How to Identify Small-toothed Flounder

To identify Small-toothed Flounder (Pseudorhombus jenynsii), look at these key features.

Physical Characteristics

Body shape

flat

Coloration

Dorsal surface is typically mottled brown, grey, or olive, often with irregular darker spots and blotches, providing excellent camouflage against sandy or muddy bottoms. The ventral (blind) side is white. Some individuals may exhibit ocelli (eye-like spots) on the eyed side.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Eyes on the left side of the head (sinistral), Small, pointed teeth in both jaws, Lateral line strongly arched above the pectoral fin, Presence of small, dark spots or rings on the eyed side

Dorsal fin

Originates anterior to the upper eye, with 70-80 soft rays. No spines.

Tail fin

Rounded to slightly truncate caudal fin.

Pectoral fin

Well-developed on both sides, but larger on the eyed side. 10-12 rays.

Distinctive fins

Pelvic fins are symmetrical and short, with 6 rays each. Anal fin has 55-65 soft rays.

Identification Tips

1. 1

   Eye Position

   Always check that both eyes are on the left side of the head. This distinguishes it from dextral (right-eyed) flounders.

2. 2

   Teeth

   Carefully examine the mouth for small, pointed teeth in both jaws, a key feature for the genus Pseudorhombus.

3. 3

   Lateral Line

   Note the distinct arch in the lateral line above the pectoral fin on the eyed side.

4. 4

   Coloration and Markings

   Observe the mottled brown/grey coloration and any irregular dark spots or rings on the eyed side, which aid in camouflage.

5. 5

   Fin Ray Counts

   For definitive identification, especially from similar species, accurate counts of dorsal (70-80) and anal (55-65) fin rays can be crucial.

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