Description of a new species of Characidium Reinhardt, 1867 (Characiformes: Crenuchidae) from the Chapada Diamantina, Bahia, and redescription of Characidium bimaculatum Fowler, 1941 - Melo, Marcelo Roberto Souto de; Espíndola, Vinicius C (Zootaxa, 2016)