Description of nine new species of Phenacogaster (Ostariophysi: Characiformes: Characidae) and notes on the other species of genus

Description of nine new species of Phenacogaster (Ostariophysi: Characiformes: Characidae) and notes on the other species of genus. Nine new species of Phenacogaster Eigenmann, 1907 are described: Phenacogaster capitulatus sp. nov. from the Neshuya River system, Ucayali River basin; Phenacogaster maculoblongus sp. nov. from the upper Cuyuni River, and tributaries of the lower Orinoco River; Phenacogaster napoatilis sp. nov. from the Napo River system, upper Amazon River basin; Phenacogaster ojitatus sp. nov. from the Xingu River system; Phenacogaster prolatus sp. nov. from the Orinoco River, canal Casiquiare and upper and middle Negro River; Phenacogaster retropinnus sp. nov. from the Negro, Madeira and Xingu river systems; Phenacogaster simulatus sp. nov. from the Potaro River, Essequibo drainage; Phenacogaster wayampi sp. nov. from the Oiapoque River, and Phenacogaster wayana sp. nov. from the Corantijn (Suriname), Maroni, Mana, Sinnamary and Approuague rivers (French Guiana). The geographic distribution of P. megalostictus, previously recorded for the Negro River, Amazon River system, is restricted to the Essequibo River system, Guiana. The distribution of P. carted, previously known only from the type-locality (Cuyuni River, Guyana), is extended to the lower Orinoco River. The reduction of the latero-sensory canal, mentioned in the literature as an autapomorphy for P tegatus was observed in three additional species of Phenacogaster. The posterior humeral spot, found only in P. tegatus, is herein considered autapomorphic for the species. Diagnoses are given for previously described species based on the analysis of type material and additional specimens, and a key to the species of the genus is provided.