part of develops from start stage end stage pectoral fin musculature superficial abductor Abductor muscle that develops from the primitive pectoral fin abductor. The abductor superficialis originates along the anterior skeletal flange of the pectoral girdle, the bundles insert to fin ray base distal processes. zebrafish_anatomy ZFA:0000685 superficial abductors TAO:0000685 abductor superficialis abductor muscle primitive pectoral fin abductor larval:days 7-13 adult