210 PROCEEDINGS OF THE NATIONAL MUSEUM vol.04 



KEY TO THE SPECIES OF PIMELODELLA REPORTED FROM VENEZUELA 



la. Upper caudal lobe shorter than lower; length of adipose fin 2.8 in standard 

 length; eye 1.2 in distance from rear base of dorsal to origin of adipose fin; 

 eye 1.25 in interorbital; maxillary barbel extending to end of adipose fin; 

 outer mental barbel nearly to pelvics; inner mental barbel just beyond 

 insertion of i)elvics; first ray of dorsal not quite so long as head; a dark 

 stripe from snout to caudal fin base; dorsal fin hyaline at base, dusky 



distally (Rio Tapa Tapa) Pimelodella tapatapae Eigenmann 



16. Upper caudal lobe longer than the lower. 

 2a. First ray of dorsal fin prolonged into a filament about twice as long as 

 other rays of dorsal and one-third longer than head; head contained in 

 upper caudal lobe 1% times; length of adipose fin 3.2 in standard length; 

 maxillary barbel reaching to tips of pelvics; outer mental barbel reaching 

 to middle of length of pectorals; inner mental barbels reaching to insertion 

 of pectorals; eye contained 2.8 in distance between base of dorsal and 

 origin of anal fin; eye 1.3 in interorbital; anus closer to base of caudal 

 than tip of snout by a distance equal to % of snout; dorsal fin hyaline 

 in basal third, pale dusky distally; a black stripe from snout to base 



of caudal Pimelodella linami, new species 



26. First ray of dorsal fin not extending beyond other rays of that fin, and 

 about same length as head. 

 3o. Maxillary barbel extending to base of caudal fin or farther; upper lobe 

 of caudal fin 2.5 in standard length; length of adipose fin less than 



3 times in length Pimelodella gracilis (Cuvier and Valenciennes) 



36. Maxillary barbel not extending beyond tip of anal fin. 



4a. Basal portion of dorsal fin hyaline, with middle part blackish, fading 

 distally; length of adipose fin contained 3 to 3.25 in standard length. 



Pimelodella metae Eigenmann 



46. Dorsal fin with dark pigment just in front of each ray on interradial 



membrane, anterior half of this membrane hyaline; length of adipose 



fin contained 2.8 to 3.2 times in standard length. 



5a. Maxillary barbels reaching anywhere from middle of anal base to a 



trifle beyond tips of anal fin; outer mental barbel extending to 



opposite tips of pectorals, and inner a httle past base of pectorals; 



dorsal and pectoral spines almost equal in length, rarely is pectoral 



longer Pimelodella chagresi odynea, new subspecies 



5b. Maxillary barbels reaching almost to anal origin, sometimes only to 

 tips of pelvics; outer mental barbels extending almost to middle 

 of length of pectorals, and inner mental barbels reaching only 

 two-thirds way to base of pelvics; pectoral spine a little longer 

 than dorsal spine, rarely equal. 



Pimelodella chagresi chagresi (Steindachner) 



PIMELODELLA TAPATAPAE Eigenmann 



Pimelodella tapatapae Eigenmann, Indiana Univ. Studies, vol. 7, No. 44, p. 5, 

 1920 (mouth of Rfo Tapa Tapa, Valencia Basin). 



PIMELODELLA LINAMI. new specie* 



Plate 1, D 



Holotype.—U.S.NM. No. 121132, the only known specimen, 75.2 

 mm. in standard length, collected by Leonard P. Schultz, March 31, 

 1942, in the Rio Torbes, 1 km. above Tariba, Venezuela, Orinoco 

 system. 



