Biology of Finfish and Shellfish (2+1)

Cynoglossidae

• Cynoglossid larvae are initially elongate to moderate in depth, compressed and bilaterally symmetrical.
• They become extremely compressed and deeper after notochord flexion is complete.
• The head and trunk are initially much deeper than the tapering tail.
• The tail gradually becomes deeper, but it remains less deep than the rest of the body.
• There are 43-59 myomeres (7-10+ 36-50).
• The gut is thick and coiled into a single, large loop and protrudes markedly from the ventral body margin.
• The anus is usually somewhat trailing and in flexion and post flexion larvae projects to the right and posterior to the origin of the anal fin.
• The gas bladder is located over the posterior portion of the gut.
• The rostral hook originates on the head as an enlargement under the bases of the elongate dorsal rays.
• The round eye is initially moderate to large, but is small to moderate in post flexion larvae.
• In larvae larger than 2.5 mm the eye has a prominent posterior projection that persists until metamorphosis.
• The stage and size at which eye migration begins from late flexion to late post flexion and from 11 to 30 mm.
• Head spines are absent.
• The non elongate dorsal fin rays and the anal fin rays develop concurrently.
• The dorsal and anal fins are confluent with the caudal fin once it forms and together form a continuous fin from snout to anus.
  
• Large, paddle-shaped pectoral fins are present but rays never develop.
• The pectoral fins degenerate during transformation.
• Pigment may also appear on the dorsal surface of the gas bladder, elongate dorsal rays, pectoral fin and, in postflextion larvae, midlaterally on the tail.