Diagnosis: small supraorbital process on infraorbital IV, not reaching the rostral border of the eye; fenestra between scapulo-coracoid and cleithrum absent; interdigitation between entopterygoid and quadrate (Ref. 81644).

Description: body extremely elongate, abdominal depth 2.5-9.6% SL (mean 5.0); long dorsal and anal fins, continuous with caudal fin; distance between supraoccipital process and dorsal fin 4.6-20% SL (mean 9.2); pectoral fins present or absent, when present, length between 2.4-39.9% of skull length; pelvic fins absent in most cases, however, several specimens have both or a single pelvic fin, with length 15.8-30.6% skull length (mean 24.5); skull short, 4.8-17.8% SL (mean 9.7); skull roof (exposed bony part in between bulging jaw muscles) narrow, 10.7-35.3% (mean 21.6) skull length; jaw muscles hypertrophied but may or may not bulge (generally bulging in larger specimens); eyes bordered by small infraorbital bones, of which postorbital one has a plate-like outgrowth; internal mandibular barbel always shorter than skull, other barbels longer; maxillary barbel longest (55-151% HL, m = 93); eyes small, without free orbital rim (Ref. 81644).

Coloration: body uniformly dark to pale brown, paler ventrally or fades from dark to pale (e.g. specimens from Congo basin); unpaired fins coloured as body, paired fins usually paler (Ref. 81644).