HAYNES LARVAL MORPHOLOGY OF PANDALUS TRIDENS 



characteristics: species with exopodites on 

 pereopods 1-3 and species with exopodites only on 

 pereopods 1 and 2. Species with exopodites on 

 pereopods 1 and 2 are characterized by well- 

 developed pereopods in Stage I. and no spines on 

 the abdominal somites or denticles on the 

 carapace margin. For three of the species with 

 exopodites on pereopods 1 and 2 iPandalopsis coc- 

 cinata. P. dispar, and Pandalus kessleri), the 

 numbers of telsonic spines in Stage I are consider- 

 ably greater than for species with exopodites on 

 pereopods 1-3. 



Fewer thoracic exopodites usually indicate 

 fewer stages before the megalopa (Pike and Wil- 

 liamson 1964). This is not always true for pandalid 

 shrimp larvae of the North Pacific Ocean. For in- 

 stance, larvae of P. danae, P. hypsinotus, andPa«- 

 dalopsis dispar also bear exopodites on first and 

 second pereopods; but, the number of their larval 

 stages is 6, 7. and 7, respectively. Also, Stage I 

 larvae of P. dispar have dorsal and ventral teeth 

 on the rostrum, 12 + 12 spines on the telson, and a 

 long, jointed antennal flagellum that is about six 

 times the length of the antennal scale; but the 

 pleopods are not tipped with setae until Stage V, 

 and Stage VII zoeae still bear a supraorbital spine. 



A greater number of telsonic spines in Stage I is 

 associated with fewer larval stages in develop- 

 ment of the Caridea (Gurney 1942; Pike and Wil- 

 liamson 1964). This is true for Pandalus 

 platycer(>s,P. kessleri, and Paridalopsis coccinata . 

 which have 8 + 8, 16 + 16, and 28 + 28 telsonic 

 spines in Stage I and 5, 4, and 3 larval stages, 

 respectively. An exception is P. dispar, which has 

 12-^12 telsonic spines in Stage I, but may have as 

 many as seven larval stages. 



Four species of pandalid shrimp in the North 

 Pacific Ocean are not listed in Table 1: Pandalnp- 

 sis ampla, P. aleulica, P. longirostris , and 

 Dichelopaiidalus leptocerus. Larvae of P. amphi. 

 P. aleutica. and P. longirostris have not been de- 

 scribed. If larvae of P. ampla, P. aleutica, and P. 

 longirostris undergo typical development of larvae 

 of the genus Pan da I ops is (Kurata 1964; Berkeley 

 1930), they will be characterized by advanced de- 

 velopment, especially their large size and long 

 antennal flagellum. Stage 1 Pandalopsis spp. lar- 

 vae are at least 10.0 mm long and the antennal 

 flagellum is longer than the body and segmented 

 throughout its length. For comparison. Stage I 

 larvae oi' Pandalus are 8.0 mm or less in length 

 and the antennal flagellum is usually unseg- 

 mented and shorter than the length of the 



carapace. Stage I and II larvae of/), leptocerus 

 have been tentatively identified from western 

 Greenland waters (Pike and Williamson 1964). 

 The larvae identified as D. leptocerus are most 

 similar to larvae of P. stennlepis and P. platyceros: 

 in Stage I and II, D. leptocerus, P. stenolepis. and P. 

 platyceros bear prominent denticles on the antero- 

 ventral margin of the carapace, the anteroventral 

 margin of the carapace and posterior margin of the 

 third abdominal somite are flared, the rostrum is 

 about as long as the carapace, and exopodites are 

 present on pereopods 1-3. Larvae of D. leptocerus 

 can be distinguished, however, from the identified 

 pandalid shrimp larvae of the North Pacific 

 Ocean, including larvae of P. stenolepis and P. 

 platyceros , by the presence of posterolateral spines 

 on the fifth abdominal somite. 



LITERATURE CITED 



Bkhkki.ev. a. a. 



1930- The post-embryonic development of the common 

 pandalids of Briti.sh Columbia. Contnb. Can. Biol. 

 6:79-16.3. 



Gurney, R. 



1942. Larvae of decapod Crustacea. Ray Soc. iLond.i 

 Publ. 129, 306 p. 

 Haynes, E. 



1976. Description of zoeae of coonstripe shrimp. Pandalus 

 hypsumtus, reared in the laboratory. Fish. Bull., U.S. 

 74:323-342. 



1978. Description of zoeae of the humpy shrimp, Panrfa/u.s 

 goniurus. reared in situ in Kachemali Bay, Alas- 

 ka, Fish. Bull., U.S. 76:235-248. 



1979. Description of larvae of the northern shrimp, Pan- 

 dalus bitrealis. reared in situ in Kachemak Bay, Alas- 

 ka. Fish. Bull. US. 77:1.57-173 



IVANdV, B. G. 



1965. A description of the first larva of the far-eastern 

 shrimp {Pandalus goniurus). [In Russ., Engl, 

 summ.j Zool. Zh. 44:12.55-1257. iTransl. by U.S. Dep. 

 Commer., NOAA, Natl. Mar. Fish. Serv., Off. Int. Fish. 

 Affairs, Code No. F44,l 

 1971. The larvae of some eastern shrimp in relation to 

 their taxonomic status. [In Russ., Engl, summ.l Zool. 

 Zh, 50:657-665. (Transl. by U.S. Dep. Commer., NOAA, 

 Natl, Mar. Fish Serv,, Off, Int, Fish, Affairs. Code No. 

 F44.) 



Kurata, H 



1955. The post-embryonic development of the prawn, 

 Pandalus kessleri. |In Jpn., Engl, synopl Bull, Hok- 

 kaido Reg, Fish. Res, Lab, 12:1-15. 



1964. Larvae of decapod Crustacea of Hokkaido. 3, Pan- 

 dalidae. [In Jpn , Engl synopl Bull. Hokkaido Reg. 

 Fish, Res, Lab 28:23^34, 

 LEE, Y. J. 



1969. Larval development of pink shnmp, Pandalus jor- 

 dani Rathbun reared in laboratory. M.S. Thesis, Univ. 

 Washington, Seattle, 62 p. 



639 



