NO. 3538 CPIARACID FISHES — WEITZMAN 13 



Nannostomus minimus Eigenmann, 1909, p. 42 (original description; type locality: 

 Erukin, British Guiana; holotype in Chicago Natural History Museum); 

 1910, p. 427 (hsted); 1912, p. 282, pi. 36, fig. 5 (description). 



Nannostomus simplex Eigenmann, 1909, p. 42 (original description; type locality: 

 Lama Stop-Off, British Guiana; holotype in Chicago Natural History 

 Museum); 1910, p. 427 (listed); 1912, p. 283, pi. 36, fig. 6 (description). 



Nannostomus beckfordii. — Eigenmann, 1910, p. 427 (Hsted, name emended). 



Nannostomus beckfordi surinami Hoedeman, 1954a, p. 84 (original description; 

 type locality: Berg en Dal at Surinam River, Surinam; holotype in Zoological 

 Museum of Amsterdam). 



Nannosto7nus aripirangensis Meinken, 1931, p. 553 (original description; figure; 

 type locality: Brazil, State of Pard, Aripiranga Island NE. of Bel^m do Pard; 

 types destroyed during World War II, Meinken in litt.). — Axelrod and Schultz, 

 1955, p. 240 (copied description and aquarium notes). — Sterba and Tucker, 

 1962, p. 210 (description and aquarium notes). 



Nannostomus beckfordi aripirangensis. — Hoedeman, 1950, p. 18 (copied descrip- 

 tion) ; 1954a, p. 84 (listed). 



Nannostomus beckfordi anomalus. — Sterba and Tucker, 1962, p. 210 (description 

 and aquarium notes) . 



Diagnosis. — This species possesses few characters not found in 

 at least some of the other members of the genus Nannostomus and is 

 therefore difficult to diagnose by any single characteristic. Perhaps 

 the best single diagnostic character complex is the pattern of horizontal 

 stripes. 



Secondary and tertiary horizontal stripes absent; weU-developed 

 primary horizontal stripe present; few (2-6) perforated lateral line 

 scales present; 9 to 10+17 to 18 gill rakers; iii,9 anal fin rays; and 23 

 to 26 scales in a lateral series. 



Description. — Body slender, cylindrical except in region of 

 moderately compressed caudal peduncle. Greatest body depth 

 slightly anterior to dorsal fin origin. Standard length of largest 

 specimen 29.6 mm. Greatest body depth 4.3 [3.5 in egg-filled females] 

 to 5.0 [in apparently starving specimens]; least depth of caudal 

 peduncle 9.9 (8.8-10.8); length of caudal peduncle of population 

 sample from Obidos (CM 19648) 5.2 (4.9-5.6), of population from 

 Uruard Brook (SU 50257) 6.0 (5.5-6.3); length of caudal peduncle 

 of all specimens measured 5.8 [a rather meaningless figure since the 

 measurements are biased toward a large number of specimens from 

 Uruard Brook, SU 50257] (4.9-6.3) ; snout tip to origin of dorsal fin 

 1.85 (1.62-1.99); snout tip to origin of anal fin 1.30 (1.24-1.35). 



Head conic; snout blunt, obtuse in vertical and horizontal profile. 

 Head 3.8 (3.5-4.0); eye in head 2.8 (2.5-3.2); snout in eye 1.24 

 (1.05-1.39) ; least width of bony interorbit in greatest eye diameter 1.1 

 (1.04-1.19). 



Premaxillary with 6 teeth; anterior teeth quinquecuspid, lateral 

 teeth quinque- to septemcuspid. [There is some geographical varia- 

 tion in the prominence of the individual cusps; for example specimens 



