42 



S. KARAYTUG AND G.A. BOXSHALL 



in copepodids. Body width is given as the widest part of the 

 nauplius body or the copepodid cephalothorax. In the spine and 

 seta formula of the swimming legs Roman numerals and Arabic 

 numerals are used for spines and setae respectively. 



When necessary scanning electron microscopy (SEM) was 

 used to study fine details. Material for SEM was prepared by 

 cleaning specimens in an aqueous solution (one drop in 100 ml 

 of distilled water) of the surfactant detergent RBS pF for 30 min 

 and subsequently sonicating in an ultrasonic cell disrupter for 7 

 s. Cleaned specimens were washed in 3 changes of distilled water 

 for 5 minutes, dehydrated through a graded acetone series, 

 critical point dried, mounted on aluminium stubs, sputter 

 coated with gold and viewed under an Hitachi S-800 scanning 

 elctron microscope. 



RESULTS 



Description of Naupliar Stages 



Nauplius I 



Body length : mean ± standard deviation = 1 1 8 ± 2.68 urn (range 

 1 1 3 to 1 22 um, n=20), mean body width 75 ±1.5 um (range 72 to 

 77 um, n=20). Body oval (Fig. 1A), with posterior spinular row 

 on ventral surface and on either side of caudal setae. Ventral 

 surface with 2 paired patches of spinules posterior to labrum. 

 Oval area of integument located posteriorly on ventral surface. 

 Caudal rami represented by pair of naked setae. 



Antennule 3-segmented (Fig. 2A). First segment with 1 

 spinulose seta anteriorly and group of spinules along outer 

 margin. Second segment with 2 setae, distal one spinulose and 

 slightly shorter than proximal plumose one; ornamented with 2 

 spinular rows along ventral side. Third segment with 2 naked 

 setae distally and 2 spinular rows along ventral margin. 



Antenna biramous (Fig. 3 A), with 2-segmented protopod 

 comprising coxa and basis. Coxal gnathobase represented by 

 large spine armed with spinular row distally. Basis with 3 small 

 setae along inner margin, 2 of them closely set together in 

 proximal third. Exopod 4-segmented; segment 1 large with 1 

 spinulose seta and spinular row on outer margin; second 

 segment with 1 long naked seta; third segment with 1 long naked 

 seta and few tiny spinules on outer margin; fourth segment with 

 naked seta proximally and 1 long spinulose seta plus 1 naked seta 

 distally; outer margin with spinular row near proximal seta and 

 single isolated setule apically. Endopod unsegmented; armed 

 with 2 short inner setae and 2 long setae terminally. 



Mandible (Fig. 4A) biramous, with 2-segmented protopod 

 comprising small coxa and large basis. Coxal gnathobase with 1 

 naked seta. Inner margin of basis with 1 spinulose and 1 naked 

 seta; outer margin with minute spinule. Exopod 4-segmented; 

 first to third segments each with 1 plumose seta at inner distal 

 angle; segments 3 and 4 with spinular row along outer margin; 

 apex of fourth segment with long plumose, inner seta and short, 

 naked, outer seta, the latter about as long as segment. Endopod 

 2-segmented; first segment with two spinulose setae and spinular 

 row on inner distal margin; second segment with 4 naked setae. 



Nauplius II 



Body length : mean ± standard deviation = 1 35 ± 7.84 um (range 

 1 13 to 144 um, n=21), mean body width 88 ±4.5 um (range 83 to 

 100 um, n=21). Body similar to first nauplius but larger and 

 elongated caudally (Fig. IB); differing as follows: labrum (Fig. 



19C) with some spinules along lateral margin. Caudal region 

 lacking spinular row adjacent to caudal setae. 



Antennule (Fig. 2B) armed with third seta on inner terminal 

 edge of distal segment. Antenna (Fig. 3B) with additional small 

 seta at base of large sword-shaped coxal gnathobasic seta. Basis 

 with distal spinular row. Exopod 6-segmented, with 1 extra seta 

 located on minute second segment (arrowed in Fig. 16A). 

 Terminal segment of first nauplius subdivided; segment five with 

 1 naked seta and additional spinular row distally. Endopod of 

 antenna with 2 plumose setae of equal size and 1 shorter 

 plumose seta terminally, plus 2 inner lateral naked setae. 



Coxa of mandible (Fig. 4B) with unilaterally spinulose seta. 

 Additional naked seta present on inner margin of basis. First 

 segment of endopod with one naked seta and one longer 

 plumose seta but with no spinular row on inner distal margin. 

 Second segment of endopod with 4 naked setae and 1 plumose 

 seta. Base of first exopodal segment with additional naked seta. 



Maxillule appearing as strong plumose seta (arrowed in Fig. 

 IB). 



Nauplius III 



Body length : mean ± standard deviation = 158 ± 6.08 um (range 

 155 to 168 um, n=14), mean body width 105 ± 8.7 um (range 88 

 to 117 um, n=14). Body (Fig. 1C) similar to second nauplius but 

 larger, differing as follows: lateral spinular row on labrum 

 consisting of much stronger spinules. Caudal margin with pair 

 of strong plumose setae adjacent to longer naked setae. 

 Posterior end of body trilobate. 



Third segment of antennule (Fig. 2C) acquiring extra naked 

 seta on inner margin. Sixth exopodal segment of antenna (Fig. 

 3C) with 1 naked inner seta, 1 strong spinulose subapical seta 

 and 1 long spinulose apical seta. Mandible with minor changes 

 in relative lengths of endopodal setae (Fig. 4C). 



Nauplius IV 



Body length : mean ± standard deviation = 181 ± 8.4 um (range 

 166 to 192 um, n= 14), mean body width 1 25 ± 8.7 um (range 113 

 to 144 um, n=14). Body (Fig. ID) pear-shaped, differing from 

 Nauplius III as follows: caudal margin with pair of minute 

 spines representing Anlagen of caudal setae. Posterior end of 

 body trilobate and becoming elongated. 



Antennule (Fig. 2D) with a longer row of dentiform spinules 

 distally on first segment. Third segment with 2 additional naked 

 setae, plus extra row of long spinules midway along lateral 

 margin. 



Coxa of antenna (Fig. 3D) with spinular row midway along 

 outer margin. Basis with 4 setae along inner margin; outer 

 margin with 2 spinular rows on anterior surface and 1 spinular 

 row on posterior surface. Apical segment of exopod with 

 spinular row distally. 



Basis of mandible with few mid-anterior surface spinules. 

 Fourth segment of exopod with additional small seta distally 

 (Fig. 4D). 



Maxillule (Fig. ID) bilobed with 2 spinulose and 1 naked seta 

 on inner lobe. Outer lobe with 1 spinulose, 1 plumose and 1 long 

 naked seta. 



Nauplius V 



Body length : mean ± standard deviation = 210 ± 8.49 um (range 

 194 to 226 um, n=14), mean body width 138 ± 12.08 um (range 

 122 to 157 um, n=14). Body (Fig IE) similar to nauplius IV, 

 differing as follows: third pair of caudal setae larger. 



