PROC. BIOL. SOC. WASH. 95(1), 1982, pp. 188-193 HEMIODOPSIS OCELLATA, A NEW HEMIODONTID CHARACOID FISH (PISCES: CHARACOIDEA) FROM WESTERN SURINAM Richard P. Vari Abstract. — Hemiodopsis ocellata, an open water species occuring in the black water drainages of western Surinam, is described from several localities within the Corantijn River system basin. The pattern of zig-zag lines on the dorsal por-tion of the body appears to be unique in the genus. Introduction The new species described herein, Hemiodopsis ocellata, is widespread in the black waters of the Corantijn River system of western Surinam. Habitats of in-dividuals captured or observed in the wild show that during low water levels this species is primarily an inhabitant of the main river channels and larger open pools and streams rather than the shaded creeks and smaller streams of the rain forest. During high water levels, in contrast, H. ocellata apparently travels up smaller tributaries into the flooded rain forest to feed and reproduce. The species has been taken most often in the more readily sampled still or slowly flowing waters. Nonetheless, the capture of a single specimen in the rapidly-flowing waters of Dalbana Creek and observations over several seasons indicate that H. ocellata also occurs in waters with high flow velocities. This species is usually found in association with the much more abundant Hemiodopsis goeldii, which it closely resembles in overall body form, maximum adult size, and pigmentation pattern (see Bohlke, 1955, fig. 7). Hemiodopsis ocellata, new species Fig. 1, Table 1 Holotype. — National Museum of Natural History (USNM) 221175, 170.0 mm standard length (SL), collected by R. P. Vari, 7 December 1979 in the main stream of Dalbana Creek, approximately 150 m upstream of its junction with the Ka-balebo River, Nickerie District, Surinam (approx. 4°47'N, 57°29'W). Paratypes.—l specimen, USNM 225592, 141.5 mm SL, collected by R. P. Vari and L. R. Parenti, 8 September 1980, in a slow-flowing side channel of the Cor-antijn River about 180 km from its mouth, Nickerie District, Surinam (approx. 5°08'N, 57°18'W); 2 specimens, USNM 225593, 104.7-113.0 mm SL [1 cleared and counterstained for cartilage and bone] coUected by R. P. Vari and L. R. Parenti, 17 September 1980, in a still pool near "Camp Hydro" on an island in the middle of the Corantijn River, Nickerie District, Surinam (approx. 4°22'N, 57°58'W); 4 specimens, USNM 225594, 129.0-142.0 mm SL, coUected by H. M. Madarie, 15 May 1980, in a small creek and the surrounding flooded rain forest of the Corantijn River, Nickerie District, Surinam (approx. 5°32'N, 57°10'W). Diagnosis. — Within the family Hemiodontidae the new species is assignable to
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