Rediscovery and description of Paramormyrops sphekodes (Sauvage, 1879) and a new cryptic Paramormyrops (Mormyridae: Osteoglossiformes) from the Ogooué River of Gabon using morphometrics, DNA sequencing and electrophysiology

Species of the African electric fish in the genus Paramormyrops Taverne, Thys van den Audenaerde & Heymer, 1977 constitute a recently recognized species flock with an impressive diversity of electric signals, but only modest morphological differentiation. For more than a century, confusion has surrounded the identity of Paramormyrops sphekodes (Sauvage, 1879), the earliest described species in this genus. Here we compare the morphometrics of type material to new specimens collected at the type locality on the Ogooué River of Gabon from which we additionally study DNA sequences and electric organ discharges (EODs). Based on our findings, we revise the diagnosis and description of P. sphekodes and also identify and describe a new species of Paramormyrops that is large, common and widespread in the Ogooué River basin, but cryptic and easily confounded with P. sphekodes. We designate as lectotype of P. sphekodes a specimen formerly regarded, in error, as the holotype and a second specimen originally collected with the lectotype as paralectotype. We conclude that only nine additional specimens can be identified with confidence as P. sphekodes: four from the type locality and five from a second site 45 km away. Instead of being widespread as previously thought, P. sphekodes may be restricted to a small region of the upper Ogooué River basin. Additionally, we present a revised diagnosis for the genus Paramormyrops Taverne et al., 1977, and key to species from Lower Guinea. This study illustrates the value of vouchered EOD recordings and of revisiting type localities, and lays a foundation for additional systematic work on this group.