THE SWIMMING CRABS OF THE GENUS CALLINECTES 



(DECAPODA: PORTUNIDAE) 



Austin B. Williams^ 



ABSTRACT 



The genus Callinectes and its 14 species are reevaluated. Keys to identification, descriptions of species, 

 ranges of variation for selected characters, larval distribution, and the fossil record as well as problems 

 in identification are discussed. Confined almost exclusively to shallow coastal waters, the genus has 

 apparently radiated both northward and southward from a center in the Atlantic Neotropical coastal 

 region as well as into the eastern tropical Pacific through continuous connections prior to elevation of 

 the Panamanian isthmus in the Pliocene epoch and along tropical West Africa. Eleven species occur in 

 the Atlantic, three in the Pacific. Callinectes marginatus spans the eastern and western tropical 

 Atlantic. Callinectes sapidus. with the broadest latitudinal distribution among all the species (Nova 

 Scotia to Argentina), has also been introduced in Europe. All species show close similarity and great 

 individual variation. Both migration and genetic continuity appear to be assisted by transport of 

 larvae in currents. Distributional patterns parallel those of many organisms, especially members of 

 the decapod crustacean genus Penaeus which occupy similar habitats. 



The blue crab, Callinectes sapidus Rathbun, a sta- 

 ple commodity in fisheries of eastern and southern 

 United States, is almost a commonplace object of 

 fisheries and marine biological research, but its 

 taxonomic status has been questionable for a long 

 time. Other members of the genus also have ques- 

 tionable taxonomic status, and they are difficult to 

 identify. In a time when expanding interest in 

 species easily exploitable for food has generated 

 new research, we can benefit from a fresh look at 

 the component species of this important genus in 

 order that major areas of study such as fisheries 

 biology, ecology, zoogeography, embryology, and 

 physiology can proceed on a stable nomenclatural 

 basis. The purposes of this paper are to: 11 

 synonymize nomenclature, 2) characterize the 

 species, 3) discuss variation in morphology, 4) 

 provide illustrations and keys to identification, 5) 

 delineate geographic distribution of species, 6) 

 provide remarks on ecological associations, 7) con- 

 tribute to resolution of the fossil record, and 8) 

 document evidence and provide a list of identified 

 specimens in major museums of the world. 



HISTORY 



Crabs of the genus Callinectes have an anec- 

 dotal record dating from early explorations of the 

 Western Hemisphere. Perhaps the earliest listing 

 among natural assets in the New World is Thomas 

 Hariot's (1588) mention of "Sea crabbes, such as 



'Systematics Laboratory, National Marine Fisheries Service, 

 NOAA, U.S. National Museum, Washington, DC 20560. 



we have in England." A similar record is 

 Marcgrave's account in 1648 (Lemos de Castro, 

 1962) of a South American Callinectes [= danae 

 Smith (1869)], one of the common portunids used 

 for food. D. P. de Vries in 1655 (Holthuis, 1958) 

 referred to the eating qualities of blue crabs in the 

 New York area and likened the white and orange 

 color of their chelipeds [females] to colors of the 

 House of Orange. Lawson (1714), recounting his 

 years among the Indians in the Carolinas, may 

 have initiated the tale of raccoons fishing for crabs 

 in marshes with their tails, but more factually he 

 wrote [undoubtedly of the blue crab, C sapidus 

 Rathbun (1896)], "the smaller flat Crabs I look 

 upon to be the sweetest of all Species . . . the 

 Breadth of a lusty Man's Hand .... These are 

 inumerable, all over the salts of Carolina . . . 

 taken not only to eat, but are the best Bait for all 

 sorts of Fish, that live in the Salt-Water." 



Holthuis (1959) thought that de Geer (1778) 

 probably represented Callinectes bocourti A. 

 Milne Edwards (1879) under the name "Crab de 

 I'ocean" when he described a swimming crab from 

 Surinam in general terms as Cancer pelagicus. 

 Ordway (1863) considered de Geer's species 

 synonymous with Lupa sayi Gibbes (1850), and 

 Rathbun (1896:350) stated "Figures 8, 9 and 11 

 correctly represent neither of these species, nor 

 are they applicable to any species of Callinectes, 

 while, on the other hand, Figure 10 shows the 

 narrow abdomen characteristic of that genus." 

 Since C. bocourti is the commonest portunid in 

 Surinam, abundant enough to be marketed, and 



Manuscript accepted December 1973. 

 FISHERY BULLETIN: VOL. 72, NO. 3, 1974. 



685 



