Enoplea (enopleans) is a

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

, which with the classes

Secernentea Secernentea was a class (biology), class of nematodes in the Classical Phylogeny System (Chitwood, 1958) and is no longer in use. This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assi ...

Tree of Life Web Project The Tree of Life Web Project (ToL) is an Internet project providing information about the diversity and phylogeny of life on Earth. This collaborative peer reviewed project began in 1995, and is written by biologists from around the world. The s ...

(ToL) (2002)
Nematoda
Version of January 1, 2002. Retrieved November 2, 2008. and

Chromadorea The Chromadorea are a class of the roundworm phylum, Nematoda. They contain a single subclass (Chromadoria) and several orders. With such a redundant arrangement, the Chromadoria are liable to be divided if the orders are found to form several c ...

make up the

phylum In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead ...

Nematoda The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitism, parasitic. Parasitic ...

in current

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

. The Enoplea are considered to be a more ancestral group than the

, and researchers have referred to its members as the "ancestrally diverged nematodes", compared to the "more recently diverged nematodes" of Chromadorea.

Description

The Enoplea are distinguished from the Chromadorea by a number of characteristics. The enoplean

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

is cylindrical or "bottle-shaped", compared to the bulbous chromadorean esophagus. Enopleans have pocket-like

amphid Amphids (Greek: ''amphi'', around, double) are innervated invaginations of cuticle in nematodes. They are usually found in the anterior (head) region of the animal, at the base of the lips. Amphids are the principal olfactosensory organs of nemato ...

s, while chromadoreans have amphids shaped like slits, pores, coils, or spirals. An enoplean is smooth or marked with fine lines, while a chromadorean may have rings, projections, or

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e. The enoplean

excretory system The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excret ...

is simple, sometimes made up of a single cell, while chromadoreans have more complex, tubular systems, sometimes with glands.Class Enoplea.
Nemaplex: Nematode-Plant Expert Information System. University of California, Davis. Version October 9, 2012.

Taxonomy

Phylogenetic analysis 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 data ...

of phylum Nematoda suggests three distinct basal

clades In biology, a clade (), also known as a monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy ...

, the

dorylaims Dorylaimia is a subclass of nematodes. Description In general, members of subclass Dorylaimia exhibit a great diversity of terrestrial and freshwater species, most of which are large predators or omnivorous free-living species. Some are plant ...

enoplids Enoplida is an order (biology), order of nematodes. It is one of two orders in Enoplia, which is one of two subclasses in Class Enoplea.chromadorids The Chromadorea are a class of the roundworm phylum, Nematoda. They contain a single subclass (Chromadoria) and several orders. With such a redundant arrangement, the Chromadoria are liable to be divided if the orders are found to form several c ...

. These represent Clades I, II and C+S of Blaxter (1998). Of these, the first two appear to have

sister clade In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

status, allowing resolution into two classes, Enoplea and Chromadorea, and division of the former into two subclasses corresponding to Clades I and II respectively, the Enoplia and Dorylaimia.

Subdivision

Two subclasses are divided into

orders Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * H ...

. *Subclass

Enoplia The Enoplia are a subclass of nematodes in the class Enoplea. Description Enoplians are characterized by amphids shaped like ovals, stirrups, or pouches. Their bodies are smooth, without rings or lines. The esophagus is cylindrical and glandu ...

**Order

Enoplida Enoplida is an order of nematodes. It is one of two orders in Enoplia, which is one of two subclasses in Class Enoplea.

**Order Trefusiida **Order

Triplonchida Triplonchida is an order of terrestrial nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorg ...

*Subclass

Dorylaimia Dorylaimia is a subclass of nematodes. Description In general, members of subclass Dorylaimia exhibit a great diversity of terrestrial and freshwater species, most of which are large predators or omnivorous free-living species. Some are plant ...

**Order

Dorylaimida Dorylaimida (dorylaims) is a diverse order of nematodes with both soil and freshwater species. Taxonomy History The order originated with the description of '' Dorylaimus stagnalis'' by Dujardin in 1845, and in 1876 De MAn proposed the fam ...

**Order

Mermithida Mermithida is an order of nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but ma ...

**Order

Mononchida Mononchida is an order of nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but m ...

**Order Dioctophymatida **Order

Trichinellida The Trichocephalida (Trichinellida or Trichurida in other classifications) is an order of parasitic nematodes. Taxonomy The order Trichocephalida includes, according to modern classifications, the single suborder Trichinellina Hodda, 2007, which ...

**Order Isolaimida **Order

Muspiceida Muspiceida is an order of nematodes belonging to the class Enoplea Enoplea (enopleans) is a Class (biology), class, which with the classes SecernenteaTree of Life Web Project (ToL) (2002)Nematoda Version of January 1, 2002. Retrieved November ...

**Order Marimermithida

Ecology

Several orders of enopleans are mainly

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

animals, and several include marine species. Many enopleans are

parasites 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 en ...

of plants and animals, including humans. The orders Triplonchida and Dorylaimida include plant-parasitic nematodes that are vectors of plant pathogens. The orders Mermithida and Marimermithida include parasites of

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s. The orders Dioctophymatida, Trichinellida, and Muspiceida include parasites of vertebrates such as birds and mammals. Examples are ''

Trichinella spiralis ''Trichinella spiralis'' is a viviparous nematode parasite, occurring in rodents, pigs, bears, hyenas and humans, and is responsible for the disease trichinosis. It is sometimes referred to as the "pork worm" due to it being typically encount ...

'', a nematode known for causing

trichinosis Trichinosis, also known as trichinellosis, is a parasitic disease caused by roundworms of the '' Trichinella'' genus. During the initial infection, invasion of the intestines can result in diarrhea, abdominal pain, and vomiting. Migration of ...

in humans who consume it in undercooked

pork Pork is the culinary name for the meat of the pig (''Sus domesticus''). It is the most commonly consumed meat worldwide, with evidence of pig animal husbandry, husbandry dating back to 8000–9000 BCE. Pork is eaten both freshly cooke ...

, '' Haycocknema perplexum'' which can be life-threatening to humans, and

whipworms ''Trichuris trichiura, Trichocephalus trichiuris'' or whipworm, is a parasitic roundworm (a type of helminth) that causes trichuriasis (a type of helminthiasis which is one of the neglected tropical diseases) when it infects a human large inte ...

(genus ''Trichuris''), which are parasites of mammals, including cats, dogs, and humans.

References

Bibliography

* * * {{Taxonbar, from=Q1933805 Ecdysozoa classes