How to Identify Tongue Sole

To identify Tongue Sole (Cynoglossus arel), look at these key features.

Physical Characteristics

Body shape

flat

Coloration

Dorsal side typically brownish to grayish, often with irregular darker blotches or spots, providing camouflage against the seabed. Ventral side (blind side) is whitish.

Scale type

ctenoid

Mouth position

inferior

Distinctive features

Elongated, tongue-shaped body, tapering to a pointed tail., Both eyes are on the left side of the head, with the upper eye slightly in advance of the lower eye., Small, inferior mouth, curved and asymmetrical., No pectoral fins., Dorsal and anal fins confluent with the caudal fin., Lateral line present on both eyed and blind sides, with an accessory lateral line on the eyed side.

Dorsal fin

Long, continuous, originating near the snout and confluent with the caudal fin. Typically 116-130 rays.

Tail fin

Pointed, confluent with dorsal and anal fins.

Pectoral fin

Absent.

Distinctive fins

Anal fin long, continuous, originating behind the gill opening and confluent with the caudal fin. Typically 90-106 rays. Pelvic fins are small, asymmetrical, and located on the blind side.

Identification Tips

1. 1

   Body Shape

   Look for the distinctive elongated, tongue-like body that tapers to a point.

2. 2

   Eye Placement

   Confirm both eyes are on the left side of the head, with the upper eye slightly anterior to the lower.

3. 3

   Fin Absence

   Note the complete absence of pectoral fins, a key characteristic of the family Cynoglossidae.

4. 4

   Lateral Lines

   Observe the presence of two lateral lines on the eyed side (one main, one accessory) and one on the blind side.

5. 5

   Mouth

   Identify the small, inferior, and asymmetrical mouth.

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