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[[ Genus Bryconops ]]
The genus Bryconops contains 15 species (Chernoff et al., 1994, 2002; Chernoff and Machado-Allison, 1999; Machado-Allison et al. 1993, 1996; Machado-Allison and Chernoff, 1997), including the two species that are described herein. The genus is widely distributed in the cis-Andean lowlands of South America from the Orinoco to the Paraná- Paraguay basins including many coastal basins of the Guyanas and Brazil. Although B. alburnoides Kner, 1859 , is known to inhabit relatively basic, white-water habitats (e.g., flood plain lakes of the lower Orinoco [ Rodríguez and Lewis, 1990]), most species are found in lotic habitats that are typically acidic and transparent, despite the color of the water. Many species inhabit morichal (aguajal, vereda) habitats that are dominated by the moriche palm ( Mauritia sp.).
The two new species inhabit the Orinoco and Cuyuni watersheds (Fig. 1). The latter occurs on the Guyana Shield above the cataracts in the Essequibo River basin. The two new species belong to the subgenus Bryconops because of the synapomorphies of the jaws and gill rakers that they share (discussed below) with the other members of the subgenus: Bryconops alburnoides , Bryconops caudomaculatus ( Guenther , 1864) , Bryconops disruptus Machado-Allison and Chernoff, 1997 , and Bryconops durbini (Eigenmann 1908) . Within this group the new species superficially resemble B. caudomaculatus , an enigmatic taxon, B. disruptus , and B. durbini because of the colorful ocellus on the dorsal lobe of the caudal fin. Indeed, the new species have been identified as B. caudomaculatus in collections.
In this paper we describe two new species of the genus Bryconops , compare them with other member of the subgenus, and discuss some aspects on the morphometry and shape changes in these species. We comment on the characteristics of B. caudomaculatus in order to clarify its status. Lastly, we provide an artificial key to the species of Bryconops .