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PROCEEDINGS OF THE NATIONAL MUSEUM 



Description. — ^(See table 1 for measurements.) For explanation 

 of descriptive pattern below, see p. 117. SU 55939 is given first, 

 USNM 196170 follows in brackets. Measurements of SM 5349 are 

 not given because the head is badly damaged, making accurate 

 measurements impossible. 



Figure 5. — Corydoras semiaquilus, new species, holotype, SU 55939. Standard length 



60.9 mm. 



Body relatively elongate, greatest body depth 3.0 (33.5%) [3.0 

 (33.5%)]. Least depth of caudal peduncle 8.9 (11.2%) [8.6 (11.7%)]. 

 Dorsal fin origin nearer snout tij) than caudal fin base. Distance 

 between snout tip and dorsal fin origin 2.0 (50.7%) [2.1 (48.2%)]. 

 Distance between snout tip and anus 1.9 (52.8%) [1.9 (52.5%)]. 

 Anal fin origin to snout tip 1.2 (81.5%) [1.2 (80.4%o)]. Lateral 

 scutes 24/21 [26/23]. Abdomen entirely covered with small to moder- 

 ate-sized imbricated bony plates. Azygous middorsal scutes 7 [6] 

 anterior to adipose fin and 1 [1] anterior to dorsal fin. Pectoral fin 

 base incompletely surrounded by coracoid. Distance between 

 coracoids 8.5 (11.8%) [9.0 (11.2%o)]- Head length 3.0 (32.9%) 

 [3.0 (33.2%)]; greatest head width 1.5 (65.5%) [1.5 (64.8%)] in its 

 length. Least width of bony interorbital 4.1 (24.6%) [3.9 (25.5%)] in 

 head length. Snout acute in dorsal view but snout tip rather broadly 

 rounded. Snout 1.4 (69.5%) [1.4 (69.5%o)] in head length. Dorsal 

 profile of snout concave in both specimens. When directed posteri- 

 orly, both rictal barbels reach a point on a vertical line passed down 

 from posterior eye margin. Greatest diameter of orbit 4.4 (22.5%) 

 [4.4 (22.9%o)] in head length. Greatest width of suborbital 2.8 (35.6%) 

 [1.8 (55.5%)] in orbit. 



