THE ROCK SHRIMP GENUS SICYONIA 

 (CRUSTACEA: DECAPODA: PENAEOIDEA) IN THE EASTERN PACIFIC 



Isabel Perez Farfante^ 



ABSTRACT 



The genus Sicyonia is redefined and the 12 species occurring between Monterey Bay, California, and off 

 Pisco, Peru, are treated in detail. A key to species is followed by illustrated species accounts including 

 descriptions, ranges of intraspecific variation with analyses of morphometric data (rostrum to carapace 

 ratio graphically represented for 10 species), and color notes. The size ranges at which males and the 

 minimum sizes at which females attain adulthood are summarized, and ecological notes together with 

 maps illustrating the ranges of the species (six of which have been extended beyond limits previously 

 reported) are included. Sicyonia disparri seems to be restricted to the south and gulf coasts of Baja 

 California and waters off Nayarit, Mexico; S. affinis to waters off Costa Rica, Panama, and Colombia; 

 and S. penicillata occurs on the ocean side of Baja California Sur, Mexico, and from the Gulf of 

 California to Costa Rica. Sicyonia ingentis ranges from Monterey Bay to Nayarit, including the Gulf of 

 California. Sicyonia disedwardsi and S. martini occur along the ocean side of Baja California Sur, in 

 the Gulf of California, and southward to Panama, and four others, S. aliaffinis,S. disdorsalis,S. mixta, 

 and S. picta, frequent the same waters, but also reach as far south as Peru. Sicyonia laevigata and S. 

 brevirostris are found on both sides of the Continent, the former at the southern end of the Gulf of 

 California and from off Costa Rica to the Golfo de Panama in the Pacific, and from North Carolina to 

 Santa Catarina, Brazil, in the Atlantic. Sicyonia brevirostris has been recorded from the Golfo de 

 Tehuantepec and from Virginia southward through the Gulf of Mexico to Yucatan, and also from the 

 Bahamas and Cuba. In addition, there is an unverified literature record from Guyana. The treatment of 

 each species is concluded with a comparison of its diagnostic features with those of the most closely 

 allied congeners and a note on its present or potential economic value. 



Until a few years ago, members of the genus 

 Sicyonia, "rock shrimps", were discarded from the 

 large commercial catches of panaeoid shrimps 

 made in tropical and subtropical waters of the 

 eastern Pacific and western Atlantic. It was com- 

 monly thought that because of their hard, stony 

 exoskeleton, they would be rejected by both con- 

 sumers and the processing industry; however, in- 

 creased demand for shrimp encouraged the 

 fishermen and dealers to bring the larger species 

 to market, and now production is not only readily 

 absorbed, but some prefer rock shrimps to the 

 thinner shelled species. 



The exploitation and comparatively recent rec- 

 ognition of the commercial potential of Sicyonia, 

 the most distinctive group within the superfamily 

 Penaeoidea, have motivated this review of mem- 

 bers of the genus found in the American Pacific 

 (the western Atlantic species have already been 

 the object of a number of studies, e.g., Chace 1972; 

 Huff and Cobb 1979). For the most part, the infor- 



Systematics Laboratory, National Marine Fisheries Service, 

 NOAA, National Museum of Natural History, Washington, DC 

 20560. 



mation available is limited to the original descrip- 

 tions of the species, which are scattered in works 

 published between 1871 and 1945, and to a limited 

 number of locality records. Of the 12 species occur- 

 ring in the region, 4 had been recognized prior to 

 the close of the century. No other species were 

 reported from these waters until Burkenroad 

 made his invaluable studies (1934-45) which re- 

 sulted in the recognition of five new species plus 

 two others previously known to occur only in the 

 western Atlantic. Recently, Perez Farfante and 

 Boothe (1981) described the 12th member of the 

 genus frequenting the eastern Pacific. Two works 

 have been helpful in the identification of the 

 American Sicyonia: one by Anderson and Lindner 

 (1945) which provided a key to the then known 

 species; the other by Arana Espina and Mendez G. 

 (1978) in which was presented an illustrated key, 

 diagnoses, and ranges of the species found in 

 Peruvian and Ecuadorean waters, and an analysis 

 of morphometric relations, with data on the 

 growth and molting pattern of one of the species. 

 The extensive collections (515 lots containing 

 4,672 specimens) of Sicyonia available from Mon- 

 terey Bay, Calif., to off Pisco, Peru, and the oppor- 



Manuscript accepted April 1984. 



FISHERY BULLETIN: VOL. 83, NO. 1, 1985. 



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