Giganthorhynchidae

Giganthorhynchidae
Scientific classification
Kingdom:	Animalia
Phylum:	Acanthocephala
Class:	Archiacanthocephala
Order:	Gigantorhynchida Southwell and Macfie, 1925
Family:	Giganthorhynchidae Hamann, 1892

Gigantorhynchida is an order containing a single family, Gigantorhynchidae of parasitic worms that attach themselves to the intestinal wall of terrestrial vertebrates. Gigantorhynchida contains the following three genera:

• Gigantorhynchus Hamann, 1892

The genus Gigantorhynchus is characterized by the presence of a cylindrical proboscis with a crown of robust hooks at the apex followed by numerous small hooks on the rest of the proboscis. The body, or trunk, is long with pseudosegmentation, the lemnisci are filiform, and the testes are ellipsoid. Species of Gigantorhynchus are distinguished based on the number and size of hooks on the crown of the proboscis, the type of pseudosegmentation, and size of the ellipsoid eggs. Males of all species possess eight cement glands which are used to temporarily close the posterior end of the female after copulation. There is pronounced sexual dimorphism with the female often two or more times longer than the male.

• Intraproboscis
• Mediorhynchus Van Cleave, 1916

Taxonomy

Archiacanthocephala

Archiacanthocephala Oligacanthorhynchidae   Macracanthorhynchus ingens     Oncicola venezuelensis     Oligacanthorhynchus tortuosa     Nephridiacanthus major       Moniliformidae Moniliformis moniliformis   Gigantorhynchida   Mediorhynchus sp.     Gigantorhynchus echinodiscus

Phylogenetic reconstruction for select species in the class Archiacanthocephala