FISHERY BULLETIN: VOL. 83, NO. 1 



Figure 37.— Sicyonia affinis, 9 17 mm cl, 4.4 km off Isla Ma- 

 nuelita, Costa Rica. Thelycum. Scale = 1 mm. 



able, larger male 21.5 mm cl, about 46 mm tl; 

 largest female, 17 mm cl, about 62 mm tl. 



Geographic and bathymetric ranges. — Known 

 with certainty only from a restricted area between 

 Isla Manuelita (5°34'N, 87°00'W), Costa Rica, and 

 Isla de Malpelo (3°58'20"N, 81°36'00"W), Colom- 

 bia (Fig. 38). Chirichigno Fonseca (1970) and 

 Arana Espina and Mendez G. (1978) cited Paita, 

 Peru, as the southern limit of the range of the 

 species. Chirichigno Fonseca did not present a list 

 of her material and Matilde Mendez G.^ found no 

 representative of the species in Peruvian collec- 

 tions, including those of the Instituto del Mar del 

 Peru (IMARPE) from which Chirichigno Fonseca 

 obtained most of her information. Chapa Saldaha 

 (1964) recorded the occurrence of this species in 

 the waters of Chiapas and Sinaloa, Mexico, but 

 again, more recent studies, including the present 

 one based on extensive material, failed to disclose 



its presence north of Costa Rica. Further investi- 

 gations are necessary to ascertain the limits of the 

 range of this shrimp both south of Isla de Malpelo 

 and north of Isla Manuelita. Sicyonia affinis is one 

 of only four members of the genus that have been 

 recorded from the eastern Pacific off South 

 America. 



This species has been found at depths between 

 79-77 and 205 m, on substrates of rocks or broken 

 shells. 



Discussion . — Sicyonia affinis is one of the three 

 closely related American Pacific species belonging 

 to Burkenroad's (1934a) "affinis group" of his Divi- 

 sion II. He characterized this group (in which he 

 included S. affinis and S. aliaffinis, and to which 



* S. affinis 



* S. aliaffinis 



* S . martini 



'Matilde Mendez G., Instituto del Mar del Peru, Callao, Peru, 

 pers. commun., January 1984. 



46 



Figure 38. — Geographic distribution of Sicyonia affinis, S. 

 aliaffinis, and S. martini. 



