Morphology Data of Megachasma pelagios
Identification keys
Abnormalities
Main Ref. Compagno, L.J.V., 2001
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs no special organs
Different appearance males alike females
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 placoid scales
Diagnosis

Body stout, tapering posteriorly (Ref. 6871), tadpole-like with larger head and tapering trunk and tail (Ref. 47786). Snout extremely short but broadly rounded (Ref 43278, 47786). Head huge, blubbery (Ref. 6871). Mouth very broad and terminal on head, with corner extending behind the eyes (Ref. 6871, 43278). Jaws huge, protrusible anteriorly but not greatly distensible laterally (Ref. 43278, 47786), lower jaw extending to snout tip (Ref. 6871). Teeth very small, numerous, hooked (Ref. 43278, 6871, 47787). Gill slits moderately long, not reaching dorsal surface of head (Ref. 6871; 43278), internal gill slits lined with dense rows of papillose gill rakers (Ref. 43278). Eyes semicircular (Ref. 47786), with no nictitating membrane (Ref. 43278, 6871, 47786). Two dorsal fins, relatively low and angular; small anal fin; long, narrow pectoral fins; moderate-sized pelvic fin; caudal fin asymmetrical, non-lunate, with a short and strong ventral lobe; upper pre-caudal pit only; caudal peduncle without keels or ridges (Ref, 6871, 43278).

Ease of Identification easy to distinguish from other species.

Meristic characteristics of Megachasma pelagios

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
Vertebrae
preanal
total 125

Fins

Dorsal fin(s)

Attributes
Fins number 2
Finlets No. Dorsal   
Ventral  
Spines total 0 - 0
Soft-rays total
Adipose fin absent

Caudal fin

Attributes heterocercal; asymmetric

Anal fin(s)

Fins number 1
Spines total
Soft-rays total

Paired fins

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