Figure 1. (A) Plot of principal components two and three (with percentage of total variance) of 31 log-transformed biometric data for 168 Auchenoglanis specimens; (B) plot of principal components two and three of 27 log-transformed biometric data for 168 Auchenoglanis specimens (all three barbel lengths, and combined premaxillary tooth plate width omitted); (C) ratio of postorbital to preorbital head length plotted against head length (measured until end of supraoccipital process) for 169 Auchenoglanis specimens. Type specimens are indicated by large symbols. For the A. biscutatus group: black circle: A. biscutatus holotype; grey circles: A. senegali types. For the A. occidentalis group: black triangle: A. occidentalis holotype; white triangles: A. o. tanganicanus types; white inverted triangles: A. acuticeps types; grey triangles: A. o. tchadiensis types; grey inverted triangles: A. wittei types. The Oxyglanis sacchii holotype is not included because its bad, dried state compromised many measurements.