Two new elephantfish: Cryptomyrus ogoouensis and Cryptomyrus ona

Over 200 species of mormyrid fish live in fresh waters across Africa where they navigate in their environment and communicate using electric pulses, too weak to be felt by humans, in combination with highly sensitive electroreceptor cells embedded in their skin. These fish are sometimes called elephantfish because their mouth is often shaped like a trunk. They are also known for having large brain size and unusually high intelligence.

A new weakly electric mormyrid fish genus of two new species has been described from only three specimens collected over a period of 13 years in the rivers of the Central African country of Gabon. The genus has been named Cryptomyrus, meaning 'hidden fish' in Greek. Reflecting its river of origin (Ogooue), one species now bares the name Cryptomyrus ogoouensis, while the second - Cryptomyrus ona, is named after Gabonese environmental activist Marc Ona Essangui.

For the experts: We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In C. ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.