Petrocephalus okavangensis Kramer, Bills, Skelton & Wink, 2012

Family:  Mormyridae (Elephantfishes)
Max. size:  9.5 cm SL (male/unsexed)
Environment:  demersal; freshwater,
Distribution:  Africa: Okavango River drainage system, from the headwaters in Angola in the north, to the Makgadikgadi Salt Pan region in Botswana in the south (Ref. 79613, 91771). Also reported from the Zambezi in Angola (Ref. 120641).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 20-24; Anal spines: 0-0; Anal soft rays: 27-32. Diagnosis: Body depth 26.1-34.8% of standard length; head length 23.2-27.4% of standard length; preanal length 53.8-61.9% of standard length; dorsal fin length 14.5-19.5% of standard length; length of anal fin 24.7-28.6% of standard length; depth of caudal peduncle 26.4-34.9% of its length; number of anal fin rays 27-32; number of scales in lateral line row 37-38; number of scales around caudal peduncle 12 (Ref. 91771). Description: Body oval shape; head with distinctly pointed nose in most specimens, with a small ventrally positioned subterminal mouth, situated ventral to the eye; head and body dorsolaterally compressed (Ref. 91771). Dorsal fin origin situated about two-thirds of standard length from snout, oblique orientated, anteriorly higher and posteriorly lower, distal margin crescentic with anterior two or three rays longer than posterior rays, 20-24 dorsal fin rays (Ref. 91771). anal fin longer than dorsal fin, opposite dorsal fin with slightly more anterior origin, obliquely orientated, anteriorly lower and posteriorly higher, anterior 10 or so rays longer than posterior ones, especially in males where they also appear stronger, margin broadly rounded, rays posterior to first 10 with distal margin straight, 27-32 anal fin rays (Ref. 91771). Scales cycloid with reticulate striae, scales extending anteriorly to operculum and pectoral fins; scales in lateral series 37-38; scales on caudal peduncle circumference, 12 (Ref. 91771). Caudal peduncle slender, subcylindrical entire length, usually 18.2-23.0% of standard length (Ref. 91771). Colour: In life grey-silver or brownish-silver, then with gold-olive hue, anal fin base emphasized by black line, less distinct for dorsal fin base, first few rays of unpaired fins darker, irregular shaped dark spot under dorsal fin origin, sometimes vivible only on one body side, throat and belly very fair, back dark, paired fins light and transparent (Ref. 91771). In preservation between ochre and light brown; for some preserved specimens the dark spot below dorsal fin seems to have faded (Ref. 91771).
Biology:  Hardy and eurytopic species, common in both swamp and river (Ref. 79613). Collected under papyrus root stocks in the Guma Lagoon (Ref. 91771).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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