Morphology Data of Amphilius nigricaudatus
Identification keys
Abnormalities
Main Ref. Skelton, P.H., 2007
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 elongated
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth sub-terminal/inferior
Type of scales
Diagnosis

Diagnosis: caudal fin with large, central black disc; pigmentation variable, from uniformly dark brown or brown with small spots to highly vermiculated; origin of dorsal fin one head length behind head; dorsal fin base extends behind origin of pelvic fin origin; dorsal fin leading ray distinctly shorter than leading edge of fin; caudal fin with 6 + 7 principal rays; caudal peduncle short (6-7.5 times in SL) and deep (length 1-1.6 times depth); snout shorter than post-orbit length; eyes placed equidistant from hind margin of head and tip of snout (mid-way along head) or nearer to tip of snout (Ref. 81646).

Description: body slender and low, slightly depressed anteriorly, width tapers to a compressed caudal peduncle; head length 3.6-4.5 times in SL, head obtuse in front, broader behind and depressed, profile gently rounded above, flat below; branchiostegal membrane deeply cleft mid-ventrally; snout shorter than post-orbit; nostrils in mid-snout, narrowly separated; eyes small, relatively widely separated (interorbital width 2.2-3.5 times orbit diameter), confluent with head; mouth subterminal; lips fleshy; teeth caniniform in pad on premaxilla and band along lower jaw; barbels slender and filamentous, maxillary pair longest, extending to above pectoral fins; fins short and broad; origin of dorsal fin one head length behind head; dorsal fin base extends over pelvic fin origin; dorsal fin rounded, leading ray shorter than leading edge; pectorals short, not reaching pelvics, broad, leading ray slender, pectinate and padded; pelvics short, not reaching anal base, rounded, lead ray slender, pectinate and padded; anal fin short and slender, reaching close to base of caudal; caudal fin broad, emarginate, crenellated fleshy flap over base; adipose fin low, extends from above anal fin to procurrent ridge of caudal fin; anus and genital pore close to pelvic fin bases (Ref. 81646).

Coloration: colour pattern varies considerably between individuals and localities but commonly uniformly dark brown with fine black spots over whole lateral and upper body and head, ventral surface from head to anal fin light brown or cream; caudal fin yellow with large central black spot; dorsal fin rays brown with clear membranes; all other fins without distinct pigmentation or pattern; variations from this pattern include an increasing degree of larger spots along flanks and upper body to heavily spotted individuals with background pigment a light brown; a starkly different vermiculated pattern lacking a black spot on caudal observed in one population from the lower Ogowe (Ref. 81646).

Ease of Identification

Meristic characteristics of Amphilius nigricaudatus

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Barbels 6
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 0
Soft-rays total 7
Adipose fin present

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number 1
Spines total 0
Soft-rays total 7 - 7

Paired fins

Pectoral Attributes  
Spines     0
Soft-rays   9
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Spines     0
Soft-rays   6
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