GBIF Taxonomic Backbone & Wikipedia Registry Profile
Description. Morphometric ratios and meristic data are given in Table 3 for the holotype and paratypes separately. Petrocephalus valentini n. sp. is a small sized species within the genus (maximum SL = 77.2 mm, holotype). Body ovoid, longer than high (2.8 ≤ SL / H ≤ 3.0, paratype average = 2.9, holotype = 2.8) and laterally compressed. Head length between 3.4 and 3.7 times in standard length (paratype average = 3.6, holotype = 3.4). Snout short (6.5 ≤ HL / SNL ≤ 8.2, paratype average = 7.4, holotype = 6.5) and round. Mouth small (4.7 ≤ HL / MW ≤ 5.8, paratype average = 5.2, holotype = 5.1) and sub-terminal, positioned under the anterior half of the eye. Eye large (2.9 ≤ HL / ED ≤ 3.2, paratype average = 3.0, holotype = 3.1). Teeth small and bicuspid, 7 – 12 (paratype median = 9, holotype = 9) in a single row in the upper jaw, 15 – 17 (paratype median = 16, holotype = 17) in the lower jaw. Dorsal and anal fins originate in the posterior half of the body (1.6 ≤ SL / PDD ≤ 1.7 and SL / PAD = 1.6). Pre-dorsal distance approximately equal to the pre-anal distance. Dorsal fin with 19 – 24 branched rays (paratype median = 22, holotype = 22). Anal fin with 24 – 26 branched rays (paratype median = 25, holotype = 25). Scales cover the body, except for the head. Lateral line visible and complete with 35 – 36 pored scales along its length (paratype median = 36, holotype = 35). Nine to 12 scales (paratype median = 11, holotype = 11) between the anterior base of the anal fin and the lateral line. Caudal peduncle relatively thin (2.2 ≤ CPL / CPD ≤ 2.5, paratype average = 2.3, holotype = 2.3). Twelve scales around the caudal peduncle. Skin on head thick, turning opaque with formalin fixation. Knollenorgans clearly organized into two visible rosettes (the Augenrosette and the Nackenrosette). During our examination of specimens, we were uncertain about the definitive presence of the third rosette, the Kehlrosette, as this structure did not appear to us to be as distinct as it is in some other species (e. g., P. binotatus). Recently, however, more definitive analysis using toluidine blue staining of the skin suggests that the Kehlrosette is in fact present, but it is indeed smaller and harder to discern than in other Petrocephalus (M. Hollmann and B. A. Carlson, unpub. obs.). Holotype (m) Paratypes (n = 8) Min – Max Mean Std – Dev Min – Max Median Meristic counts: Number of scale rows between the anterior base of the 11 9 – 12 11 anal fin and the lateral line (SDL) Number of teeth in the upper jaw (TUJ) 9 7 – 12 9 Number of teeth in the lower jaw (TLJ) 17 15 – 17 16 Live coloration (Fig. 5 A). Body uniformly white-silver, with two faint black patches, sometimes hardly distinguishable: (1) a dorsal mark on each side of the body, below the anterior base of the dorsal fin under the second to the sixth rays; (2) an ovoid / crescent-shaped mark centered at the base of the caudal fin (sometimes the center of this second mark is less distinguishable than the two arms of the crescent), with each arm slightly extending onto the upper and lower parts of the caudal fin. There is no melanin marking at the base of the pectoral fins. Fins translucent.
