BYSSUS ADAPTIVE MORPHOLOGY IN MYTILUS CORUSCUS, CRENOMYTILUS GRAYANUS AND MODIOLUS MODIOLUS (MYTILIDAE, BIVALVIA) FROM THE SEA OF JAPAN

摘要

We studied the adaptations of sessile bivalves to the attached mode of life in three common mytilid species. Mytilus coruscus, Crenomytilus grayanus, Modiolus modiolus were shown to be characterized by similar features of byssus organization and its distinctive parts corresponding to their functional roles. Mytilus coruscus was demonstrated to have the shortest and thickest byssal threads with the largest, more strongly reinforced attachment discs reflecting an adaptation of this species to dwelling in the marine coastal zone with active hydrodynamics. In comparison with the former mussel species, both C. grayanus and M modiolus show thinner and longer byssal threads with smaller and less strongly reinforced attachment discs, proving an adaptation of these species to the life in habitats protected from a straight action of waves.