Analysis of samples of the auchenipterid catfish genus Tatia collected during a recent ichthyological survey in the Cuyuni River basin in Guyana revealed them to be an undescribed species. Comparative studies associated with the evaluation of that new species demonstrated that a sample of the genus from a right bank tributary of the Río Orinoco in Venezuela, also on the Guiana Shield, represents a second species unknown to science. The placement of Tatia musaica, previously considered incertae sedis in the Centromochlinae, is evaluated and the species is reassigned to Tatia.