Larval Development of Boulengerella cuvieri (Characiformes: Ctenoluciidae) in the Middle Tapajós River, Eastern Amazon, Brazil

Abstract

Larvae of Boulengerella cuvieri (Spix & Agassiz, 1829), popularly known as bicudas, were collected in the middle Tapajós River (state of Pará, Brazil) with plankton net through horizontal trawling in the subsurface of the water column and characterized using morphological analysis, meristic and morphometric, in order to provide valuable characters for identification of this species during early ontogeny. The larvae are altricial and had a standard length ranging from 3.06 to 30.06 mm, elongated and low body, head ranging from small to moderate, eyes from large to small, and from the flexion stage the maxilla and mandible began to elongate and form a pointed beak with teeth. The total myomeres range from 49 to 50 segments (32-36 preanal and 14-18 postanal). In more developed individuals, the dorsal and anal fins do not overlap, a taxonomic characteristic that, together with the total number of myomeres, differs from other sympatric congeners. We hope this study will expand the knowledge about the developmental biology of freshwater fish species from the Neotropical region.