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

Taxonomy

Phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

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. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is '' M. hirudinaceus''.

Description

''Macracanthorhynchus '' consists of a proboscis covered in hooks and a long trunk.

Species

There are four species in the genus Macracanthorhynchus. *''Macracanthorhynchus catulinus'' Kostylev, 1927 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. 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 The marsh frog (''Pelophylax ridibundus'') is a species of water frog native to Europe and parts of western Asia. Description The marsh frog is the largest type of frog in most of its range, with males growing to a size around 100 mm (3.9 ...

(''Pelophylax ridibundus''). *''Macracanthorhynchus erinacei'' Dollfus, 1953 *''Macracanthorhynchus hirudinaceus'' (Pallas, 1781) ''M. hirudinaceus'' is a

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

which lives in the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

s of

pig The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities cons ...

s and other suids, and very occasionally in

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s or

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...

s. It causes

enteritis Enteritis is inflammation of the small intestine. It is most commonly caused by food or drink contaminated with pathogenic microbes,Dugdale, David C., IIII, and George F Longretc"Enteritis" MedlinePlus Medical Encyclopedia, 18 October 2008. Acces ...

gastritis Gastritis is the inflammation of the lining of the stomach. It may occur as a short episode or may be of a long duration. There may be no symptoms but, when symptoms are present, the most common is upper abdominal pain (see dyspepsia). Othe ...

peritonitis Peritonitis is inflammation of the localized or generalized peritoneum, the lining of the inner wall of the abdomen and covering of the abdominal organs. Symptoms may include severe pain, swelling of the abdomen, fever, or weight loss. One pa ...

. Its life cycle includes

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s of the genus '' Melolontha'' as

intermediate host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

s. This species has many synonyms which include: ''Echinorhynchus gigas'' (Block, 1782), ''Macracanthorhynchus gigas'' (Block, 1782), ''Echinorhynchus hirundinacea'' (Palas, 1781), ''Gigantorhynchus hirundinaceus'' (Pallas, 1781), ''Gigantorhynchus gigas'' (Block, 1782), ''Hormorhynchus gigas'' (Block, 1782), ''Taenia haeruca'' (Pallas, 1776), and ''Taenia hirundinaceus'' (Pallas, 1781) The complete

mitochondrial genome Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

of ''M. hirudinaceus'' has been sequenced. The eggs have 4 membranes are 98 um long and have an elongation ratio of 1.85.Pfenning, A. C. (2017). Egg morphology, dispersal, and transmission in acanthocephalan parasites: integrating phylogenetic and ecological approaches.Url=https://via.library.depaul.edu/cgi/viewcontent.cgi?article=1273&context=csh_etd *''Macracanthorhynchus ingens'' ( Linstow, 1879) The eggs have three membranes, are 94 um long and have an elongation ratio of 1.66. It parasitizes the

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

(''Procyon lotor'') in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Hosts

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 In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

and then ingested by an arthropod, the

. The intermediate hosts of ''Macracanthorhynchus'' include beetles. When the acanthor

molt In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at ...

s, 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

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

l 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 Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...

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''. File:Raccoon in Central Park (35264).jpg, alt=Racoon in a park, The racoon is a host of ''M. ingens''

Notes

References

Archiacanthocephala Acanthocephala genera {{acanthocephalan-stub