THE MEGALOPA STAGE OF THE GULF STONE CRAB, MENIPPE ADINA 

 WILLIAMS AND FELDER, 1986, WITH A COMPARISON OF MEGALOPAE 



IN THE GENUS MENIPPE 



Joel W. Martin,' Frank M. Truesdale,^ and Darryl L. Felder^ 



ABSTRACT 



The laboratory-reared megalopa stage of the Gulf stone crab, Menippe adina , is described and illus- 

 trated and compared with megalopae of three other species of Menippe . The megalopa of M . adina 

 differs from that of Af. nodifrons in having serrate spines on the ventral margin of the dactylus of 

 pereiopod 5 and from that of M. rumphii in having spines on the dactyli of pereiopods 2-5 and a more 

 quadrate carapace. The megalopa of the morphologically similar A/ . mercenaria was also reared in the 

 laboratory, and selected characters are described and compared with the megalopa of A/, adina; 

 megalopae of the two species differ only slightly. Megalopae of M. adina taken from field collections 

 made off South Texas, U.S.A., were compared with and were found to be consistent with laboratory- 

 reared M . adina megalopae. 



Stone crabs of the genus Menippe are large xan- 

 thid crabs common along the eastern coasts of the 

 United States and Mexico from North Carolina to 

 Yucatan, the Bahamas, Cuba, and Jamaica 

 (Rathbun 1930; Felder 1973; Williams 1984; 

 Williams and Felder 1986). Recently the 

 "common" stone crab, Menippe mercenaria (Say, 

 1818), was divided into two species: Menippe mer- 

 cenaria (Say) (restricted), known from the east 

 coast of the United States, the Caribbean, and the 

 west coasts of Florida and Yucatan, and Menippe 

 adina Williams and Felder, 1986, known from the 

 northwestern Gulf of Mexico; hybridization of the 

 two species occurs in northwest Florida (see 

 Williams and Felder 1986). These two species 

 (primarily M. mercenaria ) support an important 

 stone crab fishery in the southern United States 

 and Mexico (Williams and Felder 1986) and con- 

 sequently have been the subject of numerous in- 

 vestigations. Despite this interest, the complete 

 larval developments of both commercial species of 

 Menippe remain unknown. For M. mercenaria 

 (Say), Hyman (1925) described a prezoea and first 

 zoeal stage, and Porter (1960) described six zoeal 

 stages reared in the laboratory. Unfortunately, 

 Porter did not describe the megalopa stage, pre- 



iLife Sciences Division, Natural History Museum of Los An- 

 geles County, 900 Exposition Boulevard, Los Angeles, CA 

 90007. 



2School of Forestry, Wildlife, and Fisheries, and Louisiana 

 Agricultural Experiment Station, Louisiana State University, 

 Baton Rouge, LA 70803. 



3Department of Biology and Center for Crustacean Research, 

 University of Southwestern Louisiana, Lafayette, LA 70504. 



sumably because he considered it a postlarva and 

 not a true larval stage. An unpublished but often- 

 cited report by Kurata"* included descriptions of 

 the zoeal stages of M. mercenaria and a brief 

 sketch of the megalopa; Kurata's description of 

 the megalopa did not include morphology of the 

 pleopods, pereiopods, or mouthparts. 



Because of recent interest in the phylogenetic 

 significance of the brachyuran megalopa (see Rice 

 1981a, in press; Martin in press) and postlarval 

 stages (Martin et al. 1984; Felder et al. 1985), and 

 because of the potential importance of stone crab 

 larval biology to aquaculture, it is surprising that 

 the megalopae of M . mercenaria and M . adina 

 remain undescribed. The present paper describes 

 the laboratory-reared megalopa of the Gulf stone 

 crab, Menippe adina Williams and Felder, and 

 compares it with field collections of the same spe- 

 cies from south Texas, laboratory-reared megalo- 

 pae of M. mercenaria, and all previously de- 

 scribed megalopae of the genus Menippe: Menippe 

 mercenaria (Say, 1818) (as described by Kurata 

 fn. 4); Menippe nodifrons Stimpson, 1859 (as de- 

 scribed by Scotto 1979); and Menippe rumphii 

 (Fabricious, 1798) (as described by Kakati 1977). 



MATERIALS AND METHODS 



A large ovigerous M . adina was collected from 



Manuscript accepted February 1988. 

 FISHERY BULLETIN: VOL. 86, NO. 2, 1988. 



4Kurata, H. 1970. Studies on the life histories of decapod 

 Crustacea of Georgia. Part IIL Larvae of decapod Crustacea of 

 Georgia. Unpubl. rep., 274 p. University of Georgia Marine 

 Institute, Sapelo Island, GA. 



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