Morphology Data of Chrysichthys acsiorum
Identification keys
Abnormalities
Main Ref. Hardman, M., 2008
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
Type of scales
Diagnosis

Diagnosis: postcleithral process weakly expressed or absent; upper jaw extending beyond lower jaw; 14-16 gill-rakers on first arch; premaxillary and palatal toothplates with small and tightly packed teeth; vomerine toothplates widely separated and narrower than those on pterygoids; supraoccipital broad and contacting predorsal plate; body width at pectoral fin insertions 4.9-5.3 times in standard length; interorbital width 3.0-4.1 times in head length; distance between posterior nares 4.0-4.8 times in head length; maxillary barbels 4.1-5.5 times in standard length; distance between posterior margins of adipose fin and hypural plate 5.1-6.0 times in standard length (Ref. 75075).

Description: body deepest at vertical through dorsal fin spine origin, widest across pectoral girdle; dorsal head profile evenly sloping from pointed snout to posterior limit of supraoccipital, whereupon profile curves sharply to base of a short, stout dorsal fin spine bearing several small, widely separated serrae; 1st and 2nd branched dorsal fin rays approx. 1.5 times longer than spine creating a tall and flame-shaped fin; dorsal profile from dorsal fin spine to anterior limit of adipose fin flat to slightly concave, sloping gently; adipose fin low with free and rounded posterior lobe; dorsal profile sloping down towards caudal peduncle through adipose fin, beyond which procurrent rays of caudal fin slope steeply upwards to curved upper caudal fin lobe; caudal fin lobes pointed, caudal fin with 17-18 branched rays; procurrent rays of lower caudal fin lobe sloping steeply upwards to join ventral profile anterior of posterior limit of adducted anal fin; anal fin base short and embedded in adipose tissue; anal fin origin well posterior of posterior limit of adducted pelvic fin and directly beneath to slightly posterior of adipose fin origin; ventral profile between posterior limit of anal fin and anterior limit of pelvic girdle sloping gently upwards; pelvic fins rounded to spatulate, with broad bases and short unbranched rays; origin of pectoral fin spine closer to longitudinal line than pelvic fin; pectoral fin small and sharply pointed, with stout, gently curved spine bearing 10-13 (increasing with length) strongly recurved serrae; ventral profile of chest and throat flat and sloping upwards less steeply than dorsal head profile; mandibular barbels widely separated, inner pair originating well anterior of outer pair; surface of throat and buccal cavity folded with deep notch below hyoid; upper lip extending beyond lower, barely exposing premaxillary toothplate; corner of mouth with thick rictal fold forming base of narrow, flattened maxillary barbel; lateral profile of snout bluntly pointed; in dorsal view, head narrows gradually from pectoral girdle to mouth corner, whereupon it angles sharply and curves gently to median; head a trapezoid wedge with flattened sides and dorsum; orbit with free margin not interrupting dorsal profile in lateral view; dorsum of head covered with skin beneath which skull roof variably ornamented with radiating ridges and lines of small rugosities converging posteromedially; broad and deep fontanelle ridged anteriorly with irregular rugosities posteriorly, extending from midway between nares to just behind the posterior limit of orbit; dorsum of supraoccipital process broad, covered with rugosities forming irregular lines and with shallow notch posteriorly; anterior nares placed just posterior of upper lip and placed slightly wider than posterior nares, each bearing a simple nasal barbel reaching approx. anterior limit of orbit; cleithrum covered mostly by opercular flap, sigmoidal posterior margin, without postcleithral process; opercle broadly triangular, flat to slightly concave posterior margin, with radiating and branching striae converging on anteriormost corner; gill rakers on first arch broad, flattened and simple; premaxillary toothplate covered with small teeth of uniform size and density, plate fairly uniform width, narrowing slightly at medial junction and following snout profile before terminating anterior of mouth corner; small mandibular teeth of uniform size and density separated by medial septum, following the anterior profile of lower jaw and narrowing distally prior to their termination at mouth corner; anterior (vomerine) toothplates of palate broadly separated by median gap, straight, narrower than pterygoid toothplates, of even width with squared ends; posterior (pterygoid) tootplates of palate meet anterior plates but remain distinguishable, bean to tear-drop shaped narrowing posteriorly to rounded limits; teeth of palatal toothplates small, of uniform size and density (Ref. 75075).

Coloration: preserved: unpigmented venter gives way to scattered brown chromatophores on flanks increasing in density dorsally becoming reddish-brown to eventually dark brown mid-dorsally; axillary region with lowest density of chromatophores, skin covering junction of epaxials and posterodorsal margin of skull exhibits narrow band of dark pigment; dorsal surface of pectoral fin, maxillary barbel and nasal barbel light below and dark above; chromatophores of dorsal fin increasing in density distally; adipose fin uniformely covered with light scattering of chromatophores; caudal fin in smaller specimens with chromatophores concentrated on medial branched rays of each lobe and less so on upper-, lower- and medial-most branched rays creating 2 diffuse bands terminating short of tips; caudal fin pigmentation indistinct and unifrom on larger specimens; pelvic and anal fins lacking pigment (Ref. 75075).

Ease of Identification

Meristic characteristics of Chrysichthys acsiorum

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
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 14 - 16
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 1 - 1
Soft-rays total 6 - 6
Adipose fin present

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0
Soft-rays total 11 - 12

Paired fins

Pectoral Attributes  
Spines     1
Soft-rays   8 - 9
Pelvics Attributes  
Position    
Spines     0
Soft-rays   6 - 6
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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