Gigantorhynchus

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Gigantorhynchus
Gigantorhynchus ortizi.jpg
Gigantorhynchus ortizi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Acanthocephala
Class: Archiacanthocephala
Order: Gigantorhynchida
Family: Gigantorhynchidae
Genus: Gigantorhynchus
Hamann, 1892 [1]

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.

Contents

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, [lower-alpha 1] and rhúnkhos , meaning snout, nose, or beak, which describes the characteristic proboscis in this genus of Acanthocephala. [1] 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. [2] The type species is G. echinodiscus. [3]

Archiacanthocephala
Archiacanthocephala
Phylogenetic reconstruction for select species in the class Archiacanthocephala based on a 28S rRNA gene comparison from Gomes et. al (2019) and a 18S rDNA gene comparison from Amin et al. (2020). [2] [4]

Description

Number of proboscis hooks [2]
SpeciesHooks
G. echinodiscus18
G. lopezneyrai12
G. lutzi12
G. ortizi12
G. pesteri4
G. ungriai18

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. [2] [5] The body, or trunk, is long with pseudosegmentation, the lemnisci are filiform, and the testes are ellipsoid. [2] 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. [2] Males of all species possess eight cement glands which are used to temporarily close the posterior end of the female after copulation. [6] There is pronounced sexual dimorphism with the female often two or more times longer than the male. [2]

Anatomical measurements
Female measurements (mm)
Measurements [2] G. echinodiscusG. lopezneyraiG. lutzi [lower-alpha 2] G. ortizi [lower-alpha 3] G. pesteri [lower-alpha 4] G. ungriai [lower-alpha 5]
Length of proboscis 0.49–0.71?1.6951.45–1.720.350.189–1.0
Width of proboscis 0.46–0.53?0.7350.435–0.5550.10.237–0.7
Length of proboscis receptacle0.63–0.74??0.750–0.9200.75?
Width of proboscis receptacle0.23–0.31???0.18–0.2?
Length of trunk52.92–102.79?130–200130–2415–18129–136
Width of trunk0.79–1.13?1–2.51.5–2.00.8–0.91–1.6
Length of small rootless spines0.07?0.0480.050.0150.02–0.06
Length of lemnisci 13.23?2.5955.48–6.803.6–41.75–3.27
Size of eggs0.064 × 0.036?0.115 × 0.0640.079–0.085 × 0.049–0.054?0.04–0.06 × 0.04
Male measurements (mm)
Length of proboscis 0.45–0.651.131–1.51.6951.45–1.72 ?0.189–1.0
Width of proboscis 0.30–0.550.660.7350.435–0.555 ?0.237–0.7
Length of proboscis receptacle0.48–0.64 ? ?0.750–0.920 ? ?
Width of proboscis receptacle0.21–0.32 ? ? ? ? ?
Length of trunk14.80–45.2916–5835–6046–75 ?22–36
Width of trunk0.53–0.991–1.70.75–1.151.4–1.92 ?0.78–1.58
Length of small rootless spines0.07 ?0.0480.05 ?0.02–0.06
Length of lemnisci 8.02 to 20.3082.5955.48–6.80 ?1.75–3.27
Size of anterior testis1.63–2.71 x 0.26–0.320.7–0.1905.752–6.045 x 0.750–0.9001.98–3.0 x 0.56–0.96 ?2.0–5.6 x 0.395–0.474
Size of posterior testis1.61–2.66 x 0.26–0.39 ? ? ? ? ?

Species

There are six valid species in the genus Gigantorhynchus, [3] [7] although one species out of the six, G. pesteri, appears to be incorrectly assigned. [2]

G. echinodiscus is a tropical parasite of anteaters including the giant anteater (Myrmecophaga tridactyla), the southern tamandua (Tamandua tetradactyla) and the silky anteater (Cyclopes didactylus). [2] It has been found in Brazil, [2] Venezuela, [9] Panama, [10] and Trinidad Island. [11] Intermediate hosts include two species of termites from Brazil ( Labiotermes emersoni and Orthognathotermes heberi ). [12] It is the first species to be described in the genus Gigantorhynchus and is the type species. [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 first row has six hooks measuring between 0.16 and 0.23 mm from the tip of the hook to the root. The second row has twelve hooks in pairs which are smaller than first row measuring between 0.18 and 0.19 mm from the tip of the hook to the root. 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. The lemnisci reach the middle of the trunk and are sometimes bent back on themselves. Other traits include a lateral papilla at the base of the proboscis, a small region (2.24 to 3.21 mm long) after the proboscis with no segmentation, a ringed with no complete segmentation, large testes, eight cement glands in pairs occupying a region measuring between 0.98 and 2.13 mm long and between 0.45 and 0.76  mm wide, and a non-segmented region in the posterior end of the body. [2]

The male has two ellipsoid testes that are narrow and in tandem. The posterior end after the anterior testes without a segmented region measures between 5.45 and 8.53 mm. In the female, the gonopore is subterminal and the vagina has a sinuous lateral region shaped like a guitar. The genital pore including the vagina, uterus, and uterine bell (a funnel like opening continuous with the uterus) is between 0.69 and 0.97 mm long. The eggs contain three membranes. [2]

G. lopezneyrai has been found parasitizing the Southern tamandua (Tamandua tetradactyla) in Venezuela. [2] The trunk is slightly segmented and no female measurements were taken in its original description. There are twelve hooks on the proboscis (4 in the first circle each around 0.235 mm long, and 8 in the second circle each around 0.106 mm long). The eight cement glands are organized in pairs. [2] Amato (2014) raised doubts about the validity of this species suggesting that the hook number and arrangement is an incorrect observation that needs to be revisited as no drawings of the proboscis showing the hook formation was published. [12] This species is named in honour of Carlos Rodríguez López-Neyra de Gorgot, a Spanish parasitologist. [9]

G. lutzi has been found parasitising a Bare-tailed woolly opossum (Caluromys philander) in Pará, Brazil [2] and infesting the small intestine of the Common opossum (Didelphis marsupialis) in Huánuco, Peru. [14] It was the second species in the genus Gigantorhynchus to be described. The body is ringed with no complete segmentation. There are twelve hooks on the proboscis including six in the first circle each measuring 0.285 by 0.165 mm, and six in the second circle measuring 0.225 by 0.135 mm. The eight cement glands are organized in pairs. [2]

G. ortizi has been found infesting the intestines of the Brown four-eyed opossum (Metachirus nudicaudatus) and possibly a White-bellied slender opossum (Marmosops cf. noctivagus) both between Iquitos and Nauta in Peru. [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. Infestations ranged from 20 to 60 worms per host almost completely obstructing the intestines in several of the sampled hosts. [17] The trunk pseudosegmented [15] or slightly segmented. [2] There are twelve hooks on the proboscis (six in the first circle each measuring 0.160 by 0.10 mm, and six in the second circle measuring 0.140 by 0.09 mm). The eight cement glands are organized in groups. 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. [15]

G. pesteri was recorded from an unknown baboon species in Rhodesia (now Zimbabwe). [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. [2] The proboscis has only four hooks whereas other species in the genus have either twelve or eighteen hooks on their proboscis. [18]

G. ungriai has been found parasitizing a Southern tamandua (Tamandua tetradactyla) in Guayo, Delta Amacuro, Venezuela. The body is ringed and has a cylindrical shape with a complete segmentation consisting of a union in dorsal and ventral regions. The anterior end without segmentation measures 2 to 2.6 mm long. The retractable proboscis has eighteen hooks arranged in two circular rows. The first row has six hooks that are 0.140 to 0.2 mm long and the second row has twelve hooks that are 0.104 to 0.180 mm long. The eight cement glands occupy a space of 0.869 by 0.1896 mm. [2] [19] The female genital tract made of an ovary-uterus extends throughout the length of the body. The male genitals occupy one quarter of the length of the body and contains elliptical testicles and eight peripheral prostate glands. [2] [19] The species name was named after Carlos Díaz Ungría. [19]

Hosts

Life cycle of Acanthocephala. Acanthocephala LifeCycle lg.jpg
Life cycle of Acanthocephala.

The life cycle of an acanthocephalan consists of three stages beginning when an infective acanthor (development of an egg) is released from the intestines of the definitive host and then ingested by an arthropod, the intermediate host. Although the intermediate hosts of most Gigantorhynchus are not known, for the order Gigantorhynchida, this intermediate host is usually an insect. When the acanthor molts, the second stage called the acanthella begins. This stage involves penetrating the wall of the mesenteron or the intestine of the intermediate host and growing. The final stage is the infective cystacanth which is the larval or juvenile state of an Acanthocephalan, differing from the adult only in size and stage of sexual development. The cystacanths within the intermediate hosts are consumed by the definitive host, usually attaching to the walls of the intestines, and as adults they reproduce sexually in the intestines. The acanthor are passed in the feces of the definitive host and the cycle repeats. There are no known paratenic hosts (hosts where parasites infest but do not undergo larval development or sexual reproduction) for Gigantorhynchus. [22]

Gigantorhynchus species infest marsupials and myrmecophagids (anteaters) in Central and South America and possibly a baboon from Africa. [2] They are found in the intestines. [23] Cystacanths, the larval state of an Acanthocephalan, of G. echinodiscus were found in the hemocoels of soldier termites, the intermediate host. Termites infested with G. echinodiscus show head shape abnormalities and discolouration. Although worker termites feed directly on the feces of the definitive host (the location of the eggs of G. echinodiscus) it is not known why they are not infected with cystacanths or how they pass the eggs on to the soldiers where they develop into cystocanths. The giant anteater diet consists almost entirely of termites and the cystacanths from consumed termites mature and reproduce in the intestines of the host and the eggs are then passed in the feces. [12] Infestation of the giant anteater can cause at least partial obstructions of the intestines, severe lesions of the intestinal wall, and may lead to death. [24] There are no reported cases of any Gigantorhynchus species infesting humans in the English language medical literature. [21]

Notes

  1. ↑ "The larger varieties belong to this group/classification" (original German: "Wie der Name besagt, sind es große Formen, die hierher gehören.") [1]
  2. ↑ One value for the length of the proboscis and lemnisci, and width of proboscis in G. lutzi is reported for both sexes
  3. ↑ One range of values for the length of the proboscis and lemnisci, and width of proboscis in G. ortizi is reported for both sexes
  4. ↑ Data for G. pesteri reported from immature female specimens.
  5. ↑ One range of values for the length of the proboscis and lemnisci, and width of proboscis in G. ungriai is reported for both sexes
  6. ↑ A binomial authority in parentheses indicates that the species was originally described in a genus other than Gigantorhynchus. This species was originally named Echinorhynchus echinodiscus by Karl Moritz Diesing in 1851 but moved to Gigantorhynchus by Hamann in 1892. [3]
  7. ↑ There are no known aberrant human infections for Gigantorhynchus species. [21]

Related Research Articles

<span class="mw-page-title-main">Brown four-eyed opossum</span> Species of marsupial

The brown four-eyed opossum is a pouchless marsupial of the family Didelphidae. It is found in different forested habitats of Central and South America, from Nicaragua to Brazil and northern Argentina, including southeastern Colombia, Paraguay and eastern Peru and Bolivia, at elevations from sea level to 1,500 m (4,900 ft). It is the only recognized species in the genus Metachirus, but molecular phylogenetics studies suggest that it should probably be split into several species. Population densities are usually low, and it is uncommon in parts of Central America. A density of 25.6/km2 (66/sq mi) was reported near Manaus, Brazil. Its karyotype has 2n = 14 and FN = 24.

Archiacanthocephala is a class within the phylum of Acanthocephala. They are parasitic worms that attach themselves to the intestinal wall of terrestrial vertebrates, including humans. They are characterised by the body wall and the lemnisci, which have nuclei that divide without spindle formation, or the appearance of chromosomes, or it has a few amoebae-like giant nuclei. Typically, there are eight separate cement glands in the male, which is one of the few ways to distinguish the dorsal and ventral sides of these organisms.

Apororhynchus is a genus of small parasitic spiny-headed worms. It is the only genus in the family Apororhynchidae, which in turn is the only member of the order Apororhynchida. A lack of features commonly found in the phylum Acanthocephala suggests an evolutionary branching from the other three orders of class Archiacanthocephala; however no genetic analysis has been completed to determine the evolutionary relationship between species. The distinguishing features of this order among archiacanthocephalans is a highly enlarged proboscis which contain small hooks. The musculature around the proboscis is also structured differently in this order. This genus contains six species that are distributed globally, being collected sporadically in Hawaii, Europe, North America, South America, and Asia. These worms exclusively parasitize birds by attaching themselves around the cloaca using their hook-covered proboscis. The bird hosts are of different orders, including owls, waders, and passerines. Infestation by an Apororhynchus species may cause enteritis and anemia.

Mediorhynchus is a genus of small parasitic spiny-headed worms. Phylogenetic analysis has been conducted on two known species of Mediorhynchus and confirmed the placement along with the related genus Gigantorhynchus in the family Gigantorhynchida. The distinguishing features of this order among archiacanthocephalans is a divided proboscis. This genus contains fifty-eight species that are distributed globally. These worms exclusively parasitize birds by attaching themselves around the cloaca using their hook-covered proboscis. The bird hosts are of different orders.

<i>Moniliformis</i> Genus of worms

Moniliformis is a genus of parasitic worms in the Acanthocephala phylum.

Promoniliformis is a monotypic genus of acanthocephalans containing a single species, Promoniliformis ovocristatus, that infests tenrecs in Madagascar. The genus PromoniliformisDollfus and Golvan, 1963 is characterized by possessing two distinct kinds of proboscis hooks. There is only one species in this genus.

<span class="mw-page-title-main">Oligacanthorhynchidae</span> Order of thorny-headed worms

Oligacanthorhynchida is an order containing a single parasitic worm family, Oligacanthorhynchidae, that attach themselves to the intestinal wall of terrestrial vertebrates.

Dendronucleata is a genus of small parasitic spiny-headed worms. It is the only genus in the family Dendronucleatidae. This genus contains three species that are distributed globally, being collected in North America and Asia. The distinguishing features of this genus among Archiacanthocephalans is the presence of randomly distributed dendritically branched giant hypodermic nuclei. Dendronucleata parasitize freshwater fish and a salamander by attaching themselves in the intestines using their hook covered proboscis and adhesives secreted from cement glands.

Australiformis is a monotypic genus of acanthocephalans containing a single species, Australiformis semoni, that infests marsupials in Australia and New Guinea. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the gut wall of its host, and a long trunk. This genus resembles species in the genus Moniliformis but is characterized by a lack of spiral muscles in the outer wall of the proboscis receptacle. The proboscis is armed with 12 rows of 13 to 15 hooks which are used to attach themselves to the small or large intestines of the host. The female worms range from 95 to 197 millimetres long, virtually all of which is the trunk, and 1.75 to 3.5 millimetres wide. There is pronounced sexual dimorphism in this species as females are around twice the size of the males whose trunks range from 46 to 80 millimetres long and 2 millimetres (0.079 in) wide. Infestation by A. semoni may cause debilitating inflammation of the stomach (gastritis) with granulomatous ulcers.

Heptamegacanthus is a monotypic genus of acanthocephalans. It contains a single species, Heptamegacanthus niekerki, parasite of the giant golden mole found in South Africa. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the rectal wall of its host, and a short, wide body. The proboscis is armed with 40 to 45 hooks that are not radially symmetrical, with seven large anterior hooks. The worms are about 4 millimetres (0.16 in) long and 2 millimetres (0.079 in) wide.

Paraprosthenorchis is a monotypic genus of acanthocephalans. It contains a single species, Paraprosthenorchis ornatus, which infests the Chinese pangolin in Vietnam.

<i>Pachysentis</i> Genus of worms

Pachysentis is a genus in Acanthocephala that parasitize primates and carnivorans. They are distributed across Africa, the Middle East, and the Americas. Pachysentis species attach themselves to the inner lining of the gastrointestinal tract of their hosts 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 the Egyptian cobra, and an adult stage where cystacanths mature in the intestines of the host. This genus appears identical to the closely related Oncicola apart from a greater number of hooks on the proboscis. There are eleven species assigned to this genus, although P. septemserialis is of uncertain taxonomic status. The female worms range from 12 millimetres (0.47 in) long and 1.6 millimetres (0.063 in) wide in P. lauroi to 50 millimetres (2.0 in) long and 4 millimetres (0.16 in) wide in P. dollfusi. Virtually all of the length is the trunk, with a short proboscis. There is pronounced sexual dimorphism in this species as females are around twice the size of the males.

<i>Oncicola</i> Genus of worms

Oncicola is a genus of parasitic worms belonging to the family Oligacanthorhynchidae. Oncicola belongs to the phylum Acanthocephalans that include many thorny-headed worms. This family contains 12 genera including the genus Oncicola. Oncicola is a part of the phylum Acanthocephalans that include many thorny-headed worms. The name comes from the prefix onc- meaning “barbed” and -cola meaning “to inhabit” in Latin. It was named and discovered in 1916 by Travassos. These worms are defined by their parasitic nature which involves hook structures found at their front end.

<i>Macracanthorhynchus</i> Genus of thorny-headed worms

Macracanthorhynchus, also known as the giant thorny-headed worm of swine, is a member of the Oligacanthorhynchidae which contains four species.

Neoncicola is a genus of parasitic worms containing nine species and belongs to the family Oligacanthorhynchidae.

Oligacanthorhynchus is a genus of parasitic worms belonging to the family Oligacanthorhynchidae.

Pararaosentis is a monotypic genus of acanthocephalans containing a single species, Pararaosentis golvani.

Raosentis is a genus of Acanthocephala that parasitize the intestine of fish.

Intraproboscis is a monotypic genus of acanthocephalans that infest African black-bellied pangolin in the Central African Republic. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the gut wall of its host, and a long trunk. It contains a single species, Intraproboscis sanghae. This genus resembles species in the genus Mediorhynchus but is characterized by infesting a mammal instead of birds, and having a simple proboscis receptacle that is completely suspended within the proboscis, the passage of the retractor muscles through the receptacle into the body cavity posteriorly, absence of neck, presence of a parareceptacle structure, and a uterine vesicle. The proboscis is armed with 34–36 rows of 6 to 7 hooks anteriorly and 15–17 spinelike hooks posteriorly which are used to attach themselves to the intestines of the host. The female worms are up to 180 millimetres long, virtually all of which is the trunk, and 2 millimetres wide.

Mayarhynchus is a monotypic genus of acanthocephalans containing a single species, Mayarhynchus karlae, that infests animals.

References

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  13. ↑ Machado Filho, D. A. (1941). "Sobre alguns acantocéfalos provenientes do estado de Mato Grosso" [About some acanthocephalans from the state of Mato Grosso]. Revista Brasileira de Biologia (in Portuguese). 1 (1): 57–61.
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  18. 1 2 3 Tadros, G. (1966). "On Gigantorhynchus pesteri n. sp from a Baboon". Journal of Helminthology. 40 (1–2): 181–186. doi:10.1017/S0022149X00034180. PMID   6006728. S2CID   45378063.
  19. 1 2 3 4 Antonio, H (1958). "Descripción de una nueva especie del género Gigantorhynchus Hamann, 1892 (Acanthocephala)" [Description of a new species of the genus Gigantorhynchus Hamann, 1892]. Acta Biologica Venezuelica (in Spanish). 2 (24): 291–298.
  20. ↑ CDC’s Division of Parasitic Diseases and Malaria (11 April 2019). "Acanthocephaliasis". www.cdc.gov. Center for Disease Control . Retrieved 17 July 2023.
  21. 1 2 Mathison, BA; et al. (2021). "Human Acanthocephaliasis: a Thorn in the Side of Parasite Diagnostics". J Clin Microbiol. 59 (11): e02691-20. doi:10.1128/JCM.02691-20. PMC   8525584 . PMID   34076470.
  22. ↑ Schmidt, G.D. (1985). "Development and life cycles". In Crompton, D.W.T.; Nickol, B.B. (eds.). Biology of the Acanthocephala (PDF). Cambridge: Cambridge Univ. Press. pp. 273–305.
  23. ↑ Tantaleán, Manuel; Sánchez, Lidia; Gómez, Luis; Huiza, Alina (2005). "Acanthocephalan from Peru". Revista peruana de biología (in Spanish). 12 (1): 83–92. doi: 10.15381/rpb.v12i1.2361 . Retrieved 25 January 2020.
  24. ↑ Bomon, M. (2018). Management of gastrointestinal parasites in wildlife rehabilitation centers in Brazil (PDF) (Doctoral dissertation). Universidade de Lisboa, Faculdade de Medicina Veterinária. pp. 70–71. Retrieved 25 May 2020.

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