Morphology Data of Fontitrygon margaritella
Identification keys
Abnormalities
Main Ref. Compagno, L.J.V. and T.R. Roberts, 1984
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs claspers (m)
Different appearance
Different colors
Remarks

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral other
Cross section flattened
Dorsal head profile
Type of eyes more or less normal
Type of mouth/snout
Position of mouth sub-terminal/inferior
Type of scales placoid scales
Diagnosis

Diagnosis: Dasyatis margaritella is the smallest dasyatid in West Africa (Ref. 26277). It is most similar to Dasyatis margarita, which is larger and has a larger pearl spine, and more numerous pectoral radials, 133-135 vs. 116-127 in D. margaritella (Ref. 26277). It is also similar to D. garouaensis, which has a much flatter disc and a longer snout (Ref. 26277).

Description: Disc rounded-oval, width and length roughly equal, with broadly rounded corners, and moderately flat; its medial lobe broad-based and exserted, its anterior margin concave; disc depth 11.0-15.5% of disc width, disc width 0.9-1.1 times disc length (Ref. 26277, 81259, 81625). Middle third of disc covered with small heart-shaped or circular flat denticles; no enlarged thorns on disc or tail (Ref. 26277). Snout moderately long, acutely pointed, giving the body a slightly pentagonal appearance (Ref. 26277, 81259). Eyes and spiracles about equal size; nasal curtain with fringed posterior margin and groove extending from nasal flap to mouth corners (Ref. 81625). Upper jaw slightly undulate, with a great number of tooth rows: 24-41/34-50; 5 fleshy papillae on mouth floor (Ref. 7397, 81259, 81625). Pelvic fins projecting only slightly from posterior disc margin (Ref. 81625). Total number of pectoral radials 113-127 (Ref. 7397, 81259, 81625). Tail long and slender, tapering from base, with numerous sharp denticles posterior to stings; tail base about one-half of interorbital length, depressed in cross-section, horizontally oval; dorsal tail-fold reduced to a low keel posterior to caudal stings, but ventral tail-fold moderately high (Ref. 81625). Pearl spine always present and moderately large (Ref. 26277).

Colouration: Disc and pelvic fins gray-brown above, without spots or prominent markings, white below and without a marginal dark band (Ref. 26277, 81625).

Ease of Identification

Meristic characteristics of Fontitrygon margaritella

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) present
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total 116 - 128

Fins

Dorsal fin(s)

Attributes
Fins number
Finlets No. Dorsal   
Ventral  
Spines total
Soft-rays total
Adipose fin

Caudal fin

Attributes

Anal fin(s)

Fins number
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  transformed to 'aerofoils'
Spines     
Soft-rays   
Pelvics Attributes  more or less normal
Position    abdominal
Spines     
Soft-rays   
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