HAVNKS: PANnAl.lDAK. mi'l'dl-VTIHAE. ANDCKANCONIDAK LAKVAK 



Telson narrows posteriorly, distjil margin 



convex Stage VI 



(first juvenile stage) 



Pandalus prensor Stimpson 



Five larval stages. 



Stages I-V (larvae) and VI-IX (juveniles), known 



parentage; figures 2-7 in Mikulich and Ivanov 



(1983). 



Abbreviated larval development characterized by 

 marked heterochrony in development of appendages. 

 In all described stages, supraorbital spine absent; 

 antennal flagellum segmented; antennal scale not 

 jointed at tip; pereopods developed. In Stage I, 

 rostrum curves ventrally between eyes; telson 

 discoid and jointed with abdominal somite 6; 

 natatory setae on exopodites of maxillipeds 1-3 and 

 pereopods 1-2. Length: Stages I-V, carapace length 

 1.42-1.75 mm. Range: coastal waters of southern 

 Okhotsk Sea, Sea of Japan, and southeastern Siberia 

 (Vladivostok and Possjet Bay); depth, 2-93 m 

 (Holthuis 1976; Mikulich and Ivanov 1983). 



Key X. — Larval stages of Pandalus prensor. 



1. Eyes sessile; rostrom bends ventrally be- 

 tween eyes Stage I 



Eyes stalked; rostrom straight 2 



2. Rostrum does not extend to anterior margin 

 of eye; telson discoid; uropods enclosed 



Stage II 



Rostrum extends beyond anterior margin of 

 eye; telson rectangular; uropods free 3 



3. Pleopods uniramous and unsegmented; tel- 

 son with 7 pairs of terminal spines .... Stage III 

 Pleopods (pairs II- V) biramous and segment- 

 ed; telson with ^ 5 pairs of terminal spines ... 4 



4. Ventral rostrum with 4 teeth; telson with 5 



pairs of terminal spines Stage IV 



Ventral rostrum with 6 teeth; telson with 3 

 pairs of terminal spines Stage V 



Pandalus stenolepis Rathbun 



Six larval stages. 



Stages I and II, known parentage; Stages III-VII 

 (Stage VII, first juvenile), from plankton; figures 

 1 and 2 in Needier (1938); figure 73 in Gurney 

 (1942; Page 208 verifies subterminal seta on 

 maxillule). 



In Stages I-IV, carapace flares laterally, lateral 

 margin with denticles; abdominal somites with 

 spinules and flared laterally. P^laring, size of den- 

 ticles, and spinules decrease in Stages II-IV. In 

 Stage I, pereopods tucked under carapace; telson not 

 jointed with abdominal somite 6; and flagellum of 

 antenna longer than antennal scale. Pleopods absent 

 until Stage III. Length: Stages I-VI, 6.0-14.0 mm. 

 Range: Unalaska Island, AK, to Hecata Bank, OR; 

 depth, 49-229 m (Butler 1980). 



Key XI. — Larval and first juvenile stages of Pandalus 



stenolepis. 



1 . Eyes sessile; rostrum without teeth .... Stage I 

 Eyes stalked; rostrum with teeth 2 



2. Rostrum with only dorsal teeth (4-5 teeth); 



uropods enclosed Stage II 



Rostrum with dorsal and ventral teeth; 

 uropods free 3 



3. Rostrum with 8 or 9 dorsal teeth and 2 ven- 

 tral teeth; pleopod buds only slightly cleft 



Stage III 



Rostrum with > 9 dorsal teeth and > 2 ven- 

 tral teeth; pleopods biramous 4 



4. Unjointed pleopods without setae .... Stage IV 

 Jointed pleopods with setae 5 



5. Right and left pereopods 2 with endopodites 

 of same length; pleopods with a few setae; 

 each endopodite without an appendix interna 



(Fig. IN, ai) Stage V 



Right and left pereopods 2 with endopodites 



of different lengths; pleopods setose; each 

 endopodite with an appendix interna 6 



6. Carapace with supraorbital spine; setose 

 exopodite on each pereopod Stage VI 



(megalopa) 

 Carapace without supraorbital spine; naked, 



vestigial exopodite on each pereopods 



Stage VII 



(first juvenile stage) 



Pandalus tridens Rathbun 



Probably 8 larval stages. 



Stage I, known parentage; Stages I-VII, from 



plankton; figures 1-7 in Haynes (1976). 

 Stage I, known parentage; figure 1 in Ivanov 



(1971). 



273 



