A New Species of Characidium (Characiformes: Crenuchidae) from Coastal Basins of Serra do Mar, Southeastern Brazil

Characidium litorale, a new species of characidiin fish, is described from coastal basins of the northeastern portion of the Serra do Mar, State of Rio de Janeiro, southeastern Brazil. The species presents thin dark secondary bars (vertical streaks not associated with dorsal marks) positioned between the primary vertical bars (bars directly associated with well-defined dorsal marks) on the side of the body. Characidium litorale is the first species described from the southeastern Brazilian coastal drainages with basicaudal black spot well defined, fully scaled isthmus, and hyaline fins. Unlike other species of Characidium from this region (predominately found associated with rocky substrate), C. Morale has psammophilous habits. An identification key to the species of Characidium occurring sympatrically with the new species is presented.