Genetic analysis on one species of Gigantorhynchus places it with the related genus Mediorhynchus in the family Gigantorhynchidae.

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,[a] and rhúnkhos, meaning snout, nose, or beak, which describes the characteristic proboscis in this genus of Acanthocephala.

[2] Males of all species possess eight cement glands which are used to temporarily close the posterior end of the female after copulation.

[11] Intermediate hosts include two species of termites from Brazil (Labiotermes emersoni and Orthognathotermes heberi).

[3] Morphological traits used to distinguish the species include a cylindrical proboscis with a crown having eighteen large hooks followed by 21 to 23 small rootless spines arranged in two longitudinal rows.

The crown is separated from numerous small, rootless spines by a short space without hooks.

Twenty-one to twenty-three small, rootless spines are arranged in longitudinal rows 0.05 to 0.08 mm long.

[12] This species is named in honour of Carlos Rodríguez López-Neyra de Gorgot, a Spanish parasitologist.

[16] Another survey found nearly 100% of the Brown four-eyed opossum were infected with this parasite in the Darien Province of Panama and the Departments of Chocó, Meta, and Nariño in Colombia.

It was named in honour of Dr. Javier Ortiz de La Puente, a Peruvian ornithologist from the Museum of the University of San Marcos, Lima, Peru who collected the brown four-eyed opossum from La Merced, Junin, Peru, which later was determined to have been infested with this new species of acanthocephalan.

[12][18] Gomes (2019) considers this Gigantorhynchus species to be incorrectly assigned due to a lack of information including missing registration number and deposit of specimen in a collection, missing type host species, unusual hook arrangement and number, and the description being based on only two immature females.

The body is ringed and has a cylindrical shape with a complete segmentation consisting of a union in dorsal and ventral regions.

The male genitals occupy one quarter of the length of the body and contains elliptical testicles and eight peripheral prostate glands.

[22] Gigantorhynchus species infest marsupials and myrmecophagids (anteaters) in Central and South America and possibly a baboon from Africa.

[23] Cystacanths, the larval state of an Acanthocephalan, of G. echinodiscus were found in the hemocoels of soldier termites, the intermediate host.

[24] There are no reported cases of any Gigantorhynchus species infesting humans in the English language medical literature.