Alary muscles and TARMS, a novel type of striated muscles maintaining internal organs positions

Presentation of poster 1507A at TAGC 2020 online.
Files include of pdf of the poster:
TAGC 2020 poster A Vincent 1507A.pdf

Alary muscles (AMs) have been described as a component of the cardiac system in various arthropods. Lineage-related thoracic muscles (TARMs) connect the exoskeleton to specific gut regions. We analysed the atypical shape and deformability of AMs and TARMs in crawling Drosophila larvae. Elimination of AMs and TARMs by targeted apoptosis showed that AMs are required for suspending the heart in proper intra-hemocelic position and opening of the heart lumen, and constrain the curvature of the dorsal trachea; TARMs are required for proper positioning of visceral organs and efficient food transit. TARMs and AMs are the first example of striated muscles connecting the skeleton to the cardiac and visceral systems, with multiple physiological functions. This instates novel anatomical and evolutionary perspectives.