Shell torsion and life habit in the recent mytilid bivalve Modiolus philippinarum
Abstract Modiolus philippinarum lives byssally attached to a rocky substrate, with the shell completely embedded in a mat of algal filaments and byssus. This mode of life possesses aspects in common with both epibyssate and endobyssate habits. Shell torsion in M. philippinarum has the same general adaptive value as in other twisted bivalves. However, the peculiar life habit of M. philippinarum results in significant differences with respect to truly endobyssate twisted forms.