A new species of Moenkhausia Eigenmann, 1903 (Characiformes: Characidae) from Amazon basin, Brazil

Abstract

A new species of Moenkhausia is described from tributaries of the lower Amazon basin, Pará State, Brazil. The new species is morphologically similar to Moenkhausia collettii, M. copei, and M. venerei by the presence of a dark horizontal stripe across the middle portion of the eye, a conspicuous slightly rounded humeral blotch, a dark longitudinal midlateral stripe and a dark stripe along the anal-fin base. However, the new species can be distinguished from M. collettii, M. copei, and M. venerei mainly by the number of cusps on the inner row of the premaxillary, maxillary and dentary teeth, and by the number of scales in transversal series above and below the lateral line.

Moenkhausia andrica (Characiformes: Characidae): a new species from the rio Tapajós basin, Brazil, with minute fin hooklets in females

“…Females of the new species also show minute bony hooklets in all fins as the males. This condition is not encountered elsewhere in Characidae, in which the presence of hooks is more common on the pelvic and anal fins of males (Marinho & Langeani, 2016;Petrolli et al, 2016;Soares & Bührnheim, 2016). The presence of hooks in females is poorly described in the literature, although already Malabarba, 1998;Vera Alcaraz et al, 2009).…”

“…Females of the new species also show minute bony hooklets in all fins as the males. This condition is not encountered elsewhere in Characidae, in which the presence of hooks is more common on the pelvic and anal fins of males (Marinho & Langeani, 2016;Petrolli et al, 2016;Soares & Bührnheim, 2016) Malabarba, 1998;Vera Alcaraz et al, 2009). Vera Alcaraz et al (2009) proposed that masculinization, a natural endocrine variation or even an apomorphic character for the species, could explain this characteristic; nonetheless, the same authors emphasize that detailed studies are necessary to corroborate such hypothesis.…”

“…Females of the new species also show minute bony hooklets in all fins as the males. This condition is not encountered elsewhere in Characidae, in which the presence of hooks is more common on the pelvic and anal fins of males (Marinho & Langeani, 2016; Petrolli et al ., 2016; Soares & Bührnheim, 2016). The presence of hooks in females is poorly described in the literature, although already observed in four characid genera: Astyanax Baird & Girard 1854 (anal fin), Hyphessobrycon Durbin 1908 (pelvic fin), Psalidodon Eigenmann 1908 (pelvic fin) and Cheirodon Girard 1855 (Cheirodontinae) (pelvic fin).…”