We explain what myriapods are, how they are classified and the habitat in which they live. Also, what are their characteristics, examples and more.
What are myriapods?
Myriapods or myriopods are known as a set of invertebrate animalsfrom the phylum of arthropods, popularly known as centipedes or millipedes. This is because they have an elongated and segmented body, with abundant pairs of legs, which in many aspects is similar to that of some insects.
Myriapods are not a very well-known group, perhaps because they are not easy to find. They are fast, creeping and elusive animals.which can at most be found in occasional humidity conditions, or in dark corners. However, up to 16,000 different species of myriapods are recognized, some poisonous and most harmless.
See also: Scorpio
Origin of the myriapods
The myriapods They are evolutionarily linked to the rest of their phylumespecially with hexapod insects, although there is no scientific consensus on this matter.
Its biological origin dates back to the Upper Carboniferous periodabout 310 million years ago.
In some cases There are records from the Silurian periodmore than 400 million years ago, meaning they are among the first land animals.
It is estimated that They have changed little since their origins, except in size.There is fossil evidence of myriapods up to one metre in length, as oxygen-rich atmospheric conditions allowed the emergence of animals (especially insects and arthropods) of enormous size compared to those we know today.
Lower classification of myriapods
Myriapods can be classified into four well-defined groups:
- Chilopods or centipedes. Also called centipedes, they include about 3,000 different species, all with a pair of legs per segment on their body, which can measure up to 30 cm. Some have poison in their mouthparts, as their diet is carnivorous.
- Diplopods or millipedes. Unlike centipedes, they have two pairs of legs per body segment, which gives them between 34 and 400 legs. Their diet is detritus-eating, making them fairly harmless to humans. Their long, cylindrical bodies vary among the 12,000 described species.
- Pauropoda. With few legs (9 to 11 pairs) and tiny bodies measuring between 0.5 and 2 millimetres, around 600 species of these detritus-eating myriapods are known.
- Symphyllums. Another type of small myriapod (0.5 to 8 millimetres) that lives in humid places and has soft bodies with 12 pairs of legs. There are between 160 and 200 different species known, with a saprophytic or herbivorous diet.
Habitat of myriapods
The myriapods They generally prefer habitats rich in moisturesince their bodies lose water at a rapid and constant rate. However, it is possible to find species adapted to desert climates and arid surfaces. Most of them are nocturnal animals, which avoid light and take refuge during the day under stones, logs or leaf litter.
Feeding of myriapods
Most myriapods are peaceful animals that eat plants or decaying matter, and even fungi, plant fluids and other organic waste. The exception are the chilopods, which are aggressive predators with a poisonous bite.
Respiration of myriapods
The respiration of these animals is similar to that of hexapod insects. It consists of a system of tracheae and spiracles along the bodywhich is traversed by the hemolymph thanks to a dorsal tubular heart. This design makes them vulnerable to desiccation, since they lack the waxy layer typical of insects.
Reproduction of myriapods
Reproduction of myriapods It is of sexual type, with direct or indirect inseminationIn the latter, the male leaves the spermatophores near the female, so that she can collect and store them, thus fertilizing her eggs inside her body.
In other species copulation occurs directlywith the individuals facing each other joining their lower parts, where the gonopods (sexual organs) are.
They are oviparous and The laying is usually numerous (up to 300 eggs) The female uses the stored sperm and then usually guards it until the young are born, after several weeks.
The babies They are born with few pairs of legs and few body segments.; as they live they add new segments. In some species, newborn offspring feed on their mother at birth.
Anatomy of myriapods
The body of myriapods is composed of two distinct parts:
- Head. Where the antennae, eyes and mouth are found, as well as the jaws and, in the case of chilopods, a first pair of modified legs that serve to hold the prey and inoculate the poison.
- Trunk. Elongated and segmented, from which the pairs of legs emerge and in which the tracheas for breathing and the reproductive and excretory organs are located. The number of pairs of legs varies greatly: the species with the most legs recorded is the diplopod. Illacme plenipeswith 375 pairs.
Millipedes in culture
Myriapods are animals about which humans still ignore many things. Their skittish nature and quick movements often intimidate or generate distrust, especially in larger species.
On the other hand, Contact between them and humans is quite sporadic.and their representation in culture is not very abundant. They are considered mysterious, linked to decomposition and death.
Venom of millipedes
The bite of the myriapods is only found in the case of the chilopods, and is usually painful, but not lethal. Their venom is incapable of killing a humanbut it does produce redness and swelling that usually disappears within 48 hours. People who are sensitive to the venom may experience anaphylactic shock, requiring immediate medical attention.
Some species of millipedes secrete irritating substances that They can cause discomfort to the touchespecially if they come into contact with mucous membranes or eyes. In this case, the area should be irrigated (washed with plenty of water) immediately.
Examples of myriapods
Some examples of myriapods are:
- Scolopendra cingulata. Commonly called the centipede, it is the largest myriapod in Europe (reaching 17 cm in length) and an active hunter of cockroaches, spiders and insects.
- Illacme plenipes. Millipede of American origin, in the state of California, considered the animal with the most legs in the world. It was discovered in 1926 and rediscovered in 2005.
- Psammodesmus brophorus. A millipede discovered in 2011 that houses up to ten species of moss on its back, which provide camouflage and protect it from fungi.