HAYNES: DESCRIPTION OF PANDALUS HYPSINOTUS ZOEAE 



STAGE III ZOEA 



Total length of Stage III zoea (Figure 3A) 6.7 

 mm (range 6.2-7.7 mm, 25 specimens). Chro- 

 matophore pattern similar to first two stages but 

 less yellow color and more reddish brown. Ros- 

 trum pointing slightly upward with one or two 

 small teeth at base. Supraorbital, antennal, and 

 pterygostomian spines still present on carapace. 



ANTENNULE (FIGURE 3B).— Outer flagel- 

 lum distinctly three segmented; first and second 

 segments have two groups of three aesthetascs 

 each; distal segment has four aesthetascs. Inner 

 flagellum still bisegmented but about twice as 

 long as in Stage II. Remainder of antennule simi- 

 lar to Stage II except it is larger and more setose, 

 and lateral projection on proximal segment is 

 more arcuate. 



THIRD MAXILLIPED (FIGURE 3G).— Similar 

 in shape to third maxilliped at Stage II but larger 

 and more spinous and propodite bears two small 

 spinulose spines. Numbers of setae on endopodites 

 of maxillipeds and pereopods on this and succeed- 

 ing stages are so highly variable that a specific 

 description of them would not be an aid in 

 identification of stage or species. 



FIRST PEREOPOD (FIGURE 3H).— Exopodite 

 still present, more setose than Stage II. Propodite 

 bears a small spinulose spine near base. Pleu- 

 robranchia at base of this appendage and remain- 

 ing four pereopods barely larger than in Stage II. 



SECOND PEREOPOD (FIGURE 31).— Most 

 significant changes are presence of chela on 

 endopodite and an additional segment on base of 

 ischiopodite. 



ANTENNA (FIGURE 3C).— Antennal scale 

 with 32-36 lateral plumose setae; no segmenta- 

 tion at tip in this or later stages. Lateral margin 

 near base now has four additional simple setae. 

 Flagellum about 3 times length of scale; has 

 several additional segments and setae near base. 



THIRD (FIGURE 3J), FOURTH, AND FIFTH 

 PEREOPODS.— Essentially similar; fifth small- 

 est as usual. Greater development from Stage II 

 shown by well-formed dactylopodite and more 

 setae. An additional segment occurs at base of 

 ischiopodite. 



MANDIBLES (FIGURE 3D).— Both mandi- 

 bles without palps. Right mandible bears three 

 premolar processes; projections along anterior 

 molar edge stronger and truncated end not 

 curved into lip as in Stage II. Left mandible 

 molar processes also stronger, and subterminal 

 processes present. 



MAXILLULE (FIGURE 3E).— Endopodite un- 

 changed from Stage II except two setae particu- 

 larly spinulose. Basipodite bears an additional 

 plumose seta and a group of small fine hairs sub- 

 terminally. Coxopodite now bears 14 instead of 12 

 setae and has more fine hairs than Stage II. 



MAXILLA (FIGURE 3F).— Exopodite longer 

 than in Stage II, slightly curved, and bears 27 

 marginal plumose setae in addition to plumose 

 seta at proximal end. Lobes of basipodite bear 10 

 setae instead of 9 as in Stage II. 



FIRST AND SECOND MAXILLIPEDS.— Epi- 

 podite on first maxilliped has rudiment of second 

 lobe. Otherwise, first and second maxillipeds 

 same as Stage II but slightly larger. 



PLEOPODS (FIGURE 3A).— Pleopods evident 

 as small buds. 



TELSON (FIGURE 3K).— Uropods free; bear 

 plumose setae and small, randomly located setae 

 on dorsal surface. Telson broader at tip than at 

 base and still slightly emarginate; bears seven 

 pairs of spinous setae and two pairs of lateral 

 spines. Base of telson bears a pair of simple setae 

 that increase in number in later stages and persist 

 in adults. Anal spine appears at this stage. 



STAGE IV ZOEA 



Total length of Stage IV zoea (Figure 4A) 7.5 

 mm (range 7.3-8.1 mm, 10 specimens). Chromato- 

 phore pattern and color considerably different 

 from previous stages. In general, numerous small 

 wine-red chromatophores occur on carapace, pere- 

 opods, and ventral surface of abdomen; small yel- 

 low chromatophores occur on carapace, anten- 

 nules, antennal scale, uropods, telson, and third 

 abdominal segment. Rostrum beginning to ac- 

 quire adult shape; 11-13 dorsal spines, 2 or 3 small 

 ventral spines, and 1 dorsal spine that may be 



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