THE CAUDAL MUSCULATURE OF HOPLOPAGRUS GUNTHERI GILL (PERCIFORMES: LUTJANIDAE)

Abstract

The caudal musculature of Hoplopagrus comprises dorsal and ventral superficial flexors reinforced by a deltoid flexor tendon, dorsal and ventral deep flexors a hypochordal longitudinal muscle, a dorsal adductor, and interradials. These provide for flexion, extension, abduction, adduction, rotation, and probably circumduction of fin rays. The muscles are innervated by a spinal nerve plexus. The fin rays articulate with the caudal vertebral skeleton by a well-developed joint capsule with a synovial space. Dissection of a series embracing Palaeoniscoidei–Holostei–Teleostei suggests how there has been an evolution of specialized effectors to actuate a caudal fin of increasingly complex function. A table of synonyms of muscles of the caudal fin is included.