.' ■ - 185 



the sides of the body. Swimbladder large, not encased in bony capsule. 

 Branchiostegal rays 8-9, modally 9 ^geneiosus pardalis. 



9b. Found only in the Rio Parand-Paraguay and Rio Uruguay basins of southern 

 Brazil, Paraguay, Uruguay, and Argentina. Pigmentation typically mottled on 

 head and top of back, but rarely on sides of body below lateral line. 

 Swimbladder small, encapsulated by bone. Branchiostegal rays 9-11, modally 10 A 

 geneiosus valendennesi. 



10a (5b). Maximum adult body size greater than 50 mm SL. Pigmentation variable, 

 but generally either with some evidence of discrete black or brown spots or 

 blotches on the head, chin, and/or sides of the body. Swimbladder with two 

 posterior caecae. Branchiostegal rays 7-10, modally 8 or 9 11. 



10b. Maximum adult body size less than 50 mm SL. Pigmentation consisting of 

 numerous small, diffuse brown specks on top of head and sides of body. A dark 

 brown, hourglass-shaped band of pigment at base of caudal fin. Swimbladder 

 without posterior caecae. Branchiostegal rays 7-8, modally 7. Presently known 

 only from specimens collected in Clearwater rivers draining the Guiana Shield 

 ^geneiosus piperatus. 



11a (10a), Body typically with many small, discrete brown or black spots distributed 

 on top of the head, along the back, and on the sides (some specimens, however, 

 are nearly immaculate or have only a light brown cast on the dorsum). Occipital 

 region of head angled sharply upward to dorsal fin origin. Postcleithral process 

 usually present, but very small or absent in some specimens. Anal-fin length 

 variable but relatively long, with 29-42 rays. Preanal vertebrae 13-16. Paired 



