Morphology Data of Xenocharax crassus
Identification keys
Abnormalities
Main Ref. Ibala Zamba, A., V. Mamonekene, E. Vreven and M.L.J. Stiassny, 2016
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
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth terminal
Type of scales
Diagnosis

Diagnosis: Xenocharax crassus is distinguished from Xenocharax spilurus by the presence of a large black mark located anteriorly on the dorsal fin, vs. absence; a small, round, black spot at the posterior half of the caudal peduncle and covering a total of 4 to 6 scales, ±2 to 3 scales in horizontal and vertical direction alike, vs. a large ovoid spot covering a total of about 35 to 46 scales, ±8 to 10 scales in horizontal and vertical direction alike; and a wider mouth, 29-34% of head length vs. 24-29% (Ref. 114931). In addition, for the specimens of similar sizes, X. crassus has a shorter dorsal-adipose distance than X. spilurus; further, most X. crassus specimens have 6 supraneurals vs. 7 in X. spilurus (Ref. 52343, 114931).

Description: A large, robust species; body laterally compressed, relatively high, head length 28.0-33.2% of standard length, proportionally longer in smaller specimens; interorbital width broad, but overlapping range of X. spilurus; mouth terminal and wide; premaxillae with two rows of short, stout, bicuspid teeth, 32-38 in outer row; maxillae, each with 5-9 bicuspid teeth along anterodorsal margins and lower jaw with three rows of bicuspid teeth, 31-37 in outer row (Ref. 52343, 114931). Dorsal-fin origin in advance of vertical through pelvic-fin insertion; pelvic-fin origin below anterior half of dorsal-fin base approximately at level of 5th to 8th fin ray; adipose scaled basally (Ref. 114931). Scales: 74 lateral line scales, 26 transversal scales (Ref. 52343).

Colouration: In life, body generally greyish, darker dorsally over dorsal midline from head to caudal peduncle; flanks with 11-14 faint vertical bars extending from upper to lowerflanks only slightly below lateral line; in addition, flanks of some specimens variously spotted with darkly pigmented scales randomly arrayed over lower flanks below lateral line; small, round, black spot on posterior half of caudal peduncle at level of lateral line and covering a total of 4 to 6 scales, ± 2 to 3 scales in horizontal and vertical direction alike; dorsal fin dark with a large black mark anteriorly, extending over basal quarter to half of fin; pectoral and pelvic fins translucent yellowish; anal and caudal fins dark yellowish (Ref. 114931). In preservation, head and body dark brown dorsally, becoming pale yellow ventrally; opercle with large blackish blotch covering ventral region; vertical black bands clearly visible on flanks; ventral surface of head and body light yellowish-white; small, round, black spot visible at base of caudal peduncle; dorsal fin yellowish with dark patch anteriorly; pectoral, pelvic, anal and caudal fins yellowish-white to transparent with faint brownish pigmentation along or in-between rays (Ref. 114931).

Ease of Identification

Meristic characteristics of Xenocharax crassus

Lateral Lines Interrupted: No
Scales on lateral line 65 - 76
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line 12 - 14
Scale rows below lateral line
Scales around caudal peduncle 23 - 25
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 16 - 22
Vertebrae
preanal 20 - 22
total

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total 0 - 0
Soft-rays total 18 - 22
Adipose fin present

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 13 - 15

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   10 - 10
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Spines     0
Soft-rays   11 - 11
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Boden, Gert
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