A comparative study on the lateral line morphology of Sebastiscus marmoratus and Trachidermus fasciatus

Abstract:

Whether the adaptation or the phylogenetic constrain impacts the morphological patterns of lateral line system is still a question in the evolutionary morphology. To approach this question, by using light and scanning electron microscopy, we compared the morphology and distribution patterns of the lateral line system in two species of Scorpaeniformes: False kelpfish(Sebastiscus marmoratus) and roughskin sculpin (Trachidermus fasciatus). The mechanosensory lateral line system of S. marmoratus and T. fasciatus are composed of canals and superficial neuromasts. The S. marmoratus, which lives in turbulent fast flowing habitats, has a developed branching canal system and fewer superficial neuromasts. In contrast, the T. fasciatus which resides in slow flowing habitats, has a simple unbranched canal system and more superficial neuromasts. Our results show that both of the patterns mainly depend on using canal lateral line system to perceive water motion with compensation of the superficial neuromasts for sensation of accurate information from the surrounding water movement. The differences of morphological patterns of the lateral line system in two systematically closely related species reflect that adaptation to the habitat hydrodynamic environment plays an important role in evolution process of morphological character formation in fish.