Scientists have described two new species of cichlid from the Guianacara genus after they were discovered in the Guiana Shield in eastern Venezuela.
Hernan Lopez-Fernandez, Donald Taphorn and Sven Kullander described the two new cichlids as Guianacara stergiosi and G. cuyunii in the latest issue of ichthyological journal Copeia. Both species are members of the Guianacara subgenus Guianacara - a subgroup categorised by the presence of two supraneurals and the presence of lappets on the dorsal fin spines.
Guianacara stergiosiGuianacara stergiosi was found in the Caroni River and lower Aro River drainages, and from the upper Caura River upstream of the Para rapids. The species can be distinguished from other members of the subgenus by the presence of a round spot in the middle of the flank, which lies below the upper lateral line and forms a dark area in the midlateral bar of the fish.
The authors state that similar markings are also seen in other Guianacara species, but the position of the spot in Guianacara stergiosi is particularly distinctive: "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 cuyuniiThe second new species, Guianacara cuyunii, was discovered in the River Cuyuni drainage in Venezuela and its major tributaries, however, the authors do not yet know whether the distribution of G. cuyunii covers the lower reaches of the Cuyuni and Essequibo River drainages.
G. cuyunii can be told apart from other species in the Guianacara subgenus by its thinner mid-lateral bar. In G. cuyunii, the bar is about three scales wide, whereas in other species it is typically four scales in width. The bar is normally present on all individual, except some very large specimens, where it may be replaced by a mid-lateral spot common in many Guianacara species. It's also the only known Guianacara species with a greyish branchiostegal membrane between the throat and the opercula.
The Guianacara genusThe Guianacara genus was described by Kullander and Nijssen in 1989 and contains four other described species: Guianacara geayi; Guianacara oelemariensis; Guianacara owroewefi and Guianacara sphenozona.
You can view the distributions of Guianacara geayi, Guianacara oelemariensis, Guianacara owroewefi and Guianacara sphenozona on Practical Fishkeeping's Fish Mapper fish distribution mapping application.
For more information see the paper: Lopez-Fernandez H, Taphorn DCB and SO Kullander (2006) - Two New Species of Guianacara from the Guiana Shield of Eastern Venezuela (Perciformes: Cichlidae). Copeia: Vol. 2006, No. 3, pp. 384-395.