Petrocephalus wesselsi Kramer & van der Bank, 2000

Original description from Kramer and van der Bank (2000):

The head is broadly rounded with a small ventrally positioned subterminal mouth, situated ventral to the eye; head and body dorsolaterally compressed. Dorsal fin (a) situated about three fourths of standard length from snout, (b) obliquely oriented with anteriorly higher and posteriorly lower, (c) distal margin sharply crescentic with anterior two or three rays about 5 times longer than posterior rays together forming a point, and (d) number of rays 18 (N = 4), 19 (N = 9), 20 (N = 21), 21 (N = 5). Anal fin (a) directly opposite to dorsal fin and obliquely oriented, The head is broadly rounded with a small ventrally positioned subterminal mouth, situated ventral to the eye; head and body dorsolaterally compressed. Dorsal fin (a) situated about three fourths of standard length from snout, (b) obliquely oriented with anteriorly higher and posteriorly lower, (c) distal margin sharply crescentic with anterior two or three rays about 5 times longer than posterior rays together forming a point, and (d) number of rays 18 (N = 4), 19 (N = 9), 20 (N = 21), 21 (N = 5). Anal fin (a) directly opposite to dorsal fin and obliquely oriented, (b) anteriorly lower and posteriorly higher, (c) anterior 10 or so rays longer than those posteriorly, (d) margin broadly rounded, (e) rays posterior to first 10 with distal margin straight, and (f) number of rays 25 (N = 6), 26 (N = 20), 27 (N = 12), 28 (N = 1). Scales (a) cycloid with reticulate striae, except in centre and outer edge, (b) extending anteriorly to operculum, pectoral fins and pelvic fins. SPc, 15 (N = 2) and 16 (N = 37). Caudal peduncle slender and subcylindrical over the entire length, usually less than 7% in SL.

EOD triphasic with strong head-positive (P1), very strong head-negative (N), and weak second head-positive phases (P2); long duration (close to 1 ms).

Males approaching sexual maturity develop a kink in the base of the anal fin which is absent in juveniles and females where the anal fin base is straight.