Apionichthys sauli is a species of sole in the family Achiridae. It was described by Robson Tamar da Costa Ramos in 2003. It inhabits the Orinoco and Meta rivers in South America. It reaches a maximum standard length of 7cm (03inches).
The species epithet "sauli" was given in honour of William G. Saul, a former curator in the ichthyology department at the Academy of Natural Sciences of Drexel University in Philadelphia, credited as one of the collectors of the type material for the species.