Freikiefler
As ectognatha or Ectognatha a is morphological group of Sechsfüßer referred extending from the Sackkieflern (= Entognatha) due to the location of their mouthparts and by building their sensor differs.
features
The mouthparts of the free jaws - in contrast to the sack jaws - are not hidden in the head capsule. Rather, they are visible from the outside, and the mandibles and maxillae work freely on the underside of the head; in the case of the sack jaws, however, the mouthparts are hidden in a "mouth pocket". A well-known example of Freikiefler are the ants , whose mouthparts are clearly visible at all times. Inside the head there is a tentorium with front and rear arms.
The antennas of the Freikiefler are designed as whip antennas , while the Sackkiefler have link antennas . With them, accordingly, only the first antennae, the scapus , is equipped with muscles, while the second antennae, the pedicellus , contains a Johnstonian organ , and all the other members form a long flagellum.
The legs are also designed differently than those of the sack pines . In the free jaws, the tarsus is articulated and the praetarsus has paired claws that are connected to the last tarsal link via a joint. An empodium of the unpaired claw can be present as a rudiment, and an unpaired arolium can develop on the front of the praetarsus . The extremities of the 8th and 9th abdominal segment form the ovipositor in females as gonopods . At the end of the abdomen, some groups have an unpaired terminal filum in addition to the cerci .
On the sides of the thoracic segments of the original Freikiefler there are lateral lobes called paranota . From these the wings are formed in the derived forms, the flying insects .
Systematics
The two numerically small (and wingless) orders of the rock jumpers (Archaeognatha, approx. 450 species) and the small fish (Zygentoma, approx. 330 species) as well as the flying insects (Pterygota) with several hundred thousand species are counted among the free-jaws. So they correspond in their species composition to the insects .
The systematics of the six-pod is still very much under discussion. In the classic variant, the insects are compared to the remaining groups, which are collectively referred to as Sackkiefler (Entognatha) because of their mouth pocket (Hypothesis 1; Hennig 1953, 1969 (mod.)). Another hypothesis only summarizes the springtails and leg trawlers as a taxon called Ellipura and then assigns the double tails as the first branch to the insects (Hypothesis 2; Kukalova-Peck 1987, 1991).
Hypothesis 1 : The leg tracers, double tails and springtails form the sister group of insects:
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Hypothesis 2 : The leg tractors and springtails form the sister group of insects and double tails:
| Six-footed (Hexapoda) |
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supporting documents
- ↑ a b c d Bernhard Klausnitzer: Entognatha (Entotropha), Sackkiefler. In Westheide, Rieger (Hrsg.): Special zoology part 1: single-cell and invertebrate animals. Gustav Fischer Verlag, Stuttgart, Jena 1997; Pages 625-626.
literature
- Bernhard Klausnitzer: Entognatha (Entotropha), Sackkiefler. In Westheide, Rieger (Hrsg.): Special zoology part 1: single-cell and invertebrate animals. Gustav Fischer Verlag, Stuttgart, Jena 1997; Pages 625 ff.