| Macracanthorhynchus | |
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| Adult Macracanthorhynchus hirudinaceus | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Acanthocephala |
| Class: | Archiacanthocephala |
| Order: | Oligacanthorhynchida |
| Family: | Oligacanthorhynchidae |
| Genus: | Macracanthorhynchus Trevassos, 1917 |
| Species | |
Macracanthorhynchus, also known as the giant thorny-headed worm of swine, is a member of the Oligacanthorhynchidae which contains four species.
Phylogenetic analysis has been conducted on at least one of the four species in the genus, M. ingens, and confirms that this species beongs to the family Oligacanthorhynchidae. [1] The type species is M. hirudinaceus. [2]
| 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). [3] [4] Amin et al. (2022) used the 18S rDNA gene and ITS1-5.8-ITS2 region of ribosomal RNA comparisons to add P. canicola phylogenetically to the family Oligacanthorhynchidae. [1] |
Macracanthorhynchus consists of a proboscis covered in hooks and a long trunk.
There are four species in the genus Macracanthorhynchus. [2] [5] [lower-alpha 1]
The encysted larvae of M. catulinus beetle Adesmia gebleri from the Kara Kum region are 6.32 mm long and have a proboscis 0.57 mm long with 12 longitudinal rows of three hooks each. The size of the hooks varies from 0.25 mm to 0.11 mm. Small vertebrates, such as the badger and weasel may be reservoir hosts. [6] Pre-acanthellae and acanthellae of M. catulinus were found infesting Tentyria tessulata Azerbeijan, and acanthellae were found in the paratenic hosts, Sheltopusik (Ophisaurus apodus), Coluber jugularis , Agama caucasica , Eumeces schneideri , Eremias pleskei , Lacerta strigata and the Marsh frog (Pelophylax ridibundus). [7]
M. hirudinaceus is a parasite which lives in the intestines of pigs and other suids, and very occasionally in humans or dogs. It causes enteritis, gastritis or peritonitis. Its life cycle includes beetles of the genus Melolontha as intermediate hosts.[ citation needed ] This species has many synonyms which include: Echinorhynchus gigas (Block, 1782), Macracanthorhynchus gigas (Block, 1782), [8] Echinorhynchus hirundinacea (Palas, 1781), Gigantorhynchus hirundinaceus (Pallas, 1781), Gigantorhynchus gigas (Block, 1782), [9] Hormorhynchus gigas (Block, 1782), Taenia haeruca (Pallas, 1776), and Taenia hirundinaceus (Pallas, 1781) [10] The complete mitochondrial genome of M. hirudinaceus has been sequenced. [11] The eggs have 4 membranes are 98 um long and have an elongation ratio of 1.85. [12]
The eggs have three membranes, are 94 um long and have an elongation ratio of 1.66. [12] It parasitizes the raccoon (Procyon lotor) in the United States. [4]
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. The intermediate hosts of Macracanthorhynchus include beetles. 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 Macracanthorhynchus. [14]
Gigantorhynchus is a genus of Acanthocephala 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.
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.
Oligacanthorhynchida is an order containing a single parasitic worm family, Oligacanthorhynchidae, that attach themselves to the intestinal wall of terrestrial vertebrates.
Acanthocephaloides is a genus of parasitic worms belonging to the family Arhythmacanthidae.
Euzetacanthus is a genus in Acanthocephala.
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.
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.
Multisentis is a monotypic genus of acanthocephalans. It contains a single species, Multisentis myrmecobius , parasite of the numbat from which it derives its species name. It was found in south-western Australia.
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.
Floridosentis is a genus in Acanthocephala.
Cathayacanthus is a genus in Acanthocephala.
Cavisoma is a monotypic genus of acanthocephalans containing a single species, Cavisoma magnum, that infests animals.
Caballerorhynchus is a monotypic genus of acanthocephalans containing a single species, Caballerorhynchus lamothei, that infests animals.
Filisoma is a genus in Acanthocephala.
Nephridiacanthus is a genus of parasitic worms belonging to the family Oligacanthorhynchidae.
Dispiron is a genus in Acanthocephala belonging to the family Neoechinorhynchidae.
Octospiniferoides is a genus in Acanthocephala belonging to the family Neoechinorhynchidae.
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.
Paralongicollum is a genus in Acanthocephala, the thorny-headed worms, also known as spiny-headed worms.
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