THE MUSCULAR SYSTEM OF THE PARASITE OF THE STERLET Acrolichanus AURICULATUS (TREMATODA: ALLOCREADIIDAE)

Abstract

The paper presents data of the histochemical study of the muscular system of trematode Acrolichanus auriculatus, an intestinal parasite of the sterlet. Using fluorophore-conjugated phalloidin and confocal scanning laser microscopy, the musculature of the body wall, oral and ventral suckers, and digestive system of the parasite were described. The body wall musculature of A. auriculatus contains three layers of muscle fibers: circular, longitudinal, and diagonal muscle fibres. The distribution of muscle fibers along the parasite body were irregular; there were no diagonal muscle fibers in the posterior part of the body. In the region of the lower edge of the genital pore, a complex of muscle fibers was identified which extended from the lower edge of the genital pore to different directions. Several types of muscle fibers were found in oral and abdominal suckers. In the (ventral, dorso-lateral, and dorso-medial) lobes of the oral sucker, the transverse and longitudinal muscle fibers were identified. We described muscles of the pharynx that contained longitudinal, circular, and radial muscle fibers, and the intestine including longitudinal and circular muscles. A comparative analysis confirms the thesis of great diversity in the organization of the trematode muscles and shows the presence in various trematode representatives of both general (conservative) and specific characteristics typical for one or another attribute type.