Gigantorhynchus

Gigantorhynchus
Gigantorhynchus ortizi
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Acanthocephala
Class:	Archiacanthocephala
Order:	Gigantorhynchida
Family:	Gigantorhynchidae
Genus:	Gigantorhynchus Hamann, 1892[1]
Type species
Gigantorhynchus echinodiscus (Diesing, 1851)
Other species
Gigantorhynchus lopezneyrai Gigantorhynchus lutzi Gigantorhynchus ortizi Gigantorhynchus pesteri ? Gigantorhynchus ungriai

Gigantorhynchus is a genus of Acanthocephala (thorny-headed worms, also known as spiny-headed worms) that parasitize marsupials, anteaters, and possibly baboons by attaching themselves to the intestines using their hook-covered proboscis. Their life cycle includes an egg stage found in host feces, a cystacanth (larval) stage in an intermediate host such as termites, and an adult stage where cystacanths mature in the intestines of the host. This genus is characterized by a cylindrical proboscis with a crown of robust hooks at the apex followed by numerous small hooks on the rest of the proboscis, a long body with pseudosegmentation, filiform lemnisci, and ellipsoid testes. The largest known specimen is the female G. ortizi with a length of around 240 millimetres (9.4 in) and a width of 2 millimetres (0.08 in). Genetic analysis on one species of Gigantorhynchus places it with the related genus Mediorhynchus in the family Gigantorhynchidae. Six species in this genus are distributed across Central and South America and possibly Zimbabwe. Infestation by a Gigantorhynchus species may cause partial obstructions of the intestines, severe lesions of the intestinal wall, and may lead to death.