NO. 3538 CHARACID FISHES — ^WEITZMAN 33 



compressed posteriorly. Greatest depth between posterior tip of 

 appressed pectorals and anterior base of dorsal fin. Standard length 

 of largest specimen examined 25.5 mm. Greatest body depth 3.8 

 (3.5-4.0) ; least depth of caudal peduncle 8.0 (7.5-8.5) ; length of caudal 

 peduncle (including both sexes) 5.7 (5.3-6.2); snout tip to origin of 

 dorsal fin 1.8 (1.8-1.9) ; snout tip to origin of anal 1.3 (1.2-1.3). 



Head and snout obtuse in vertical and horizontal profiles, top of 

 head convex between eyes. Head 3.4 (3.2-3.6) ; eye in head 2.8 (2.7- 

 2.9); snout in eye 1.3 (1.3-1.4); least -width of bony interorbital in 

 greatest eye diameter 1.0 (1.0-1.1). 



Premaxillary with 6 to 7 teeth, each quinque- to tricuspid, sometimes 

 most anterior tooth with only 4 cusps ; lateral cusps largest. In large 

 specimens, largest cusp just medial to lateralmost cusp; cusps subequal 

 in some specimens. Only 1 specimen, SU 50219 from Brazil, wdth any 

 maxillary teeth; this specimen with 1 conical tooth on 1 side only. 

 Dentary with 7 to 8 quinque- or sexcuspid teeth in first outer row. 

 Most posterior tooth in dentary conical, bicuspid, or tricuspid. Speci- 

 mens from Brazil (except specimens from Obidos) having dentary with 

 quinquecuspid teeth, central cusp being largest. Specimens from 

 British Guiana with lower jaw teeth having either 6 subequal cusps or 



5 cusps with a large central cusp. Smallest Brazihan specimen with 

 lower jaw teeth having almost subequal cusps, while some of largest 

 specimens from British Guiana mth very large central cusps on 

 quinquecuspid teeth. Specimens from Obidos wdth 6 subequal cusps 

 on lower jaw teeth and 5 subequal cusps on upper jaw teeth. Teeth 



6 to 7 in second tooth row of dentary. Gill rakers 7 + 12 in all ahzarin 

 preparations. 



Dorsal fin rays ii,8; anal iii,9; pectoral i,10 to i,13; pelvics ii,7. 

 Adipose fin absent in all specimens examined. Caudal fin with princi- 

 pal rays 10/9; distal tips of all ray elements of first 10 principal rays in 

 upper caudal lobe. Lower caudal lobe containing all elements of 

 remaining 9 principal rays. 



Anal fin of male and female alike. Rays of male's anal fin not 

 modified. IncHnator muscle appears slightly, if at all, more developed 

 in male than in female. 



Radial grooves of scales in third horizontal scale series lying below 

 dorsal fin showTi in figiu-e 8. Posterior field mth 1 to 3 radial grooves. 

 Dorsal and ventral fields each with 1 radial groove and anterior field 

 with 2 to 4 radial grooves. Scales 21 to 23 in lateral series in all 

 specimens examined and 3 to 5 lateral-line scales (usually 4); 10 scales 

 in median predorsal series. Total number of vertebrae 31 to 33. Of 

 35 specimens from localities in Brazil, 32 mth 32 vertebrae, 2 with 31 

 vertebrae and 1 wdth 33 vertebrae. Of 15 specimens from localities 

 in British Guiana 9 specimens wdth 31 vertebrae, 1 wdth 33 vertebrae 



219-936 — 66-^3 



