Live specimen of E. altipinnis. © Netto-Ferreira et al.

A new miniature characid genus and species from the rio Curuá at Serra do Cachimbo, Pará state, Brazil. has been described in the open access journal PLoS ONE.

Erythrocharax altipinnis is the only known member of the new genus and can be told apart from related groupings by having the pelvic bones firmly attached through the horizontal isquiatic processes.

The new genus and species can be further distinguished from other characid genera by possessing an almost triangular hiatus in the musculature covering the anterior chamber of the swim bladder between the first and second pleural ribs; teeth pedunculate, expanded and distally compressed in both jaws; circumorbital series comprising antorbital and four infraorbital bones with laterosensory canals not enclosed; a single tooth row in the premaxillary with the teeth aligned with each other and similar in shape and cusp number; first three branched dorsal-fin rays elongate in males; adipose and caudal fins bright red in life; a dark midlateral stripe extending from the opercle to the tip of the median caudal-fin rays; no humeral spot.

Type locality of the species in the rio Curuá drainage, Brazil. © Netto-Ferreira et al.

The genus name is taken from the  Greek erythrus, meaning red, in reference to the bright red adipose and caudal fins in live specimens, plus the suffix -charax, as commonly used for Characidae genera.

The specific name is dervived from the Latin alti, meaning elongate, and pinnis, meaning fin, in reference to the extended anterior dorsal-fin rays in males.

It’s currently known only from the type locality, the rio Curuá, a tributary within the larger rio Iriri system which is itself an affluent of the rio Xingu in Amazonian Brazil.

For further information please refer to the full, open access paper: Netto-Ferreira, A. L., J. L. O. Birindelli, L. M. de Sousa, T. C. Mariguela and C. Oliveira. 2013. A New Miniature Characid (Ostariophysi: Characiformes: Characidae), with Phylogenetic Position Inferred from Morphological and Molecular Data. PLoS ONE 8(1): e52098