Fishes of the JV ester ?i North Atlantic 153 



Provisional Key to Western South Atlantic Species of Rcija^'^ 



I a. Distance from origin of first dorsal fin to tip of tail as long as distance from origin 

 of first dorsal to tips of pelvic fins, or longer. 



agassizii Miiller and Henle 1841. 

 Rio de Janeiro. 

 I b. Distance from origin of first dorsal fin to tip of tail considerably shorter than 

 distance from origin of first dorsal to tips of pelvic fins. 



2 a. Lower surface of disc with many conspicuous black dots and streaks marking 

 the mucous pores. 



3 a. Inner part of each pectoral fin marked with one large and conspicuous 

 pale-centered ocellar spot. cyclophora Regan 1903. 



Rio de Janeiro. 

 3 b. Each pectoral not marked with a large ocellar spot, or, if present, in- 

 distinct. 



4 a. Distance from axils of pelvics to rear end of second dorsal fin only 

 about Vs as long as distance from axils of pelvics to rear margins of 

 orbits; distance from origin of first dorsal to tip of tail considerably 

 shorter than that from level of rear margins of orbits to tip of snout; 

 mucous pores on upper surface of anterior part of disc not marked 

 by black dots or streaks. flavirostris Philippi 1892. 



Patagonian-Falkland Islands re- 

 gion, Straits of Magellan, and 

 Chile. 

 4 b. Distance from axils of pelvics to rear end of second dorsal as long 

 as distance from axils of pelvics to rear margins of spiracles, or 

 longer; distance from origin of first dorsal to tip of tail about as long 

 as distance from level of rear margins of orbits to tip of snout; 

 upper surface of anterior part of disc with black spots and streaks, 

 marking mucous pores. 



5a. Tail with three rows of thorns; margins of orbits and scapular 

 regions also with thorns; snout anterior to orbits only about as 

 long as distance between outer margins of orbits. 



castelnaui Ribeiro 1904. 

 Vicinity of Rio de Janeiro. 

 5b. Tail with only one row of thorns; no thorns around orbits or 

 on scapular regions; snout anterior to orbits about 1.5 times as 

 long as distance between outer margins of orbits. 



64. See Ribeiro (Arch. Mus. nac. Rio de J., 14, 1907: 177-179; Fauna brasil., Peixes, 2 [i] Fasc. i, 1923: 33-36) 

 for descriptions and illustrations of Brazilian species and Norman (Discovery Rep., 16, 1937: 12-47) for those of 

 the Patagonian-Falkland Islands region and Straits of Magellan. The Brazihan Skate reported by Ribeiro, first 

 as Kaja erinacea Mitchill (Arch. Mus. Nac. Rio de J., 14, 1907: 176) and subsequently as R. cirrifera Regan 

 (Fauna brasil. Peixes, 2 [i], Fasc. i, 1923: 33), and by Garman (Mem. Harv. Mus. comp. Zool., 36, 1913: 356) 

 as a new species, R. extenia, is a Psammobatis (see Norman, Discovery Rep., 16, 1936: 28). 



