What Are The Main Characteristics Of Animals That Belong To The Phylum Nematoda? Scholarly Article

The organisms belonging to the phylum Nematoda are also known as "roundworms". There are 28000 species of Nematoda identified till date. They are unsegmented vermiform animals. The epidermis has dorsal and ventral nerve cords.

Nematoda

The Nematodes present in the soil feed on the bacteria, fungi, and other nematodes, and play an important part in nutrient recycling. They also attack the insects and command the pests. Still, they cause astringent damage to plants. They feed on the institute roots and reduce the nutrient uptake and stress tolerance of the plant.

A spadeful of soil contains numerous Nematodes. They cause diseases such as Ascariasis, Trichuriasis, Hookworm, Enterobiasis, Filariasis, and Angiostrongyliasis in humans.

They are characterized and categorized in the post-obit ways.

Characteristics of Nematoda

Following are the important characteristics of Nematoda:

Their body is bilaterally symmetrical and triploblastic.
They are cylindrical in shape.
They showroom tissue level system.
Their body has a cavity or pseudocoelom.
The alimentary canal is distinct, with the mouth and the anus.
They are sexually dimorphic.
They are devoid of the circulatory system and respiratory system.
They are gratuitous-living or parasitic.
Parasitic nematodes crusade diseases in the host.
Fertilization is internal and reproduction is sexual.
Their cuticle moults periodically.
The epidermis is synctical and contains dorsal or ventral nervus cords.
The body-wall muscles are longitudinal.
They possess amoeboid sperm cells.
They consist of chemosensory organs called aphids situated on the lips.

Classification of Nematodes

Nematodes are classified into the following classes:

Phasmidia or Secernentea

These are mostly parasitic.
Caudal glands are absent.
Unicellular, pouch-like sense organs called plasmids are present.
The excretory organization has paired lateral canals.
Eg., Ascaris, Enterobius

The class Phasmidia is divided into the following orders:

Rhabditida

They have smoothen and ringed cuticle.
There is a posterior lobe at the pharynx.
They are costless-living and parasitic.
Males have copulatory spicules.
Eg., Rhabditis

Strongylida

They are vertebrate parasites devoid of lips.
The pharynx has no bulb.
They have a well-developed buccal capsule.
They possess a true copulatory bursa.
For eg., Strongylus

Oxyurida

They can be small or moderate in size.
Males have copulatory spicules.
Caudal alae are present.
They can be invertebrates or vertebrates.
The oral fissure consists of iii-4 elementary lips.
For eg., Oxyuris

Ascaridida

These are oviparous, large stout nematodes living as parasites in the intestine of the vertebrates.
The pharynx may or may not contain a posterior bulb.
Mouth possess three prominent lips.
There is no buccal capsule.
For eg., Ascaris

Spirurida

These are thread-like organisms that vary in size from moderate to large.
The pharynx is devoid of bulb.
The females are larger than males and can exist oviparous or viviparous.
The oral fissure contains 2 prominent lips.
For eg., Spirura

Trichuroida

These are ordinarily known every bit whip-worms.
They possess a slender pharynx.
The oral fissure is devoid of lips.
For eg., Trichuris

Camallanida

These are oviparous, thread-like organisms.
The males have no bursa.
The bursa of adult females is degenerated.
For eg., Camallanus

Aphasmidia or Adenophorea

They are complimentary-living organisms.
The excretory organization has no lateral canals.
Caudal glands are present.
Phasmids are absent.
Eg., Capillaria, Trichinella

The course Aphasmidia or adenophorea is divided into the following orders:

Enoplida

They are more often than not marine.
The cuticle contains bristles.
These are Cyanthiform amphids.
For eg., Anticoma

Dorylaimida

The cuticle is smooth without whatsoever bristles.
These are mostly terrestrial.
The buccal crenel consists of a protrusible spear.
It consists of 6-x labial papillae.
For eg., Trichodoris

Mermithida

The cuticle is smooth.
Amphids are reduced.
In the larval stage, they live every bit parasites, whereas, the adult stage is free-living.
For eg., Mermis, Agamermis

Chromedorida

The cuticle is smooth or ringed.
The cuticle is devoid of any beard.
At that place is a posterior bulb at the pharynx.
They are free-living or marine.
For eg., Paracanthonchus

Desmoscolecida

The cuticle is ringed with prominent bristles.
There are four sensory bristles at the anterior end.
They are marine or free-living.
For eg., Desmoscolex

Monohysterida

The cuticle is smooth, ringed and contains bristles.
They possess circular amphids.
They can be marine, freshwater, or terrestrial.
For eg., Monohystera

Araeolaimida

The cuticle is smooth and might or might not contain bristles.
The amphids are spiral.
They possess labial papillae.
For eg., Plectus

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