The Musculature of Ophryotrocha labronica (Polychaeta: Dorvilleidae). Journal of Morphology 269 (12): 1489.

The dorvilleid polychetes belonging to the genus Ophryotrocha are considered model organisms for several types of scientific investigations. Yet, until now, there is no study on the muscular arrangement of these species.The F-actin muscular subset of the species Ophryotrocha labronica was labeled with phalloidin and the architecture of the system was threedimensionally reconstructed by means of confocal laser scanning microscopy (CLSM). The body wall contained transverse and bracing musclesand five longitudinal muscle strands: two dorsolateral, two ventral and one ventromedial. In the prostomium, several muscles were observed: longitudinal, transverse, cross, rostral, and radial muscles. The transverse muscles extended from the dorsal to the ventral sides, where they terminated before reaching the midline. The prostomium was connected with the pharyngeal bulb through two pairs of longitudinal and cross muscular strands.A circumbuccal complex was observed in the ventral side near the mouth. In the parapodia, the muscles were grouped in a parapodial complex composed by several elements: longitudinal, diagonal, oblique, acicular and bristle-sac muscles. The general architecture of the muscular system of O. labronica was very similar to that of Dorvillea kastjani, but differed by the peculiar organization of head musculature and bracing muscles.