Two new species of Guianacara from the Guiana Shield of eastern Venezuela (Perciformes: Cichlidae)

We describe two new species of Guianacara from the Guiana Shield of eastern Venezuela. Guianacara stergiosi, new species and G. cuyunii, new species belong in the subgenus Guianacara and thus are distinguished from G. oelemariensis (subgenus Oelemaria) by the possession of two (vs. one) supraneurals and produced lappets on the dorsal-fin spines. Guianacara stergiosi can be distinguished from all other species in the subgenus Guianacara by the possession of a round midlateral spot almost entirely below the upper lateral line, forming the darkest area in the midlateral bar. In other species with a midlateral spot, the spot is oval-shaped and located on and above the upper lateral line (G. sphenozona), or on and below the upper lateral line (G. owroewefi). In Guianacara stergiosi the midlateral bar progressively fades into a midlateral spot in all but small juvenile specimens, distinguishing the species from G. geayi, which generally has a complete midlateral bar; in G. geayi the midlateral bar can be reduced to a midlateral spot in large specimens, in which case the black coloration of the anterior dorsal-fin lappets is lost, whereas it is maintained in G. stergiosi at all sizes. Guianacara stergiosi is known from the Caroni and lower Aro River drainages, and from the upper Caura River basin upstream of the Para rapids. Guianacara cuyunii is distinguished from all other species in the subgenus by the possession of a thinner midlateral bar (about three scales wide vs. four scales wide) that is generally not replaced by a midlateral spot, except in very large specimens, by having a pectoral fin that does not reach the anal fin, and for being the only known species without a grayish branchiostegal membrane. Guianacara cuyunii is known from the upper Cuyuni River drainage in Venezuela, including its major tributaries. It is currently unknown whether the distribution of this species spans the lower reaches of the Cuyuni and Essequibo drainages.