Morphology Data of Petrocephalus mbossou
Identification keys
Abnormalities
Main Ref. Lavoué, S., J.P. Sullivan and M.E. Arnegard, 2010
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section compressed
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth sub-terminal/inferior
Type of scales cycloid scales
Diagnosis

Diagnosis: Petrocephalus mbossou is distinguished from all other Petrocephalus species in Central Africa by the following combination of characteristics: dorsal fin with 22-24 branched rays; anal fin with 26-28 branched rays; mouth inferior and small, with ration head length and mouth width 4.2-5.1, with 9-11 teeth in a single row in the upper jaw and 14-22 teeth in a single row in the lower jaw; distance from the anterior extremity of the snout to the corner of the mouth only 2.8-3.4 times in head length (Ref. 85331, 113655). Weak pigmentation pattern with the presence of two black markings on each side of the body: (1) an irregular patch below the anterior base of the dorsal fin (first to sixth/seventh rays); (2) an irregularly-shaped mark centered at the base of the caudal fin that does not extend onto the rayed portions of the upper and lower caudal fin lobes (Ref. 85331).

Description: Body ovoid, longer than high, the ration standard length and height 2.6-3.0, and laterally compressed (Ref. 85331, 113655). Head length 3.3-3.6 times in standard length (Ref. 113655). Eye large, the ratio head length and eye-diameter 3.3-3.8 (Ref. 85331, 113655). Snout short, the ratio head length and snout length 5.2-7.2, and round (Ref. 85331, 113655). Mouth small, the ratio head length and mouth width 4.2-5.1, opening ventrally under the posterior half of the eye (Ref. 85331, 113655). Teeth small and bicuspid, 9-11 in a single row in the upper jaw, 14-22 in a single row in the lower jaw (Ref. 85331, 113655). Caudal peduncle relatively thin, the ratio caudal peduncle length and caudal peduncle depth 2.3-2.9 (Ref. 85331, 113655). Both the dorsal and anal fins originate in the posterior half of the body; the pre-dorsal distance is slightly greater than the pre-anal distance; dorsal fin with 22-24 branched rays; anal fin with 26-28 branched rays (Ref. 85331, 113655). Scales cover the body, except for the head; lateral line visible and complete with 35-37 pored scales along its length; 12 circumpeduncular scales (Ref. 85331, 113655). Skin on head thick, turning opaque with formalin fixation, and containing numerous knollenorgan electroreceptors organized into only two rosettes (Ref. 85331).

Colouration: Body mostly white-silver; dorsum slightly darker than the rest of the body; pigmentation pattern consists of two distinct black markings: a black patch of irregular shape below the anterior base of the dorsal fin, and an irregularly-shaped mark centered at the base of the caudal fin that does not extend onto the rayed portions of the upper and lower caudal fin lobes; the fins themselves are translucent (Ref. 85331).

Ease of Identification

Meristic characteristics of Petrocephalus mbossou

Lateral Lines Interrupted: No
Scales on lateral line 35 - 37
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 12 - 12
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total 0 - 0
Soft-rays total 22 - 24
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 26 - 28

Paired fins

Pectoral Attributes  more or less normal
Spines     
Soft-rays   
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Spines     
Soft-rays   
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Bailly, Nicolas
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