Designation of a neotype for Synodontis schall (Bloch and Schneider, 1801) and description of two new species of Synodontis (Siluriformes: Mochokidae)

A morphometric study of 105 specimens of Synodontis schall, including most type specimens of all nominal species considered junior synonyms of S. schall has been undertaken. Two new species S. ouemeensis and S. kogonensis are described from the Ogun (Nigeria), Oueme (Benin) and Mono (Togo) basins, and the Kogon and Fatala (Guinea) basins, respectively. A neotype is designated for S. schall. The two new species differ from S. schall mainly by the width of the premaxillary toothplate (12.9–24.3% HL for S. schall vs. 21.6–32.7% HL), and can be distinguished one from the other by differences in orbit diameter (20.5–26.8% HL for S. ouemeensis vs. 19.4–21.0% HL for S. kogonensis) and prepectoral length (23.4–28.2% SL for S. ouemeensis vs. 21.6–23.3% SL for S. kogonensis).