12 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii9 



The color pattern of Nannostomus espei greatly resembles that of 

 Pyrrhulina vittata Regan and Pyrrhulina spilota Weitzman. Many of 

 the scales of Nannostomus espei are more like those in the genera 

 Pyrrhulina, Copeina, and Copella than those of other species of 

 Nannostomus or Poecilobrycon. In figure 1, the scale to the left is 

 from the third longitudinal scale row, just below the dorsal fin. It is 

 typically pyrrhulininan in outline. That to the right is from the 

 second longitudinal row near the adipose fin and is typically nan- 

 nostominan in outline. The phylogenetic significance of these facts 

 is not understood, especially since this species has the typical osteology 

 of Nannostomus. It seems possible that this species has retained a few 

 primitive features that were present in its presumably somewhat more 

 Pyrrhulina-like ancestors. This species also has a body form which 

 suggests that of the subtribe Pyrrhidinina more than the body form 

 of any other species of Nannostomus or Poecilobrycon. The body form 

 of Nannostomus and Poecilobrycon is usually more or less smoothly 

 fusiform, whereas that of Pyrrhulina is not, the profde showmg a 

 slight notch behind the dorsal fin and the belly being slightly flat. 

 Nannostomus espei has the dorsal notch of Pyrrhulina. This body 

 shape in espei is subtle and considerable experience with live and 

 preserved specimens was necessary before it was detected. 



Specimens examined. — Five (one alizarin preparation), ANSP 73873, SL 21.5- 

 28.1 mm., British Guiana, an unnamed creek, tributary to the Paruma River, a 

 tributary of the Mazaruni River via the Kamarang River, Pakaraima Mountain 

 region of western British Guiana, lat. 5°50'-55' N., long. 61°05'-10' W., 1955, 

 Louis Chung. — One alizarin preparation, SU 50252, SL 25.0 mm., aquarium speci- 

 mens, locahty unknown but probably British Guiana. — Seven, SU 50214, SL 25.5- 

 27.0 mm., aquarium specimens, locahty unknown but probably British Guiana. — 

 One, SU 51593 (lectotype) and two, SU 51592, paralectotypes, for locahty see 

 discussion on page 11. 



Nannostomus beckfordi Giinther 



Figures 2, 3, 4 



Nannostomus beckfordi Giinther, 1872, p. 146 (original description; type locality: 

 Goedverwating, a plantation on the coast of Demerara, British Guiana; 

 holotype in British Museum [Natural History]). — Eigenmann and Eigen- 

 mann, 1891, p. 49 (listed). — Eigenmann, 1912, p. 281 (copied description). — 

 Hoedeman, 1950, p. 16 (description; no specimens listed). — Boeseman, 1954, 

 p. 18 (Surinam). 



Nannostomus anomalus Steindachner, 1876, p. 129 (original description; type 

 locality: mouth of Rio Negro, Brazil; types in Vienna Museum). — Eigenmann 

 and Eigenmann, 1891, p. 49 (listed). — Eigenmann, 1910, p. 427 (listed). — 

 Meinken, 1931, p. 554 (description from life; figure). — Innes, 1935 and later 

 editions, p. 153 (description from life; photograph). — Puyo, 1949, p. 117 

 (description; Cayenne Island, French Guiana). — Boeseman, 1952, p. 184 

 (Surinam); 1953, p. 16 (Surinam). — Axelrod and Schultz, 1955, p. 239 

 (description and aquarium notes). 



