Giganthorhynchidae

Gigantorhynchida is an order containing a single family, Gigantorhynchidae of Acanthocephala (thorny-headed worms, also known as spiny-headed worms) that parasitize vertebrates by attaching themselves to the intestinal wall of their host. There are over 60 species classified into three genera in Gigantorhynchida Gigantorhynchus, Intraproboscis, and Mediorhynchus.

Taxonomy
Phylogenetically, the family Gigantorhynchidae is sister to the family Moniliformidae, represented by sequences of Moniliformis Moniliformis that form a supported monophyletic group. The group formed by Gigantorhynchidae and Moniliformidae suggest it to be a sister to the group formed by sequences of Macracanthorhynchus ingens and Oncicola venezuelensis A new taxonomic analysis has been performed.

Genera
Gigantorhynchida contains three genera.

Gigantorhynchus
The genus Gigantorhynchus contains six species with G. echinodiscus as the type species. It was described by Hamann in 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. Gigantorhynchus species infest marsupials and myrmecophagids (anteaters) in Central and South America.

Intraproboscis
The genus Intraproboscis Amin, Heckmann, Sist, and Basso, 2021 contains one species, I. sanghae. It was found infesting the African black-bellied pangolin (Phataginus tetradactyla) in the Central African Republic.

Mediorhynchus
Mediorhynchus Van Cleave, 1916 contains at least 59 species.

Distribution
Gigantorhynchus is found in mammals in South America and baboons in Africa. Intraproboscis is found in mammals in Africa, and Mediorhynchus is found in birds worldwide.