Myology of juvenile freshwater prawn Macrobrachium amazonicum (Decapoda, Caridea): Morphology and swimming implication.

Little is known about the functional morphology of locomotion in prawns, and even fewer studies have succeeded in relating a specific muscular group to the movement of the body. The present study aimed to describe the morphology of the thoracoabdominal muscle system and its implications for swimming in juveniles of Macrobrachium amazonicum. Ten muscles were observed in the abdominal muscular system in juveniles of M. amazonicum. The complex arrangement of the anterior oblique muscle in association with the central muscles occupies most of the abdominal space. This muscular compound could promote a flexion movement of the abdomen for body propulsion as well as the tail movement during swimming. Morphofunctional continuity between thoracic and abdominal muscles could aid in locomotion and support the abdominal movement. Moreover, collagen plays a valuable role in connecting deep muscles not inserted in the carapace. Collagenous fascia could transmit the tension during the contraction of deep muscles for coordinated movement.