HAYNES: DESCRIPTION OF PANDALUS HYPSINOTUS ZOEAE 



STAGE VI ZOEA 



Total length of Stage VI zoea (Figure 6A) 10.8 

 mm (range 10.0-11.8 mm, 10 specimens). General 

 color wine-red, particularly on carapace and per- 

 eopods and along ventral abdomen; remainder of 

 telson greenish hue. Most appendages of this 

 stage differ in shape only slightly from those of 

 Stage V and succeeding stages and are not 

 figured in detail. Rostrum with 15-19 dorsal teeth 

 in addition to 1 (usually) but sometimes 2 dorsal 

 teeth near acute tip; 4-7, usually 5, ventral teeth. 

 A seta may occur between two or three dorsal 

 teeth (Figure 6A). 



ANTENNULE. — Inner flagellum six segmen- 

 ted (rarely five). Outer flagellum eight segmen- 

 ted; bears seven (rarely eight) groups of three 

 (usually) aesthetascs each. 



ANTENNA. — Antennal scale fringed with 40- 

 45 plumose setae; flagellum about 6 times length 

 of scale. 



MANDIBULAR PALP.— Three segmented; 

 number of setae variable; setation formula — 6-8, 

 2-3, and 1-3. 



MAXILLULE. — Endopodite unchanged from 

 Stage V. Basipodite bears about 20 setae and 13 

 spines; coxopodite bears 18 setae. 



MAXILLA.— Exopodite fringed with 61 or 62 

 plumose setae. Three setae on endopodite. Seta- 

 tion formula of lobes of basipodite and coxopodite 

 21-22, 17-19, 2, 11-12. 



FIRST MAXILLIPED.— Exopodite has 10 or 11 

 setae along proximal margin. Setation formula of 

 endopodite 2, 4, 5. Number of setae on protopodite 

 variable — 38-61 on basipodite, 7-12 on coxopodite. 



SECOND MAXILLIPED.— More setose than in 

 preceding stages; about 50 setae on terminal 

 segment. No podobranchia. 



THIRD MAXILLIPED.— No exopodite. Arthro- 

 branchia as two minute rounded buds. 



FIRST PEREOPOD.— No exopodite. Arthro- 

 branchia bud at base of each pereopod except fifth. 



SECOND PEREOPOD.— No exopodite; carpal 

 joints of left and right pereopods 19 and 7 or 8 

 respectively. Left and right meropodites with 

 three or four and one or two joints respectively. 



THIRD, FOURTH, AND FIFTH PEREOPODS. 

 — Meropodite bears 4-6 spines. Fifth pereopod 

 bears neither bud of arthrobranchia nor epipodite. 



PLEOPODS (FIGURE 6B).— All five pairs 

 segmented, biramus, and tipped with setae but 

 nonfunctional. Appendix interna small bud on in- 

 ner lamella of second and third pleopods only. 



TELSON (FIGURE 6C).— Telson shows, for 

 first time, narrow shape similar to adult and 

 bears three pairs of dorsolateral spines. Terminal 

 margin rounded slightly; bears three pairs of 

 feathered spines and a pair of large setae 

 dorsally. Three pairs of stiff setae at base of 

 telson instead of two as in Stage V. 



POSTZOEAL STAGES VII-IX 



Total length of Stage VII zoea 12.1 mm (range 

 11.5-12.8 mm, four specimens). Pleopods func- 

 tional and appendix interna distinct on all 

 pleopods except first pair. Because abdominal 

 propulsion is evident at this stage, it is consid- 

 ered the first postzoeal (megalopa) stage (Wil- 

 liamson 1969). Dorsal rostral spines 19 or 20, 1 or 

 2 at acute tip; 7 or 8 ventral spines. Seta (usually 

 1, rarely 2) occurs between each pair of rostral 

 spines. Bud of podobranchia distinct, arises at 

 base of epipodite of second maxilliped; buds of 

 arthrobranchiae on third maxilliped distinct, 

 pointed. Telson bears four pairs of spines along 

 lateral margin, rarely an additional small spine 

 on either margin. Left and right carpal joints of 

 second pereopods 24 or 25 and 10 respectively. 



Stages VIII and IX differ only slightly from 

 VII. Total length of Stage VIII zoea 12.4 mm 

 (range 11.1-13.0 mm, four specimens). Gill buds 

 more fully developed in VIII than in VII but not 

 yet lobulated. Left and right carpal joints of 

 second pereopod 28 and 10 or 11 respectively. 

 Total length of Stage IX zoea 13.6 mm (range 

 13.4-13.8 mm, three specimens). Rostrum with 

 one to three setae between dorsal rostral spines 

 and one to five setae between ventral spines; seta 

 between the two spines at rostral tip. Buds of 

 both podobranchiae and arthrobranchiae nearly 

 lobulated. 



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