T Musschoot

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).

Re-establishment of the genus Monostichodus Vaillant 1886 (Characiformes, Distichodontidae)

Pellegrin rejected the validity of Monostichodus elongatus, described by Vaillant and type species of the genus Monostichodus, based on the lack of a proper species description, and redescribed Vaillants specimens as Hemistichodus vaillanti. After review of the relevant articles in the International Code of Zoological Nomenclature, however, no arguments were found to consider M. elongatus as a nomen nudum. This implies that Hemistichodus should be considered as a junior synonym of the genus Monostichodus, which includes three valid species: M. elongatus (with Hemistichodus vaillanti as a junior synonym), M. mesmaekersi and M. lootensi.