaeus alreadydescr ibed . The rearing temp erature was 26.5 c

to 28 .5 ' ' c and the3 0 . 2 % - 3 3 . 5 % , .

sa l in i ty o f the wa te r

DESCR IPT IO N OF DEVEL O PM EN T AL ST AG ESEGGS

The eggs (F ig , l .a ) a re sma l l w i th a na rrowper iy i te l i ine space. The egg d iameter variedfrom 0.25 to 0 .27 mm and the yo lk mass 0.22to ( ' .24 mm . The rad ia t ing je l ly l ike substanceseen in the case of P. indicus is also presen t inthe fresh ly la id eggs of th is species. Thedeve lop ing n aup l ius a lmost f i l l s up the en t i respace ins ide the egg . The eggs ha tched ou t16 -1 7 hours a f te r spa wn ing .

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NAUPLIUS IMTL: 0-31 mm (0.29-0.32 mm); IVIW: 0.17 mm(0.17-0.18 mm ); MFS: 0.12mm (0.10-0.1 3m m):

Furcal setae 1 + 1 ; minute posterodorsaltooth present; all setae non-plum ose; A1 w ith2 inner lateral setae distal one longer thanproximal, 2 long setae and 1 min ute setalrudimen t term inally and 1 long seta on outerdistal m argin ; A2 exopo d bears 5 long setaealong inner and distal margin, endopod w ith 2short inner lateral setae and 2 long setae and aminute setal rudiment term inally; Md w ith 3long distal setae on exo and endopods (Fig .1. b) . D uration of this substage was 3 -4 hours.

F i g . 1 Penaaus monodon: a - egg ; b - nau pl ius I ;c - naup l i us I I ; d - M d o f naup l i us I I ; e - nau p l ius I I I ; f - nau pl ius IV; g - Md of nau pl ius IV

NAUPLIUS I IMT L: 0 .3 2mm (0 .3 1 -0 .3 2 mm) ; M W : 0 . i ; m m(0.17-0 .18mm); MFS: 0 .14mm.

Furcal setae l - f l ; posterodorsal to oth

absent; setae plum ose; outer term inal and outerlateral setae of A1 shorter than in previousstage, setal rudiment has become a sho rt seta; asetal rudime nt added to distal outer a ngle ofA2 exopo d, the 4th seta from proxim al endbifurcate distal to characteristic bend, thisparticular seta remains bifurcate in all subsequent nauplius substages (Fig , 1, c,d ).Duration of this substage was 3-4 hours.

NAUPLIUS I I IMTL: 0.33mm (0.31-0 .34 mm ); MW : 0.17mm(0.17-0 .18mm ); MFS:0.18mm (0 .17-0 . 20mm ).

Furcal setae 34-3 (Fig.1 ,e); inner term inalsetae of A1 longer than ou ter term inal seta,outer'lateral seta very thin and sho rt, a minuteseta added proxima l to 2 exis ting inner lateralsetae, A2 exopod w ith 6 plumose setae and asetal rudim ent, in endop od setal rud imen thas grown into a short non-plumose seta.Duration of this substage was 4-5 hours.NAUPLIUS IV

MTL: 0.36 mm (0.34-0.36 mm) ; MW : 0.19 mm(0.18-0.21m m); MFS: 0.20mm (0.18-0.21mm ).Furcal setae 4 + 4 (Fig. 1,f), fron tal organsseen, outer distola teral sela of A1 lost, inner

terminal seta longer; A2 exopod w ith faintsegm entation, setal rudim ent has become ashort seta and another setal rudim ent addedtermina lly, a minute seta also added proxima llyon inner ma rgin, in end opod inner term inal setalonger and plumo se and another setal rud imen tadded termina lly; base of Md swollen (Fig .1,g). Du ration of this substage was 5-6hours.NAUPLIUS V

MTL: 0.39 mm (0.36 - 0.41 mm );MW:0.18m m;MFS: 0 .25 mm (0 .2 2 -0 .25 mm).Furcal setae 6 f 6; A1 wit h m inute setaadded on outer lateral ma rginop posite to originof long distal inner lateral seta, faint segmen tation seen in proximal half; A2 exopod w ithoutermos t seta longer but sti ll non-plum ose(Fig.2,a). Duration of this substage was10-12 hours.

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MTL: 0.49mm (0.18mm)

N AU PL IU SVImm (046-0 .53 mm ) ; MW: 0 .200.20 mm ); MPS: 0.30 mm (0.28 -0.32

Furcal setae 7 + 7 (Fig.2, b), frontal organprominen t, carapace rudiment seen, 2 shortsetae added to outer distal margin of A 1 ,these 2 setae and the short term inal setaappear to be aesthaetes, the mid dle oneequidistant from other 2; A2 exopod w ithproxim al setal rudime nt of previous stagelonger, another setal rudiment added proximalto it, a setal rudiment added on outer margin

inside cuticle , exopod and endop od empty(Fig.2,c ). Duration of this substage was15-24 hours.PROTOZOEA I

MTL: 1.06 mm0.47 mm (0.44 (1.05 - 1.090.49 mm). mm); MCLFrontal organs rounde d; telson (Fig.3,a)wi th 7 + 7 setae, outermost pair dorsallydispose d, 3rd pair from inner margin offurcal lobes characteristically sigm oid, furcallobes broad and short w it h sem icircular spacebetween them.

F i g - 2 Penaeus monodon: a - n a u p l i u s V ; b - n a u p li u sV I ; c - Md o f naup l ius V I ; Pro tozoea I ; d - M d;e - M x l

proxim ally, endopod wi th 4 terminal setae,3 long and one short, a short seta addedto base of distal inner lateral seta wh ichhas become longe r; Md wi th basal swe llingvery promine nt, c utting blade of Md seen

A1 (Fig.3,a) wi th 3 main segments,proximal one subdivided into 5 subsegments,basal segment w ith 1 short inner seta, m iddlesegment wi th 1 long and 1 medium innerlateral setae and 1 short outer lateral seta,distal segment termin ally w ith 2 long setae, 1short seta and 3 aesthaetes, 1 of wh ich appearsto be s ubterm inal; A2 (Fig.3,a) wi th 9-10segmented exopod bearing 11 setae alon g innerand distal margin and 2 short setae on outermargin, endopod 2 segmented, distal segmentwi th 5 terminal setae, one of w hic h is short,proxim al segment has 3 inner lateral setae,2 dista l, 1 in m iddle and l at jun ction ofendopod wit h protopo d; Md (Fig.2,d) almostsymmetrical with 1 free standing tooth betweenincisor and molar processes; M x l (Fig.2,e)protopod wi th 2 endites, distal w ith 1 slenderand 3 stout setae and proximal w ith 6 setae,exopod w ith 4 feathery setae, endopod 3segmented, distal segment w ith 5 long terminalsetae, middle with 2 long setae and basalw ith 3 setae, 2 long and 1 short; Mx 2 (Fig.3,b)protopod with~5 endites; basal endite wi th 6setae and others w ith 3-4 setae, exopod wi th5 feathery setae, endopod wi th 4 indistinctsegments, distal wit h 3 long setae and restw ith 2 lateral setae each; M xp l (Fig.3,c)protopod w ith 2 indistinc t segments bearingnumerous setae, endopod 4 segmented, 1stwit h 3 setae, 2nd wit h 1,3rd wi th 2 and 4thw ith 5 setae, exopod unsegmented wi th 7plumose setae; Mxp 2 (Fig.3,d) protopo d wi th 2ind istin ct segments bearing 7 inner lateralsetae, endopod indis tinctly divided into 4segments, 1st segment with 2 setae, 2nd with 1,

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3rd w ith 2 setae and 4th w ith 5 setae, exopodw ith 6 setae; IV!xp3 absent. Du ration of th issubstage was 36 -48 hours.f it into the concavity on right M d; Mx 1 (Fig.4,c)distal endite w ith 7 setae; no change in Mx pland Mx p2; Mxp 3 absent. Durat ion of thissubstage was 36-48 hours.

Fig- 3 Penaeus monodon:b - IVlx2; c - M xp lM d.

Protozoea I; a - dorsal vie w;d - Mxp 2; protozoea II ; e -

PROTOZOEA IIMCL : 0.72 mm (0,70-0.77 m m); MT L: 1.06 mm(1.65-1.68 mm).

Carapace (Fig.4,a) with long ventrallybent rostrum and bif id supraorbital spines,telson w ith 7 pair sof furcal setae; A1 (Fig.4,a),one hair like seta added to mid dle segment onouter ma rgin; A2 (Fig .4, a) setae have becomelonger; Md (Fig.3,c) asymmetrical, left w ith5 free standing teeth and right w ith 1 freestanding too th, m olar surface of right Mdappears to have a conca vity w ith the rim pro duced into a number of crenulate teeth , m olar

itsurface of left Md not concave but coveredw ith number of toothed ridges and appears to

0.05mm

Fig. 4 Penaeus monodon: Protozoaa II ; a - dorsalv i ew ; b - A 1 ; c - M x l ; d - Mx p l ; P ro tozoeaI I I : e - Md; f - Mxp2; g - M


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4,e) right IVld w ith 2 and left w ith 6 freestanding teeth ; IVlxl .(Fig .5,b)d istal endite w ith10 setae and proximal w ith 7 setae; Mx 2(F ig.5,c), more setae added to endites; Mx pl(Fig.5,d) one inner lateral seta added to 2ndsegment of endopod , expood wi th 2 additionalsetae; Mx p2 (F ig.4 ,f), an outer lateral setaadded to 1st segment of end opo d, 1 moreseta added to exo pod; Mx p3 developed ,

pterygostom ial and hepatic spines present;abdominal segments 3-6 wit h dorsomedianspines, 5th and 6th w ith prominent posterolateral spines, 6th wi th prominent posteroventralspines also, curved ventrom edian spine presentat junc tion of 6th abdominal segment w ithtelson, minute pleopod buds on abdominalsegments; telson (Fig.5,g) w ith 8 + 8 shortstout setae, cleft deep reaching ha lfway betweenlevel of ori gin of 2 pairs of outer lateral setae.

A1 (Fig.6,b ) 3 segmented, basal segmentw ith anteromedian ventral spine, 2 setae abovestylocerite rudiment, outer f lagellum wi th 5

Fig. 5 Penaeus monodon: Protozoea II I: a - dorsalview; - IVlxl; c - Mx2; d - Mxpl; e - uropod.Mysis I; f - uropo d; g - telson.as biramous bud (Fig .4,g), endopod rudimentw ith 2-3 setae. Duration of this substage was36-48 hours.

MYSIS IMCL: 1.18 mm (1.14-1.23 mm ); MTL: 3.79 mm(3.65 - 3.96 mm).

Carapace (Fig.6,a) w it h rostrum longerthan eye, no rostral too th , supra orbital.

Fig. 6 Penaeus monodon MysIs I: a - lateral view ;b - A I ; c - A2; d - Wld; e - M x l ; f - M x2;g - P3

aesthaetes and 3 setae, inner flage llum min utewi th 2 setae, 1 long and 1 short; A 2 (Fig.6,c),exopod unsegmen ted, fringe d w ith 11 setae oninner and distal margin, and a plumose outerdistolateral seta, endopod tipped w ith 3 shortsetae; Md (Fig.6,d), r ight w ith 3 and left with7 free standing teeth, palp not seen; M xlLARVAL DEVELOPMENT OF PENAEID PRAWNS


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(Fig.6,e) e xopo d retaine d; IVIx2 (Fig .6,f) 10setae on exopo d; M xp l (Fig.7,a) lexopod w ith12 setae; Mx p2 (Fig.7,b ) outer lateral setaeadded to 1st and 2nd segment of endo pod;Mxp3(Fig.7,c) well developed,'with 5 segmented

Fig-7 Penaeus monodon: Mysis I : a - M xp l ; b -Mxp2; c - Mxp3; d - P I; e - P4. Mysis I I :f - A2; g - M x1 ; h - uropod; i - lelson.endopod, exopod t ipped wi th 6 setae (1 + 4 + 1 ) ,some t imes 5 setae ( 0 + 4 f 1 ) ; PI to P3 (Fig7.d; 6,g) with endopod 2 segmented, w ith incipientchela, t ipped w ith 4 long setae and one innerlateral seta, exopod w ith 7-8 setae ( 2 + 4 + 1 or2 + 4+ 2) ; P4a nd P5(Fig,7,e) endopod t ippedwi th 3 terminal setae, exopod w ith 7 or 8 setae;uropod (Fig.5,f), exopod with prominentdistolateral spine follow ed by a short nonplumoseseta shorter than distola teral spine and 16-17long plumose setae; endopod w ith 16 longplumose setae. Dura tion of th is substage was24 to 48 hours.

MYSIS IIMCL:1.39mm (1.34 to 1.47 mm) MTL: 4.16 mm(3.90-4.37 mm).

Rostrum usually wit ho ut teeth, rarely aminute too th may ba present, no change inspina tion of carapace and abdomen (Fig.8 ,a),pleopods short, unsegmented; telson w ith cleftreaching to level of orig in of penu lt imate pair ofouter setae (Fig.7,i).A1 (Fig.8, b) inner f lagellum 3/4 length ofouter; A2 exopod (Fig.7,f) with 19 plumose setaeand a prominent distolateral spine, endopodunsegmented t ipped w ith 2 short setae; Md(Fig.8,c) w ith 3 and 7 free standing teeth onright and left Md respectively, palp develop ed;M x l (Fig.7,g) with ou t exopod, distal enditewith 12 and proximal with 8 setae; Mx2 with16 setae on exopod (F ig.8,d); Mx pl (Fig.8,e) w ith

Fig. 8 Penaeus monodon: Mysis II : a - lateral view;b - A1 ; c - Md ; d - Mx2 exopod; e - Mxpl ;f - Mxp2; g - Mxp3; h - P I; i - P4; j - distolateral port ion of exopod of uropod,12 setae on exopod, rarely with 13 setae; Mxp2.(Fig.8,f) en dopod w ith penult imate segmentindis t inctly divided into 2, distal segment w ith6 setae, exopod w ith 4 terminal setae; Mxp 3

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(Fig.8,gi exopod w ith 0 + 44-1 or 1+4-1-1 setae;PI to P3 (Fig.8,h) endopo d 2 segmented,distal segment indistinc tly divided into 3,chela developed w it h 2 termina l setae and 3short setae at jun ctio n of dactylus w it hpropodus,- 1 short seta on inner ma rgin of 1stsegment, exopod wi th 1+ 4+ -2 or 2 + 4+-2long plumose setae; p4 and p5 (Fig.B.i,)endopod 2 segmented, distal segment indistinctlydivided into 2, tippe d w ith 3 setae 1st segmentw ith 1 short outer seta, 2nd w ith 1 outerseta and 1 Inner; uropod (Fig.7,h), endopodwith 20 plumose setae, exopod with 18plumose setae and 1 nonplum ose seta shorterthan prominen t distolateral spine (Fig.8 ,j)Duration of this substage was 24-48 hours.

MYSIS 111MCL: 1.40mm (1.32-1.51 mm ); M TL: 4.24mm(4.00-4.40mm).

Fig. 9 Penaeus monodon: Mysis II I: a - later al view ;b - A I ; C - A2 ; d - Md ; e - M x l ; f - exopodof Mx2; g - Mx pl; h - Mxp2; I - Mxp3; k - P4;I - uropod; m - telson.

Rostrum w ith 1 too th in some specimens,no change in spination of carapce and abdomeniFig.9,a ; pleopods long, 2 segmented withoutsetae; cleft in telson reaching level of orig inof 3rd pair of outer lateral setae on telson(f ig.9,m).Al (Fig.,9b) with flagella unsegmented,moreor less equal in le ng th, outer w it h 7 aesthaetesand 2 setae, inner wi th 3 apical setae; A2(Fig.9,c) w ith 22-23 plumose setae and aprominent distolateral spine, endopod 2 segmented ; Md (Fig.9,d) with palp longer, right and leftMd w ith 3 and 7 free standing teethrespectively; M x l (Fig.9,e) w it h 13 setae ondistal endite; Mx2 with 22 setae on exopod(Fig.9 ,f); M xp l (Fig.9,g) wi th gil l rudiment onprotopod, exopod with 12, rarely 13 setae;Mxp2 (Fig.9,h) no appreciable change; Mxp3

(Fig 9,1), endopod longer tha n ex opod w hic hhas 1 + 4 + 1 or 0 + 4 + 1 setae; PI to P3 (F ig .9,j) w ith 5 segmented endopod, we ll formedchelae retain th e long setae; P4 and P5 (Fig.9,k) w ith 5 segmented endo pod, distal segmentw ith 2 apical setae, 4th segment w ith 1inner and 2 outer setae, 3rd w jth 1 outerand 1 inner setae, 2nd w ith no seta and1st w ith one inner seta; uropod (Fig.9,1wi th 22 plumose setae on endopod, exopodwith 20 plumose setae and 1 non-plumose setashorter than distolateral spine. Duration of thissubstage was 24 to 48 hours.INTERMEDIATE STAGE

MCL: 1.50mm (1.48-1.53 mm ); MTL: 4.54 mm(4.49-4.59 mm).Rostrum wi th 1 distinct too th; no changein spination of carapce and abdomen (Fig. 10,a);pleopod (Fig. 10,k) w ith 10 plumose setae;exopods of Mx p2, M xp3 and PI to P5 w ithplumose setae; shallow cleft of telson stil lpresent (Fig.10,1).A l (Fig.10,b) w ith 3 segmented inner

flagellum wh ich is longer than 2 segmentedouter f lagellum ; A2(Fig .10,c)endo pod 6 segmented tipped with 5 setae, exopod with 23 plumosesetae and prominent distolateral spine; Md (F ig.10 , d) free standing teeth absent, palp un-segmented, w ith 4 setae; M x l (Fig . 10,e) noappreciable change; Mx2 (Fig.10,f) w ith 19 to20 plumose setae on exopod; Mxpl (10,g) exopodand endopod reduced in size, protopod segmentsLARVAL DEVELOPMENT OF PENAEID PRAWNS


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enlarged, gil l rudiment developed; Mxp 2(Fig.10,h) endo pod sig mo id, setae reduced inlength; Mxp3 endopod longer than exopo d,exopod setae stil l present; PI to P3 (Fig.10 ,i)chela fully developed witho ut long terminalsetae; exopods sti l l with setae,; P4 to P5 (Fig.

F i g . 1 0 Penaeus. monodon - In te rm ed ia te s tage : a -l a te r a l v i e w ; b - t i p o f A 1 ; c - A2 ; d - M d ;e - M x l ; f - M x 2 ; g - M x p l ; h - IV Ix p 2; i -P 1 ; j - p4 ; l< - p le op od ; I - te ls on .

lOJ) endopods with out long terminal setae,exopods retain the setae; uropod wi th 23plumose setae on en dopod, exopod wit h 22plumose setae and 1 nonplum ose seta shorterthan prom inent distolatera l spine Dura tion ofthis substage was 24 to 30 hours.POSTLARVA 1

MCL: 1.46 mm (1.40-1 .54 mm), MTL : 4.56 mm(4.45-4.70 mm).Rostrum w ith 1 dist inct too th, supraorbitalspine reduced in size, no change in spination

of carapace and abdome n (Fig.11,a) pleopodssetose (Fig.11,1) exopods on Mx p2, Mx p3,p i to p5 shrunken, with out setae; shallowcleft in telson sti l l present (F ig .l l. b ).A1 (Fig.11 ,b) 3 segmented inner flagellum

twi ce as long as 2 segmented outer f lagellu m;A2 (Fig.11,c) endopod 6 segmented, exopodwith 25 plumose seta and prominent distolateral spine; Md (Fig.11 ,d) cutt ing edgedeveloped, palp 2 segmented, short distalsegment with 2 and longer proximal segmentw ith 4 setae; M x l (Fig.11,e) setae on distalendite short and stout, endopo d reduced insize, without setae; Mx2 (Fig.11,f) exopod0. ; mm

F i g . 11 Penaeus monodon: Post la rva I : a - lateralv i e w ; b - A 1 ; c - A2 ; d - M d ; e - M x l ; f -M x 2 ; g - M x p l ; h - M x p 2 ; i - M x p 3 ; j - P I ;K - P3 ; I - p leo pod ; m - u rop od ; n - u rop od ,d is to la te r . - l ang le ; o - te ls on .

wi th 24 setae, endopod unsegmented reducedin size; M xp l (Fig.,11g) protopod enlarged,exopod and end opod unsegmented. reducedin size, endopod with ou t setae, exopod wi thC M FR I B U LLET IN 28 9


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single outer seta; Mx p2 (Fig.1 1,h) recurvedendopod w ith stout setae on distal segment,exopod shrunken w itho ut setae; Mxp 3 (F ig.11,1) shrunken exopod w itho ut setae; p i top3 (Fig.11,j,k) chela functional, without longterminal setae, exopod vestigia l; p4 and p5exopod vestigial; uropod (Fig.11,m ), endopodwit h 25 plumose setae, exopod wi th 22

plumose setae and 1 nonplum ose seta shorterthan distolateral spine (Fig l l .n).DISCUSSION

The present larval description of P. monodon,differs from that gjven by Vil laluzi in somerespects. The differences are tabula tedbe low:

Nauplius IA 1

P. monodon(Present)

distal inner lateral seta long

P. monodon(Vi l la luz ')

distal inner lateral seta shortA 2

Nauplius IIA 1

endopod w ith 4 setae, 2 innerlateral, 2 long terminal, a setalrudiment present terminally

1 long and 2 short terminalsetae, 1 short oute r lateral setaand 2 longer inner lateral setae

endo pod w ith 3 setae, 1 inner lateral, and2 long terminal

1 short and 2 long terminal setae, longouter lateral and 2 short inner lateral setae

A 2 endopod with 2 long setae and1 setal rudiment at t ip and 2short inner setaeendopod wi th 2 long and 1 short seta attip and 1 sh ort inner lateral seta

Nauplius IIIA 1 7 setae, 2 long and 1 short att i p , 2 long and 1 minute oninner margin and 1 very thinouter lateral

5 setae, 3 long at tip and 2 .longat sides

A 2 endopod w ith 5 setae 2 longand 1 short at t ip and 2 shortinner lateralenopod w ith 6 setae, 3 long at t ip and 3short inner lateral

Nauplius IVA 1 6 setae, 2 long and 1 short att ip and 2 long and 1 short

inner lateral5 setae, 3 long at tip an d 2 short at sides.

A 2 exopod w ith 9 setae, 2 long, 1short and 1 rudimentary at t ip,4 long and 1 rudimentary oninner lateral m arg in; segmentsnot dist inct ; endopod with 6setae, 3 long and 1 rudimentaryat tip, 2 short at side

exopod with 7 setae, 2 long and 2 shortat t ip and 3 long on inner margin,segments dist inct, endopod w ith 5 setae,3 long at tip and 2 short at side

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Nauplius VA 1 7 setae, 2 long and 1 short att ip , 2 long and 1 rudimentaryon inner lateral side and 1rudimentary on outer lateral

6-7 setae, 2 long and 1 short at tip and3-4 short at side; 2-3 t iny spines atsides

A 2Nauplius VIA 1

A 2

Protozoea IM x l

M x p l

exopod segments not clear

9 setae, 2 long and 1 short att ip and 2 short and 1 rudimentary on outer lateral side, 2 longand 1 rudimentary on innerlateral side, segmentation notclearexopod with 12 setae, 2 long,1 short and 1 rudimentary at t ip ,5 long, 1 short and 1 rudime ntary on inner marg in, and 1rudimentary on outer margin,segmentation faint, endopodw ith 6-7 setae, 3 long and 1short at t ip and 2- 3 short oninner margin

6 setae on proximal endite and4 setae on dista l end iteendopod with 3, 1, 2 and 5setae

exopod wi th 8 segments

6-7 setae; 2 long and 2 short at t ip and2-3 short at sides, 2-3 t iny spines atsides, 9-1 1 short basal segments

exopod w ith 10 setae. 3 long and 1 shortat tip and 4 long and 2 short at sides; 9segments, endopod with 6-7 setae, 4 longat tip and 2-3 short at side

7 setae on proximal endite and 5 setae ondistal enditeendopod w ith 2-3 setae on each of f irst3 segments and 5 distal segments

ProtozoeaM x l

ProtozoeaMxp1Mxp2

Mysis 1M x p lUropod

II

III

6 setae on proximal endite and7 on distal endite

9 setae on exopod7 setae on exopod

exopod w ith 12 setae17-1 8 setae on exopod and 16

7 setae on pro xima l end ite and 5 setae ondistal endite

7 setae on exopod6 setae on exopod

setae on endopod

exop od same as in protozoea stage16-1 7 setae on exopod and 15-1 6 setaeon endopod

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Mys/'s IIA 2Uropod

Mysis IIIA 1

A 2IVIx2

Postlarva 1uropod

exopod with 19 setaeexopod with 19 setae,endopod w ith 20 setae

outer and inner flage llum notsegmentedendopod 2 segmentedexopod with 22 setae

endopod wi th 25 and exopodwith 23 setae

exopod with 17-18 setaeexopod wi th 19-21 setae, endopod wi th17-19 setae

outer f lagellum with 2faintsegmentat ions,inner wi th 3 faintsegmentat ionsendopod wi th 4 faint segm entsexopod with 19-20 aetae

endopod wit h 22-23 and exopod with21-22 setae

The intermediate stage described here is rare and is probably a de via tion 'rom the normalnot mentioned by Villa luz ef. a/. ' . Even during course of larval developme nt,the present study the intermediate stage was

Date post:	06-Apr-2018
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Developmental Stage of Peneaus Monodon

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