THE ROCK SHRIMP GENUS SICYONIA (CRUSTACEA: DECAPODA: PENAEOIDEA) IN THE EASTERN PACIFIC ISABEL PEREZ FARFANTE 1 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 ofintraspecific variation with analyses ofmorphometric 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 ofthe species (six ofwhich 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 offCosta 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 Gulfof California. Sicyonia disedwardsi and S. martini occur along the ocean side of Baja California Sur, in the GulfofCalifornia, 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 Gulfof Mexico to Yucatan, and also from the Bahamas and Cuba. In addition, there is an unverified literature record from Guyana. The treatmentof 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 mation available is limited to the original descrip­ Sicyonia, "rock shrimps", were discarded from the tions of the species, which are scattered in works large commercial catches of panaeoid shrimps published between 1871 and 1945, and to a limited made in tropical and subtropical waters of the number oflocality records. Ofthe 12 species occur­ eastern Pacific and western Atlantic. It was com­ ring in the region, 4 had been recognized prior to monly thought that because of their hard, stony the close of the century. No other species were exoskeleton, they would be rejected by both con­ reported from these waters until Burkenroad sumers and the processing industry; however, in­ made his invaluable studies (1934-45) which re­ creased demand for shrimp encouraged the sulted in the recognition of five new species plus fishermen and dealers to bring the larger species two others previously known to occur only in the to market, and now production is not only readily western Atlantic. Recently, Perez Farfante and absorbed, but some prefer rock shrimps to the Boothe (1981) described the 12th member of the thinner shelled species. genus frequenting the eastern Pacific. Two works The exploitation and comparatively recent rec­ have been helpful in the identification of the ognition of the commercial potential of Sicyonia, American Sicyonia: one by Anderson and Lindner the most distinctive group within the superfamily (1945) which provided a key to the then known Penaeoidea, have motivated this review of mem­ species; the other by Arana Espina and Mendez G. bers of the genus found in the American Pacific (1978) in which was presented an illustrated key, (the western Atlantic species have already been diagnoses, and ranges of the species found in the object ofa number ofstudies, e.g., Chace 1972; Peruvian and Ecuadorean waters, and an analysis Huff and Cobb 1979). For the most part, the infor- of morphometric relations, with data on the growth and molting pattern of one ofthe species. The extensive collections (515 lots containing 'Systematics Laboratory, National Marine Fisheries Service, . NOAA, National Museum of Natural History, Washington, DC 4,672 specimens) of Sicyonia available from Mon­ 20560. terey Bay, Calif., to offPisco, Peru, and the oppor- Manuscript accepted April 1984. 1 FISHERY BULLETIN: VOL. 83, NO.1, 1985. FISHERY BULLETIN: VOL. 83, NO.1 tunity to examine all except two of the extant extension within the limits cited herein, and all of type-specimens ofthe species have made a critical the gaps encompass areas off southern Mexico. study of the genus in the eastern Pacific possible. Perhaps the discontinuities are due to limited The present work includes a definitionofthe genus exploratory investigations; however, one species, and a key to the species occurring in the region. A S. disdorsalis, has been found to occur virtually complete synonymy and usually complete list of continuously from the Gulf of California to Peru. references, vernacular names, and a diagnosis Nevertheless, speculations attempting to explain precede the detailed description of each species, the apparent gaps in the ranges of these species which includes a discussion ofthe extensive varia­ should await the confirmation of their existence. tion exhibited as well as meristic and morphomet­ Exceptfor records ofthe occurrence ofS. picta at ric data. In addition, relation of the length of the 333 m (Faxon 1893) and 369-400 m (Arana Espina rostrum to the length of the carapace is graphed and Mendez G. 1978) and S. brevirostris at 329 m for 10 species. Color notes, size range at which (Williams 1965), no other species were previously males reach adulthood, and minimum size known from depths greaterthan about200 m; here at which females have been observed to be im­ six others are reported between about 250 and 300 pregnated are given. Geographic and bathymetric m, depths considerably greater than their previ­ ranges are delimited, and ecological data are pro­ ously known maximum occurrence. vided. Analyses ofthe diagnostic features utilized Distributions ofmembers ofthe genus Sicyonia in the recognition of species and a discussion of in the eastern Pacific appear to differ strikingly their phylogenetic relationships are also pre­ from those of most species of the closely related sented. Distributional maps as well as illustra­ family Penaeidae in that region. Whereas some tions of entire animals, genitalia, and a few other species ofSicyonia are restricted to comparatively morphological features are included along with a small areas (one confined to the southern and gulf bibliography which is as complete as possible. A coasts ofBaja California and waters immediately statement of their economic importance follows south), others range from the GulfofCalifornia to the treatment ofthe pertinent species, and a list of the northern or to the central coasts ofPeru. Most the specimens examined, with their localities, is of the eastern Pacific species, like their western appended to each ofthe 12 species. Atlantic congeners, reveal a markedpreference for The distributional studies have resulted in ex­ firm or coarse bottoms. tensions of both geographic and bathymetric ranges of several species; e.g., ofthe seven species PRESENTATION OF DATA known to occur both in the Gulf of California and on the ocean side of the peninsula, five have not Many characters used in the descriptions are been previously reported from the latter, and one, depicted in Figures 1-7. To provide an appreciation which had been recorded only as far north as Point of the structure of the eye and the nomenclature Conception, Calif., was found to reach Monterey employed in its description I have chosen that ofS. Bay (Perez Farfante and Boothe 1981). Of the 12 disedwardsi. To illustrate the first article of the species thathave been reported from the region, 10 antennular peduncle and anterior gnathal append­ (or 11, in the unlikely event that the presence ofS. ages, S. ingentis was selected. The petasmata affinis is confirmed) occurinthe GulfofCalifornia; have been drawn from specimens stained with fast ofthose occurring in the gulf, S. disparri appears green. For convenience, both the armature of ster­ to be virtually confined to it and only S. ingentis nite XI and the shape of the posterior thoracic extends northward beyond Mexico, along the coast ridge are presented with the description of the ofthe United States. Eight ofthe 10 species range thelycum. Scales accompanying the illustrations southward to Central America, and of them 4 are in millimeters. The length of the rostrum (d) reach as far as Peru and S. aliaffinis also occurs off recorded herein is the linear distance from the Islas Galapagos. Sicyonia brevirostris has been apex to the orbital margin; length ofthe carapace reported exclusively from the Golfo de Tehuan­ (cl) is the distance between the orbital margin and tepec, and S. affinis is known with certainty only the midposterior margin of the carapace; and the from Costa Rica to Colombia. total length (t1) is the distance from the apex ofthe Seven of the species, S. laevigata, S. mixta, S. rostrum to the posterior end of the telson. The disedwardsi, S. penicillata, S. aliaffinis, S. mar­ geographic distribution of each ofthe species pre­ tini, and S. picta, appear to have disjunct ranges. sented onthe maps is basedon material personally None has been recorded from stretches variable in examined and on published records believed to be 2 PEREZ FARFANTE: ROCK SHRIMP GENUS SICYONIA reliable. The names of the countries cited are in Commission on Zoological Nomenclature, Opin­ English as are the Gulfof California and the Gulf ion 382, 1956:45; Hemming1958:126.] Gender: of Mexico; otherwise, all geographic features and feminine. localities are in the language of the country in Ruuulus de Natale 1850:20 (published as synonym which they occur.