Petitella Géry & Boutière, 1964

Bittencourt, Pedro Senna, Machado, Valéria Nogueira, Marshall, Bruce Gavin, Hrbek, Tomas & Farias, Izeni Pires, 2020, Phylogenetic relationships of the neon tetras Paracheirodon spp. (Characiformes: Characidae: Stethaprioninae), including comments on Petitella georgiae and Hemigrammus bleheri, Neotropical Ichthyology (e 190109) 18 (2), pp. 1-11 : 7

Petitella Géry & Boutière, 1964

Type -species. Petitella georgiae Géry & Boutière, 1964

Diagnosis. The genus Petitella is readily distinguished from all remaining characid genera by the possession of a distinctively bright red head, the presence of a black horizontal bar that extends from the end of the caudal peduncle to the middle rays of the caudal-fin, and the presence of an oblique black bar in each caudal-fin lobe, separated by white colored bands. Contact between frontals anterior to frontal fontanel present; posterodorsal margin of ethmoid cartilage and lateral ethmoids distant from lateral ethmoids; 17 or fewer branched anal-fin rays; only one or two anal-fin hooks on each ray of adult males; the presence of parallel longitudinal ridges on the posterior field of scales; scales covering one-third of the length of caudal-fin lobes; coloration of the head distinctively red, especially the snout.

Petitella bleheri (Géry & Mahnert, 1986) , new combination Hemigrammus bleheri Géry & Mahnert, 1986:41 , fig. unnumb. (original description; type-locality: Middle Rio Negro basin, Brazil, probably near Rio Jufaris).