WILLIAMS: CRABS OF THE GENUS CALLINECTES 



rectilinear but still sharp tipped. Sub- and outer 

 orbital spines become increasingly acuminate 

 with age. The mesogastric area changes shape 

 with age, the anterior border becoming increas- 

 ingly sinuous and indistinct. Adjacent portions of 

 the mesobranchial regions remain sharply out- 

 lined in old individuals. Some older specimens 

 show "expansion scars" on the carapace as if 

 stresses incurred while molting had stretched 

 the carapace during the hardening process. Such 

 "scars" seem to radiate from centers in the cardiac 

 region. 



The chelae sometimes have lower propodal 

 margins slightly decurved in conjunction with de- 

 velopment of a strong basal tooth on the opposing 

 dactyl. Except for the sharply granulate outer 

 propodal ridge, usually smooth remaining ridges 

 on the chelipeds are occasionally as roughly 

 granulate as in C. exasperatus. 



In sternal view, males have a great resemblance 

 to C. similis in that the abdomen and sternum 

 are nearly plane and that the anterior curvature 

 of fused segments 3-5 is shallow. Males may show 

 a central proximal column of indurated exoskel- 

 eton in the 6th abdominal segment. The first 

 gonopods of mature males may reach beyond the 

 middle of sternite VI to the suture between V 

 and VI. 



Distribution. — San Diego, Calif, to Bahia Al- 

 mejas (southeastern extension of Bahia Mag- 

 dalena) Baja California; La Paz Harbor around 

 Golfo de California to Topolabampo, Sinaloa, Mex- 

 ico (Figure 27). The species is apparently absent 

 from the extreme southern tip of Baja California, 

 but was listed as the commonest large crab in the 

 Golfo de California by Steinbeck and Ricketts 

 (1941). 



Habitat. — Garth and Stephenson (1966) sum- 

 marized the little available ecological data noting 

 that the known depth range is to 18 m, usually 

 over sand bottom, and that many crabs had been 

 captured swimming under lights at night. From 

 museum records it is clear that the species fre- 

 quents estuarine areas. A few specimens from 

 Espiritu Santo, Golfo de California (AHF) are cov- 

 ered with a red clay deposit. 



Spawning. — Only one lot taken in September 

 from Scammon Lagoon, Baja Calif, in water 0.6 m 

 deep contained ovigerous females. This is curious 

 in light of the fact that more mature females have 



been collected than males (Tables 1 and 2), but the 

 record is probably biased by times of collection. Of 

 94 lots for which collection date is recorded, the 

 monthly frequency is: January 5, February 11, 

 March 43, April 17, May 3, June 2, August 3, 

 September 2, October 1, November 5, and De- 

 cember 2. Either spawners were beyond depths 

 sampled (unlikely) or early spring is not the main 

 spawning period for this species. 



Economic importance. — No data are available 

 on uses of this crab other than notes above on its 

 availability in fish markets of Mexico City. Thir- 

 teen lots of fragments, mostly parts of fingers, 

 from archeological sites near Municipio Caborca, 

 La Cholla Bay, Sonora, Mexico, are recorded in the 

 USNM as Callinectes (probably C bellicosus) in- 

 dicating pre-Columbian use of the large crabs by 

 peoples of the area. 



Remarks. — Callinectes bellicosus resembles C. 

 similis of the Carolinian province of the Atlantic 

 in that both are restricted in distribution at the 

 northern fringes of the tropical homeland of the 

 genus, but the analogy is a loose one for C. bel- 

 licosus is the more restricted, essentially endemic 

 to the Golfo de California which is a transitional 

 body of water with Panamanian relationships 

 grading from tropical in the south to temperate 

 (but warm in summer) in the north, and the Pacific 

 coast of the Baja California peninsula whose 

 marine climate is transitional between tropical 

 and dominant temperate from Punta Entrada 

 (Bahia Magdalena) to Point Conception north of 

 Santa Barbara Channel (Garth, 1961a). Temper- 

 ate and tropical faunas meet and mingle along 

 this outer coast, but tropical forms thin out north- 

 ward surviving only in protected shallows. Rec- 

 ords of C. bellicosus are few north of Scammon 

 Lagoon, northern extensions of range being fa- 

 vored by warm periods (Garth, 1961a). The south- 

 ern tip of the peninsula, from which C. bellicosus 

 is absent, is essentially an insular oceanic region 

 distinct from adjacent coastlines and dependent 

 on accidental transport for its marine fauna 

 (Garth, 1961a). 



Belonging to the group of species with moder- 

 ately long first gonopods, C. bellicosus has di- 

 verged from the remainder of the group in having 

 gonopods with rather straightened sinuosity and 

 possession of prominent sternomesial setae. The 

 form of the body bears some resemblance to C. 

 similis, the distributional western Atlantic 



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