Electrophysiological and molecular genetic evidence for sympatrically occuring cryptic species in African weakly electric fishes (Teleostei: Mormyridae: Campylomormyrus)

For two sympatric species of African weakly electric Wsh, Campylomormyrus tamandua and Campylomormyrus numenius, we moni- tored ontogenetic diVerentiation in electric organ discharge (EOD) and established a molecular phylogeny, based on 2222 bp from cyto- chrome b, the S7 ribosomal protein gene, and four Xanking regions of unlinked microsatellite loci. In C. tamandua, there is one common EOD type, regardless of age and sex, whereas in C. numenius we were able to identify three diVerent male adult EOD waveform types, which emerged from a single common EOD observed in juveniles. Two of these EOD types formed well supported clades in our phyloge- netic analysis. In an independent line of evidence, we were able to aYrm the classiWcation into three groups by microsatellite data. The correct assignment and the high pairwise FST values support our hypothesis that these groups are reproductively isolated. We propose that in C. numenius there are cryptic species, hidden behind similar and, at least as juveniles, identical morphs.