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Myriapoda

life science Maturity 5-7 Next article →

Myriapods are a diverse group of land-dwelling arthropods. This subphylum includes well-known creatures like centipedes and millipedes. There are approximately 13,000 different species currently living on Earth. All myriapods are terrestrial, meaning they live on land. They play a vital role in many ecosystems. Most species live in moist forests where they act as detritivores. This means they eat decaying plant material and help recycle nutrients.

Tachypodoiulus niger 1
Tachypodoiulus niger 1

The anatomy of a myriapod is specialized for life on land. Most possess a single pair of antennae on their heads. They also have simple eyes, though some groups are entirely eyeless. For example, the centipede order Geophilomorpha lacks eyes completely. In contrast, house centipedes, or Scutigera, have large compound eyes.

HouseCentipedeCloseup
HouseCentipedeCloseup

Their mouthparts are located on the underside of the head. This includes an epistome and labrum for the upper lip. Inside the mouth, they use mandibles to process food. To breathe, they use spiracles, which are tiny openings. These connect to a tracheal system that moves air through the body.

HouseCentipedeCloseup
HouseCentipedeCloseup

Myriapods grow through a fascinating process called anamorphosis. Most young myriapods hatch with only a few body segments. They also start with very few pairs of legs. As they grow, they undergo repeated moulting, which is shedding their skin. During this process, they add new segments and limbs. There are three specific types of anamorphosis. Euanamorphosis involves adding segments during every moult, even after reaching maturity. Emianamorphosis adds segments only until a certain stage is reached. Finally, teloanamorphosis stops adding segments once the adult form is achieved.

Scutigerella 42508806
Scutigerella 42508806

Scientists categorize living myriapods into four distinct classes. The first is Chilopoda, which contains the centipedes. These are fast, nocturnal predators that hunt larvae, worms, and even small rodents. Some species, like Scolopendra gigantea, can grow quite large. The second class is Diplopoda, which includes the millipedes. Most millipedes are slower and feed on leaf litter. While most have between 36 and 400 legs, the species Eumillipes persephone has 1,306 legs.

Tachypodoiulus niger 1
Tachypodoiulus niger 1

The third class is Pauropoda, which are tiny soil-dwellers. They are often only 0.5 to 2.0 mm long.

Eurypauropodid (12742282145) crop
Eurypauropodid (12742282145) crop

The fourth class is Symphyla, known as garden centipedes. These are small animals that live in the soil.

Scutigerella 42508806
Scutigerella 42508806

History shows that myriapods have been part of Earth's biology for eras. Molecular evidence suggests they diversified during the Cambrian Period. However, the oldest known fossil record dates to the Late Silurian or Early Devonian. A fossil called Pneumodesmus provides early evidence of air-breathing on land. Other ancient species include Kampecaris obanensis and Archidesmus sp. We also know of extinct giants called Arthropleuridea. The most famous genus, Arthropleura, could reach lengths of up to 2.5 meters.

ArthropleuraSide
ArthropleuraSide

Classification of myriapods remains a subject of intense scientific debate. Researchers use different hypotheses to explain their evolutionary relationships. The Mandibulata hypothesis suggests they are related to Pancrustacea. The Atelocerata hypothesis links them closely to Hexapoda, or insects. Another theory, the Paradoxopoda hypothesis, suggests a link to Chelicerata. Some molecular studies even suggest Euthycarcinoids are their closest extinct relatives. Scientists use morphological studies of body shapes and molecular studies of DNA to test these ideas.

Various myriapod phylogenies
Various myriapod phylogenies

Understanding myriapods helps us grasp the complexity of terrestrial life. Their ability to move from water to land was a major evolutionary step. They occupy various niches, from microscopic soil dwellers to large predators. Some species even demonstrate bioluminescence, the ability to produce light. While some centipedes can bite and some millipedes produce noxious secretions, they are essential to the environment. By breaking down organic matter, they maintain the health of forest floors. The study of these animals, called myriapodology, continues to reveal new secrets about life on Earth.

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🖼️ Images & Media (7)
File:HouseCentipedeCloseup.jpg
HouseCentipedeCloseup.jpg
File:Scolopendra fg01.JPG
Scolopendra fg01.JPG
File:Tachypodoiulus niger 1.jpg
Tachypodoiulus niger 1.jpg
File:Scutigerella 42508806.jpg
Scutigerella 42508806.jpg
File:Eurypauropodid (12742282145) crop.jpg
Eurypauropodid (12742282145) crop.jpg
File:ArthropleuraSide.jpg
ArthropleuraSide.jpg
File:Various myriapod phylogenies.png
Various myriapod phylogenies.png
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