Gigantorhynchus

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 and a width of . 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.

== Taxonomy == The name Gigantorhynchus is derived from two Ancient Greek words: gígantas, which Otto Hamann used in 1892 as a descriptor for the family and genus when grouping the larger varieties of these worms, and rhúnkhos, meaning snout, nose, or beak, which describes the characteristic proboscis in this genus of Acanthocephala. Phylogenetic analysis has been conducted on only one of the six species in the genus, G. echinodiscus, using the gene for 28S ribosomal RNA and confirms that this species forms a monophyletic group with the related genus Mediorhynchus in the family Gigantorhynchidae. The type species is G. echinodiscus.