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Myriapods, their characteristics, anatomy, habitat, diet, and reproduction make the researchers understand the species in a better way and they can easily differentiate the organisms from others. Arthropods comprise millipedes, centipedes, pauropods, and symphylans are myriapods. Although each of these sub-groups is considered to be monophyletic, whether the entire group is monophyletic is less clear. Illacme plenipes, one specimen of a rare millipede found in central California, had 750 legs, the most of any recorded species, but mostly, myriapods have between 20 and 400 legs.

Myriapods are notable for including the ancient land animal known, Pneumodesmus newmani, a millipede that lived during the Middle Silurian in Scotland 428 million years ago.  It was a land animal, due to the existence of spiracles, small holes used for breathing air.

Mike Newman, who was finding fossils as a hobby, found the 1-cm (0.4 in) fossil sample. A spider-like fossil which was also identified in Scotland and also was discovered to be 20 million years older than the previously oldest known land mammal. Since, Scotland, throughout its history has been thoroughly survived by glaciers, it has left older structures completely exposed and ready for fossil hunting.

Centipedes are generally carnivorous (which is shown in their fearful appearance) of the myriapods, while millipedes mainly eat detritus, while other species eat small arthropods. Symphylans and pauropods are little soil arthropods that look similar to centipedes outwardly and move between soil grains quickly.

In wet forests, all myriapods are widespread, where they play an important role in breaking down plant material, producing nutrient-rich detritus for bacteria to break down even further. You’ll probably see hundreds of myriapods crawling out if you pick a wood in a damp forest.

What are the Characteristics of Myriapods?

Myriapods have extended segmented body with more paired, jointed legs. Formerly, they were sorted as a class consisting of centipedes and millipedes. Its multiple legs are the signature feature of myriapods, but many of them have other common features, such as repugnatory glands, which contain an unpleasant liquid used to discourage predators. Benzoquinones, which can burn the human skin, are also present in this fluid.

Anatomy of Myriapods

Anatomy of Myriapods-Ckrokill

A subphylum of arthropods including millipedes, centipedes, and others is Myriapoda. Over 13,000 species are included in the group, all of which are inland. Though their name indicates that they have countless (10,000) legs, myriapods vary from having less than ten legs to having over 750 legs.

Myriapods have legs in many cases. Each segment of the trunk usually has one pair of legs. Chilopods (centipedes) have their first pair of walking legs transformed into clawlike appendages; each pair of sections is joined together by diplopods (millipedes), resulting in two pairs of legs per segment. Some legs may indeed be transformed into gonopods in other classes, performing a reproductive role.

Having several legs requires a degree of rhythmic movement to attain good coordination. Segment and leg length specifies the fundamental gaits, which can be adjusted to support easy escape or slow soil insertion. Movement is described by a metachronal wave-like rhythm.

Structure and Classification of Myriapods

Myriapods have a single pair of antennae and plain eyes, in several cases. On the underside of the head, the mouthparts lie. The upper lip is formed by an “epistome” and labrum, and the lower lip is formed by a pair of maxils. Within the mouth, a pair of mandibles exists. Myriapods breathe similar to that of insects by spiracles that attach to a tracheal system.

There has been much doubt as to which group of arthropods is most closely connected to the Myriapoda. Myriapoda is the sister species to Pancrustacea, a group consisting of Crustacea and Hexapoda, under the Mandibulata hypothesis.

Hexapoda is the close, under the Atelocerata hypothesis, while Chelicerata is the nearest, under the Paradoxopoda hypothesis. While supported by a few morphological characters, this last concept is supported by a number of molecular studies.

Myriapods, Chilopoda (centipedes), Pauropoda, and Symphyla Diplopoda (millipedes) are the four classes. There are about 12,000 living organisms in total. Although it is known that each of these classes of myriapods is monophyletic, associations are less clear between them.

Habitat and Diet of Myriapods

In damp forests, myriapods are most common, where they play an important role in breaking down dying plant material, even though a few live in grasslands, dry environments, or even deserts. A very small percentage of species (found along the seashore) is littoral. They are detritivores. The main part of the diet is deadwood and leaves, splitting dead plant material into small pieces. Bacteria and microscopic fungi feed on the feces of detritivores, making them an important link in the recycling of organic matter in the soil.

Reproduction and Lifecycle of Myriapods

The females lay the eggs that were fertilized by the males. Both Centipedes and Millipedes have different sexes. Some species lay eggs in a ‘nest’ where the female protects them, others lay eggs one at a time and leave them.

Centipedes grow slowly, even before they mature, with seven or more molts occurring. The eggs and young centipedes closely resemble adults in most cases; others have just a few pairs of legs, however. Depending on the species, the young centipedes may or may not generate new body segments and legs as they molt.

Facts about Myriapods

  • Centipedes are the only arthropods that have ‘poison claws’.
  • All centipedes are predators.
  • The young millipedes only have three pairs of legs.
  • Male millipedes attract females with songs and backrubs.
  • Male millipedes have ‘sex’ legs called gonopods.

The Difference between Millipedes and Centipedes

Millipedes have a segmented, cylindrical shape. In each segment, there are two pairs of short legs. Millipedes do not have more than 750 legs, given their common name. Typically they are dark-colored. The vast majorities of these dangerous animals feed on plant material and are harmless. They survive under the leaves, the rocks, and the trunks of dying trees.

There are also segmented bodies in Centipedes, but they are thinner and have just one pair of legs per segment. Centipedes have long, powerful legs that allow them to move around fast. The number of legs differs widely, from 30 to over 350. Centipedes, like millipedes, prefer humid places and are found commonly in gardens. The quickest centipedes’ species are those with the lowest number of legs.

Centipedes are strong predators with venom-filled hooks called forcipula that they use to immobilize their prey. These adapted legs, located under the body, cover the mouthparts. To paralyze the centipede’s prey, venom flows out of the tip of the hook. The venom has many active ingredients, including histamine and acetylcholine. There are also a variety of enzymes, some of which are responsible for the pain caused when the venom is inserted.

The Taxonomic groups of Myriapods


Though centipedes normally don’t get longer than about 2 inches, they can reach up to 12 inches in length in places where there is plenty of warmth and moist. They have flat bodies made up of a series of sections, with two long antennas topping the rounded heads.

On close examination, it becomes clear that the antennas are made up of a series of small segments, larger next to the head of the creature and slowly growing smaller towards the end. Centipedes are brown, reddish-brown or grey in general, although the color varies by species.

Centipedes have one leg pair per section of the body. The pair right behind the head is specialized and act as fangs to bite its prey. It also specializes in the last pair of legs and is longer than the rest, allowing the centipede to capture and retain its prey while spraying venom. On both sides, the legs of the centipede stick out of its body, making it easy to differentiate from the millipede, which has all its legs behind it.

Even if people do not allow centipedes into their houses, this arthropod is beneficial since it eats many of the bugs that could otherwise damage the house or its belongings. Centipedes use their venom to paralyze the prey such as insects and spiders.   In one region, either your home or garden, if a large number of centipedes are found, chances are that they are there because of plenty of food. Removing the prey would reduce the population of the centipede.

In damp, cooler regions, such as under rocks and logs or in cracks along walls or foundations, Centipedes live. Where it is dry, they cannot exist and can shift into cold basements, hiding under boxes or in gaps between the slabs. In kitchens and toilets, Centipedes will also run for cover to take full advantage of the damp there. They are often active at night and hardly ever seen in the daytime, but, sometimes they will go out to hunt.



The large black creatures with a million short legs that you see moving through the windows of your bedroom and that, when disturbed, roll into a tight ball. They’re not going to bite you, but they can release a smelly fluid that could irritate your skin or eyes. They can be a threat in huge numbers, even though they’re not dangerous to your family.

These creatures belong to the family of Arthropods and look similar to thousand-legged species but, they are invertebrates with an exoskeleton, a segmented body, and jointed limbs. Some of the earliest animals to live on land are Millipedes. Prehistoric evidence suggests that, at six feet long and one and a half feet high, a millipede-like organism was one of the first and largest invertebrates to crawl on land. One unique fossil was traced back 420 million years and was called Pnueumodesmus newmani.

Millipedes are small recyclers in nature. They are detritivores, which means they feed on plants and animals that are dead.

The millipedes recycle the nutrients back into the soil at a much quicker pace than plants and animals rotting naturally and range in size from one-quarter to even 15 inches long, play a significant role in breaking down the waste of nature.

They prefer damp places because they need moisture to live. That’s why, if you see them inside your home, you’ll mostly see them around your crawl spaces, damp basements, storerooms, and sliding glass doors or windows and they also favor outdoors, making their habitats under mulch, compost, stones, and leaves.

Even though the natural home of a millipede is not in your home, after long periods of rain or drought, you will find them in the spring and fall. But for long, they won’t be there. Since millipedes need such a greater amount of moisture, they typically die within a home within one to two days. So, you can wait for a while and clean up the remains if you have an infestation.

Millipedes don’t have 1,000 legs. With just three pairs of legs, a young one is born and can grow up to 200 as an adult. For each body segment, they have two pairs of legs. Since centipedes only have one pair of legs per segment, this is the main difference between millipedes and centipedes.

Millipedes protect themselves if they feel threatened, by coiling up into a spiral. This keeps their soft undersides covered. When they die, they even fold into a coil.

Centipedes and Millipedes are somewhat different, although they are similar. The bodies of Millipedes are rounder, while centipedes have a flatter shape and enlarged antennae. Often, centipedes are much faster than millipedes. The most significant distinction is that centipedes are carnivores and some creatures can bite. The bite of a centipede is very painful and health issues can be caused by its venom. If you believe that a centipede might have bitten you, contact a doctor immediately.



The smooth, white symphylene bodies are long and slender, measuring 2 to 8 millimeters (0.078 to 0.31 inches ) in length. The head is heart-shaped, separate, and has three pairs of mouthpieces. To develop a lower lip, one pair is merged together.

The sensory organs, or antennae, are long and threadlike or beadlike. There don’t have eyes. There are fourteen segments on the body. Fifteen to twenty-four soft plates coat the back of the body. The first twelve segments of the body have a pair of legs each. There are a short, strong spine and a special structure at the base of each knee.

The spine is likely to help the symphylene pass through the soil, while the sac is likely to control the body’s water and salts. There are a pair of projections in each of its body segments from which the symphylans create silk. A pair of long, responsive hair-like structures are present in the last body segment. Symphylans, except Antarctica, are present in all continents. There are around two hundred species worldwide.

In both natural and agricultural environments, the Symphylans live in the upper 3.2 foot (1 meter) layers of soil. They prefer soil that is damp but not wet.

Symphylans eat primarily roots and root structures of fungus, but most species are likely to be omnivorous or live on both plants and animals.

Symphylans are commonly found in large numbers and join in groups occasionally. In order to maintain the correct moisture levels in their climate, they move up and down in the soil. Their antennas are continuously shifting as they hunt for food and mates, but while feeding, they are kept over the body. Symphylans, especially when threatened, run quickly.

For reproduction, males and females are both necessary. On the field, males store sperm packets. The females pick up the packets of sperm in their mouths later. No study exists regarding their courtship behavior or how they might work together or communicate with each other.

Learn More About Natural Pesticides, their Types and their Benefits to the Plants

Females drop a collection of up to twenty-five white eggs. The young ones have only fewer bodies and just six to seven pairs of legs than adults. They are very idle and will add an extra segment and pair of legs each time they grow, or lose their exoskeleton or hard outer covering, till they hit adulthood with twelve pairs.

Symphylans are small, quiet creatures that are largely unknown to the public and do not bite or sting. Garden Symphylans affect plants such as pineapple, beets, potatoes, beans, and many others. In greenhouses, they are also a pest.



Some of them, like the pill bug, are pretty large; others, such as the pauropoda, are little. Small arthropods that look like centipedes and millipedes are pauropoda. Typically, they are pale in color and very thin, reaching less than 5 mm. With their segmented bodies and legs, they look identical to centipedes.

Its branched antennas are the best distinguishing feature of pauropods.  Each antenna creates two or more breaks. They live under stones in the soil, under rotting wood, and in dead leaves. Although some can’t, others can go fast. They move in intervals and change directions constantly when they move.

They develop another pair of legs each time they molt. Usually, adults have between 9 and 11 pairs of legs. They have no eyes or heart; most of them do not even have trachea! Some have mandibles that make it possible for them to bite, while others do not.

In the kingdom of Animalia, eumetozoa sub-kingdom, ecdysosoa super-phylum, arthopoda phylum, and the third class of sub-phylum Myriapoda are pauropoda.

Worldwide, 500 species have been reported so far.100 species are from North America, 19 from Tasmania, and 18 from Australia. 



Arthropleuridea is an endangered subclass of myriapod arthropods that existed just before the Early Permian during the Carboniferous Era, first appearing during the Silurian Period, and facing death due to climate change. Members are distinguished by having paranotal tergal lobes divided by a suture from the body axis and by sclerotized plates supporting the leg attachments.

The latest phylogenetic analysis, despite its specific characteristics, indicates that Arthropleuridea is included among millipedes in the Diplopoda class. Three known orders are in the subclass, each with a single genus.

Arthropleuridea is the most popular for Arthropleura (order Arthropleuridea). Arthropleurids are among the biggest arthropods to have ever existed, measuring over 2 meters in length. The absence of large terrestrial vertebrate predators and the extremely oxygenic environment likely allowed them to grow so huge. Arthropleurids existed in the damp coal swamps that were widespread at the time and might have hidden in the bushes.

Either they were herbivores or they were detritivores. In addition to their height, the legs with eight segments (as many as 30 pairs) and especially hard exoskeletons were their most distinguishing features. There is no proof of spiracles, so the animals might have used lungs or gills for respiration. As the atmosphere grew drier and the coal swamps dried out, Arthropleura would be dead.

Most Arthropleurideans are considered to be terrestrial, but terrestriality is only assumed by comparison to modern arthropods without any specific respiratory system. However, early forms seem to have been aquatic, like Eoarthropleura (order Eoarthropleurida). For this reason, some challenge Arthropleuridea’s inclusion among millipedes since no modern aquatic myriapods are known.

Related Questions

1. What are the characteristics of myriapods?

Many pairs of legs, two body sections such as head and truck, Antennae on the head, eyes, mandibles, and maxillae are the major characteristics of myriapods. Respiration occurs through a tracheal system.

2. What are some examples of myriapods?

A group of arthropods and it consists of millipedes, centipedes, pauropods, and symphylans.

3. What is the name of the group of myriapods?

About 15,000 species of myriapods are living today among humans. As their name signifies, myriapods are famous for having many legs, though the number differs broadly from species to species.

4. What is the significance of myriapods?

The important aspect of myriapods is the role they play in the ecological balance of wooded regions. In addition, their limited capability to move, their dependency on suitable humidity and habitat conditions, and their common intolerance to seawater, along with the fact that they formed early in geological history.

5. How many species of myriapods are there?

Nearly 13,000 species of arthropod are categorized in the Myriapoda the “many-legged ones”. All myriapods are terrestrial types.

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