Acanthocephala

Name

Greek: acantha = thorn, cephale = head.

Classification

Phylum or lower group of Metazoa.

General Information

Adult members of the Acanthocephala are highly specialized heterosexual, intestinal parasites that take up nutrition parenterally since they have no intestine. Vertebrates are used as final (definitive) hosts, arthropods as intermediate hosts (Table 1). The body consists of 2 major parts, the praesoma and the metasoma. The praesoma comprises the proboscis, armed with a set of specific hooks (Fig. 1, Attachment), a more or less pronounced neck, the proboscis receptacle, and the 2 lemnisci (Figs. 4, 16), which are cylindrical appendages of the praesomal tegument. The tube-shaped metasoma (= trunk) is bounded by a solid body wall, enclosing the pseudocoel, which in addition to liquid is mainly filled with male or female sexual organs.

Figure 1

SEMs of acanthocephalan praesomae.