Myriapoda

The myriapodes ( Myriapoda , of the Greek μύριος murios , ten thousand, and ποῦς pous, podos , foot)) a class of animals articulated, Arthropode S form, commonly called " mille-pattes". They include/understand the animals which, like the iule S or the scolopendre S, are composed of a head followed by many similar rings, carrying each one one or two pairs of legs.

The myriapodes are Mandibulates which can have large numbers of segments postcephalic carrying each one a pair of legs. At the diplopodes the segments are regoupés 2 to 2 formant of the rings carrying 2 pairs of legs.

From any point of view, the myriapodes must be regarded as most primitive of the arthropods.

Anatomy

The head comprises a pair of antennas, an upper lip or labre , a pair of mandibles, and two pairs of jaws.

The rings which follow the head carry each one either one, or two pairs of legs, without the total usually exceeding a hundred. The English expression centipède is preferable with the expression millepede to indicate these animals.

In the body of the myriapodes, all is lengthened and follows the periodicity of the rings: the digestive tract is rectilinear, the heart is formed many rooms in linear series, the nervous system is out of etc, climbing climbing rope

The breathing apparatus is composed of Trachée S analogues with those of the insects, and perfectly metamerized.

The only sensors are tactile hairs, and simple eyes or Ocelle S.

They undergo light metamorphoses of the exit of egg at the adulthood.

Ecology

The myriapodes all are of the terrestrial animals. The myriapodes are distributed on all the ground, in the tropical countries live the greatest forms.

All these species live hidden during the day, and leave during the night.

Classification of the animals

The myriapodes form a clade with the still discussed monophylie. The 4 classes which compose it (Diplopodes, Pauropodes, Chilopodes, Symphyles) could not be related. One classically divides them into two orders according to whether they have two pairs of legs by rings ( chilognathes or diplopode S) or only one ( chilopodes ). It is with the latter that are referred the poisonous species, whose mode is carnivorous.

The myriapodes were regarded a long time as close relations of the insects sharing with them the presence of uniramés Appendices and tubes of Malpighi. The analyzes of ARN ribosomial 18S do not confirm this proximity.

The Natural history museum of London, Chicago, Berlin, Vienna, and Saint-Pétersbourg are very implied in the knowledge of these species. They collected million specimens of various groups (Pauropoda, Symphyla, Chilopoda (5 orders) and Diplopoda (15-17 orders), representative of all the terrestrial types of ecosystems. Preserved in lalcool at 75° or in microscopic preparations on blades, they contribute to improve the classification as of these organizations (grouped today in 5000 species of myriapodes only to the national Muséum of natural history of Paris, joined together in 100.000 batch-samples comprising 1 million specimens at the beginning of the 20th century).

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