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How do tongue soles differ from other flatfishes in their mouth and pectoral fins?
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pleuronectiform
Body plan and sexual dimorphism in the common sole (Solea solea) and dusky flounder (Syacium papillosum).
Tongue soles, which belong to the family Cynoglossidae, exhibit distinct anatomical characteristics that differentiate them from many other flatfishes within the order Pleuronectiformes.
Regarding their mouth and pectoral fins, tongue soles are characterized by the following:
- Mouth: Unlike many other flatfishes, tongue soles possess an asymmetrical mouth.1
- Pectoral Fins: These fishes are distinguished by having pectoral fins that are either rudimentary or entirely absent.1
In addition to these features, tongue soles are identified by their small, sinistral (left-sided) eyes and the fact that their dorsal and anal fins are confluent (united) with the caudal fin. Unlike the American soles (Achiridae) or the family Soleidae, tongue soles lack sensory papillae on the head.12