DEVELOPMENT OF PELAGIC LARVAE AND POSTLARVA OF 



SQUILLA EMPilSA (CRUSTACEA, STOMATOPODA), WITH AN 



ASSESSMENT OF LARVAL CHARACTERS WITHIN THE SQUILLIDAE 



Stkvkn G. Moki;an' anu Anthony J. Pkuvkn/.ano, Jh.' 



ABSTRACT 



Larvae of the predator\' crustacean .S't/fn/Za enipusa were collected from the plankton in Chesapeake 

 Bay and reai^ed in the laboratory to permit description of the pelagic stages before the postlarval stage. 



Characters such as rostral length and spinulation, carapace spinulation. relative size of telson, 

 overall body size, and appearance probably are of more value for specific than for generic identification- 

 The presence or absence of teeth on the dactylusof the second maxilliped. the presence or absence of a 

 spine on the basis of the second maxilliped. and the number of epipods may be useful characters in 

 determining generic alliances of larvae belonging to the Squill idae, but present data are not adequate 

 for construction of generic keys to stomatopod larvae. 



Mantis shrimps are formidable predators, able to 

 slice a swimming shrimp in half or smash open a 

 bivalve with enlarged second maxillipeds (Mac- 

 Ginitie and MacGinitie 1968). Even though the 

 strike occurs under water, it is one of the fastest 

 movements known in the animal kingdom taking 

 4 to 8 ms to complete and traveling at a velocity of 

 1,000 cm/s (Burrows 1969). Basically, any animal 

 of appropriate size may fall prey to a stomatopod 

 including fish, shrimp, crabs, annelids, clams, 

 mussels, snails, squids, and echinoderms (Pic- 

 cinetti and Manfrin 1970). 



Stomatopod larvae are often met with in great 

 swarms, particularly in tropical waters. The 

 planktonic larval stages constitute a considerable 

 portion of the diet of reef fishes and commercially 

 important pelagic fishes such as the tunas, skip- 

 jack tuna, mackerel, herring, and snapper iSunier 

 1917; Fish 1925; Reintjes and King 1953; Randall 

 1967; Dragovich 1970). 



Squilla cntpusa Say 1818 is found in the western 

 Atlantic Ocean and ranges from Mass'achusetts, 

 U.S.A. to northern South America, including 

 Trinidad. Venezuela, Surinam, and French 

 Guiana (Manning 1969). It is abundant through- 

 out its range, but is especially prevalent in com- 

 mercial shrimp beds, and is believed to be a serious 

 predator of the shrimp Hildebrand (1954) ob- 



'Institute of Oceanography, Old Dominion University, Nor- 

 folk, Va.; present address: Institute of Marine Science, Univer- 

 sity of North Carolina, Morehead City, NC 28.557, 



^Institute of Oceanography, Old Dominion University, Nor- 

 folk, VA 23508. 



Manuscript accepted August 1978 



FISHERY BUl.I.ETI.N VOL. 77, NO 1. 1979 



served that it is the most abundant crustacean in 

 the offshore trawl fishery of the Gulf of Mexico 

 except for Penacus sp. and Ccilli nectes sp, 

 Stomatopods are fished and eaten in most 

 Mediterranean countries, Japan, and the tropical 

 Pacific (Kaestner 1970). 



Like the adult, the larvae of S. cnipusa are 

 rapacious predators. Able to attain a length of 17 

 mm, they can capture zooplankters as large as 

 themselves by using their second maxillipeds 

 (Lebour 1924). Squilla enipiisa larvae not only fill 

 a role as predators, but also as prey. To date very 

 little has been published on the ecology of the 

 larvae nor has the sequence of pelagic stages been 

 established for this species. 



Of the 350 known species of stomatopods. only 1 

 in 10 can be identified with their larvae and only 1 

 has been reared from hatching to metamorphosis. 

 Difficulty in rearing the larvae has forced inves- 

 tigators to base their accounts on reconstructions 

 made from preserved specimens or from holding 

 planktonic larvae through one ecdysis to connect 

 successive stages. The species of stomatopods for 

 which larvae are definitely known by the rearing 

 of late stage larvae through metamorphosis were 

 listed by Provenzano and Manning (1978). 

 Stomatopod species for which larvae are definitely 

 known by the hatching of eggs also are listed by 

 Provenzano and Manning. 



The only description of the developmental se- 

 quence of S. enipusa was made almost 100 yr ago 

 by Brooks (1878) who captured larvaeat Fort Wool 

 near the mouth of the Chesapeake Bay. Because 



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