''Triaspiron'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus of

acanthocephala Acanthocephala ( Greek , ' 'thorn' + , ' 'head') is a group of parasitic worms known as acanthocephalans, thorny-headed worms, or spiny-headed worms, characterized by the presence of an eversible proboscis, armed with spines, which it uses t ...

ns (thorny-headed or spiny-headed

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

worms) containing a single species, ''Triaspiron aphanii''.

Taxonomy and description

''T. aphanii'' resembles '' Raosentis'' Datta, 1947 by having a small spindle shaped trunk. ''Triaspiron'' differs from ''Raosentis'' in the shape of the proboscis (cylindrical not globular), proboscis armed with 16 hooks divided into three circles (not four circles), and a total of between 26 and 30 hooks in all. ''Triaspiron'' also differs by the spines on the trunk: there are two separate regions of spines in the anterior region arranged in up to 40 circular rows, not a single field with 9 to 17 rows of spines. ''Triaspiron'' also resembles the genus '' Acanthogyrus'' Thapar, 1927, by having three circles of hooks on the proboscis. ''Triaspiron'' differs from ''Acanthogyrus'' in having fewer proboscis hooks, 16 compared with between 18 and 24, that are arranged in three circles, one anterior circle followed by an unarmed region followed by two posteriorly circles instead of three circles of hooks evenly spaced. It also has two fields of trunk spines instead of one. ''Triaspiron aphanii'' is the type species. The

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

does not indicate that any

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 published on ''Triaspiron'' that would confirm its position as a unique order in the family

Quadrigyridae Quadrigyridae is the only family within Gyracanthocephala, an order of parasitic worms of class Eoacanthocephala. This family contains two subfamilies, ten genera and about 92 species. Species Species in ''Quadrigyridae'' are divided into two su ...

Distribution

The distribution of ''T. aphanii'' is determined by that of its hosts, which are found in Kirkgöz Springs, Antalya, Turkey.

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

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 ...

. Although the intermediate hosts of ''Triaspiron'' are not known. 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 The midgut is the portion of the human embryo from which almost all of the small intestine and approximately half of the large intestine develop. After it bends around the superior mesenteric artery, it is called the "midgut loop". It comprises t ...

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 is 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 ''Triaspiron''. ''Triaspiron'' was found to infest 90% of a sample of

Iridescent toothcarp The iridescent toothcarp or pearl-spotted killifish(''Paraphanius mento'') is a species of killifish in the family Aphaniidae. It can be found in Western Asia (Iraq, Israel, Jordan, Lebanon, Palestine, Syria and Turkey). It occurs in a wide range ...

(''Aphanius mento''). There are no reported cases of any ''Triaspiron'' species infesting humans in the English language medical literature.

Notes

References

{{Taxonbar, from1=Q61715565, from2=Q61716488 Eoacanthocephala Monotypic protostome genera Parasitic animals of mammals Taxa described in 2012