Symphyla

Zwergfüßer ( Symphyla )

The Zwergfüßer ( Symphyla ) are a class of arthropods ( Arthropoda ) and be filed with the millipedes ( Myriapoda ). Worldwide there are about 150 known species of this very small, pigment and eyeless animals. They are up to 9 mm long.

Lifestyle of Zwergfüßer

The Zwergfüßer live mainly in the upper soil layer ( duff ), under manure piles and under stones. They feed on rotting and also of living parts of plants. In mass occurrence they can act as pests, especially in nurseries ( in greenhouses ).

Construction of Zwergfüßer

Like all members of the Myriapoda drawing the Zwergfüßer mainly by a uniform structure of the body segments. The Zwergfüßer always have 12 segments, each bearing a pair of legs running. Looking at them from above, more than 12 back plates but you can often recognize ( at Scutigerella 15, otherwise to 25 ), because some segments form two of those named as tergites structures. The legs are built uniformly, only the first pair of legs may have fewer members or completely missing. On the legs 2-12 animals eversible sacs have ( Coxalorgane ), legs 3-12 additional stylus -like structures ( styli ).

The head of the animal is flat and has at the bottom of several flat-lying mouthparts ( mandibles and two pairs of maxillae ). The second pair of maxillae forming a lower lip. The antennas are made up of a chain of identical antenna elements and form a so-called antenna elements. Unlike all other Tracheentiere the Zwergfüßer have only a single pair Tracheenöffnungen ( stigmata ) near the Mandibelbasis, pull from where branched tracheae to the 4th body segment.

The rear end bears a pair of spinning stylus associated with spinning glands in the body, and a pair of mechanoreceptors ( trichobothria ).

Reproduction and Development

For copulation the males of the Zwergfüßer forms (seen in Scutigerella ) a long stalk secretion on which it issues a drop of sperm. This drop is taken from the females and stored in Mundvorraum. It resets individually on leaves of mosses from the eggs and fertilizes them there with the help of the sperm reservoir.

The juveniles of Zwergfüßer slip with a significantly reduced leg number ( Scutigerella with seven pairs of legs ) and get with each shedding a new pair of legs added until all segments are present. Even the animals skin on.

Nomenclature of Zwergfüßer

The Zwergfüßer form due to the colon and body fat formation within the yolk as well as the structure of the mechanoreceptors ( trichobothria ) together with the Dignatha ( millipedes and Wenigfüßer ) the taxon Progoneata. This group, the centipedes are compared as a sister group commonly.

The European species of the Zwergfüßer be divided into two families, the Scolopendrellidae ( for example, with Symphylella vulgaris ) and the Scutigerellidae ( with Scutigerella immaculate, p Tuscia, p pagesi, p remyi and S. sylvatica ). From both families fossils are now known. A representative of the genus Scolopendrella from the Baltic amber is the only fossil Scolopendrelliden; within the Scutigerelliden are two known species from the Baltic amber and one from the Dominican amber.