Elephant Fishes

Gnathonemus curvirostris Boulenger. Family Mormyridae. Congo River.

Figure 2.A EOD waveform of the holotype of Petrocephalus boboto sp. n. from Yangambi (CUMV 96774) B EOD waveform of the specimen JPS-511 of Petrocephalus arnegardi from Yangambi (BMNH 2013.8.29.125). Waveform plotted with head-positivity upwards.

Figure 3.Photographs of the holotype of Petrocephalus boboto sp. n. from Yangambi, Congo River, Democratic Republic of Congo. Top photograph, the holotype specimen (56.9 mm standard length) before preservation showing appearance in life (CUMV 96774); middle and bottom photographs represent the left and right sides of the preserved holotype. Scale bar equals one centimeter.

Figure 1.Hydrographic system of the Congo River basin and the type localities of Petrocephalus boboto sp. n. (black-filled star) at Yangambi, Democratic Republic of Congo, Petrocephalus arnegardi sp. n. (gray-filled star) at Odzala-Kokua National Park, Republic of the Congo and Petrocephalus binotatus (white-filled star) at Ikengo, near Mbandaka, Democratic Republic of Congo.

Figure 4.Phylogeny of Petrocephalus (23 species, 52 specimens) estimated by maximum likelihood analysis of cytochrome b nucleotide sequences. Mormyrin Gnathonemus petersii, Mormyrops nigricans and Myomyrus macrops were used as outgroups to root the tree. Numbers at internal branches are bootstrap proportions (in %) shown only for interspecific relationships and when they exceed 50%. Black-filled vertical bars to the right of the tree indicate the river basin origins of the specimens. The scale bar corresponds to 0.04 substitutions per site. Petrocephalus boboto sp. n. and Petrocephalus arnegardi sp. n. are highlighted in gray.

Figure 2.A EOD waveform of the holotype of Petrocephalus boboto sp. n. from Yangambi (CUMV 96774) B EOD waveform of the specimen JPS-511 of Petrocephalus arnegardi from Yangambi (BMNH 2013.8.29.125). Waveform plotted with head-positivity upwards.

Figure 5.Photographs of type specimens of Petrocephalus arnegardi sp. n. from Odzala-Kokua National Park, Congo River, Republic of the Congo. Top photograph, a paratype specimen (CUMV 92390, 72.0 mm standard length) before preservation showing appearance in life; middle and bottom photographs represent the left and right sides of the preserved holotype (CUMV 88074, 71.6 mm standard length). Scale bar equals one centimeter.

Figure 1.Hydrographic system of the Congo River basin and the type localities of Petrocephalus boboto sp. n. (black-filled star) at Yangambi, Democratic Republic of Congo, Petrocephalus arnegardi sp. n. (gray-filled star) at Odzala-Kokua National Park, Republic of the Congo and Petrocephalus binotatus (white-filled star) at Ikengo, near Mbandaka, Democratic Republic of Congo.

Figure 4.Phylogeny of Petrocephalus (23 species, 52 specimens) estimated by maximum likelihood analysis of cytochrome b nucleotide sequences. Mormyrin Gnathonemus petersii, Mormyrops nigricans and Myomyrus macrops were used as outgroups to root the tree. Numbers at internal branches are bootstrap proportions (in %) shown only for interspecific relationships and when they exceed 50%. Black-filled vertical bars to the right of the tree indicate the river basin origins of the specimens. The scale bar corresponds to 0.04 substitutions per site. Petrocephalus boboto sp. n. and Petrocephalus arnegardi sp. n. are highlighted in gray.

Figure 6.Top photograph, the preserved holotype of Petrocephalus binotatus (MRAC 15191; 83.2 mm standard length) collected at Ikengo near the modern locality of Mbandaka, Equateur Province, in the Central Congo basin of Democratic Republic of Congo (Photo by Wilhelm Harder, reproduced courtesy of ETI Bioinformatics); bottom photograph, a specimen of Petrocephalus arnegardi (BMNH 2013.8.29.34) before preservation showing appearance in life, from Yangambi, Congo River, Democratic Republic of Congo.