A new colorful species of Geophagus (Teleostei: Cichlidae), endemic to the rio Aripuanã in the Amazon basin of Brazil

Geophagus mirabilis, new species, is endemic to the rio Aripuanã drainage upstream from Dardanelos/Andorinhas falls. The new species is distinguished from all other species of the genus by the presence of one to five large black spots arranged longitudinally along the middle of the flank, in addition to the black midlateral spot that is characteristic of species in the genus and by a pattern of iridescent spots and lines on the head in living specimens. It is further distinguished from all congeneric species, except G. camopiensis and G. crocatus, by the presence of seven (vs. eight or more) scale rows in the circumpeduncular series below the lateral line (7 in G. crocatus; 7-9 in G. camopiensis). Including the new species, five cichlids and 11 fish species in total are known only from the upper rio Aripuanã, and 15 fish species in total are known only from the rio Aripuanã drainage.