Enoplea (enopleans) is a class, which with the classes

Secernentea Secernentea was a 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 This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based o ...

Tree of Life Web Project The Tree of Life Web Project 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 site ...

(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 ...

make up the phylum

Nematoda The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

in current

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

. 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) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to ...

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 nematod ...

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 (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. ...

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 excreto ...

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 (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

of phylum Nematoda suggests three distinct basal

clades A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, the dorylaims, enoplids and

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 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. *Subclass Enoplia **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 *Subclass Dorylaimia **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 **Order Mononchida **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 **Order Marimermithida

Ecology

Several orders of enopleans are mainly freshwater animals, and several include marine species. Many enopleans are

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

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 a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

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'' type. 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 domestic pig (''Sus domesticus''). It is the most commonly consumed meat worldwide, with evidence of pig husbandry dating back to 5000 BCE. Pork is eaten both freshly cooked and preserved; ...

, '' Haycocknema perplexum'' which can be life-threatening to humans, and whipworms (genus ''Trichuris''), which are parasites of mammals, including cats, dogs, and humans.

References

Bibliography

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