Main Ref.	Leal, J.H., 2003
Appearance refers to

Sex attributes

specialized organs
different appearance
different colors
remarks

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Diagnosis	Diagnostic features: Shell rectangular, elongate (twice as long as wide), equivalve. Sculpture of about 20 to 30 irregular radial ribs, and fine concentric threads that cross-ribs and interspaces. Byssal gap present opposite to hinge, moderately narrow. Hinge long. Colour: creamy white, streaked with reddish to dark brown wavy bands. Periostracum brown and dense on fresh shells, covering colour pattern almost completely (Ref. 344).
Ease of Identification

Meristic characteristics of Arca zebra

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

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
	spines
	soft-rays
Pelvics	Attributes
	Position
	spines
	soft-rays