FISHERY BULLETIN: VOL. 72, NO. I 



Table 3. — Ontogenetic development in copepodite stages of Pontellina. 



Ill 



IV : 



IV, 



V • 



Thoracic segments 

 Free abdominal segments 

 Rostrol filaments 

 Dorsal ocelli 

 Right Al 



PI Re segments 

 Ri segments 



P2 Re segments 

 Ri segments 



P3 Re segments 

 Ri segments 



P4 Re segments 



Ri segments 

 P5 Re segments 



Ri segments 



corresponding stage of female, but P5 with Ri 

 absent or appearing as a small distal swelling 

 on B2. Right Re also slightly larger than left. 



Stage V Female 



(Figure 17a-l) 



TL 1.18-1.48 mm (40 specimens, all species 

 represented). ThIV and V almost completely 

 separated. Urosome with 3 segments, genital 

 segment largest and with weak ventral swelling. 

 Furcal rami incompletely separated from anal 

 segment. Lateral margin of right furcal ramus 

 proximal to first seta lacking protrusion. Left 

 and right Al symmetrical. Re of P3 and P4 

 trimerous, Ri bimerous. P5 with proportions of 

 Re and Ri showing similarity to those of adult. 

 Re unimerous with 5 setae on right leg, 6 setae 

 on left leg; proximal Si of left side notable for 

 its size and curved shape, an asymmetry lacking 

 in the adult. 



Stage V Male 



(Figure 18a-q) 



TL 1.20-1.44 mm (40 specimens, all species 

 represented). ThIV and V almost completely 

 separated. Urosome with 4 segments. Furcal 

 rami incompletely separated from anal segment. 



0.2 mm 



a -c 



Figure 16. — Pontellina sp. copepodite stages: a. stage 

 IV female, P5, anterior view; b. stage IV male, P5, 

 posterior view; c. stage III copepodid, P5. 



Right Al with segments 13-16 slightly swollen, 

 segments distal to swelling partly fused. P5 

 trimerous, slightly curved medially; right leg 

 longer than left leg, Ri not developed. 



In other genera of Pontellidae, as well as in a 

 number of other heterarthrandrid families 

 (Diaptomidae, Temoridae, Centropagidae, Pseu- 

 dodiaptomidae) we note that fusion of urosomal 

 segments I and II in the female first appears in 

 the stage V copepodid (Gurney, 1931; Johnson, 

 1935; Crisafi, 1960; Lawson and Grice, 1970; 

 Grice, 1971). Morphological features of the geni- 

 tal plate, antrum, and internal structures such 

 as the seminal receptacles (Fahrenbach, 1962; 

 Frost and Fleminger, 1968) are lacking in the 

 stage V female. We also note that in most 

 amphascandrid families (e.g., Calanidae, Para- 



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