Main Ref.	Poutiers, J.M., 1998
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	Shell solid, reaching a very large size, obliquely ovate in outline, with posterior ear drawn out into a narrow, more or less elongated, wing-like expansion; slightly inequivalve, left valve a little more inflated and with a weak rounded fold radiating from umbo to posteroventral end of shell. Outline of shell variable, initially narrowly oblique, later greatly expanding ventrally and almost as high as long, or even higher than long in larger specimens and with the posterior ear relatively short. Interior of shell with a wide non-nacreous margin ventrally. Colour: outside of shell plain dark brown to black. Interior silvery and brilliantly nacreous, with a broad, posteroventrally expanded, glossy black margin.
Ease of Identification

Meristic characteristics of Pteria penguin

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