|Lubbock , 1868|
The little pods (Pauropoda) are a class of the arthropods (Arthropoda) and are classified with the millipedes (Myriapoda). Around 540 species of these very small animals with a maximum length of 2 mm are known worldwide.
Way of life of the puntipods
Pauropods are widespread worldwide, with an average of five to ten individuals living in one liter of soil. They prefer to colonize the upper centimeters of loose, humus soil, but occasionally penetrate to a depth of 50 cm. The food spectrum of the pauropods is not yet fully known. So far investigated species feed on fungal threads ( hyphae ). To do this, they bite the ends of these threads with their mandibles and suck out the contents with the help of strong suction muscles on the foregut.
Lesser pigeon hole
Like all members of the Myriapods, the puntipods are characterized above all by a uniform structure of the body segments. The native little pennies have nine or ten segments, each carrying a pair of legs. However, if you look at them from above, you can see fewer than ten back plates, as some segments do not form any of these structures, known as tergites. The tergites of the 2nd to 6th back plates each have a clearly visible sensory organ in the form of a long bristle ( trichobothrium ).
The legs are built uniformly, only the first pair of legs can have fewer limbs or be completely absent. On the legs 2–12 the animals have fold-out sacs ( coxal organs ), on the legs 3–12 additional pen-like structures ( styli ).
The head of the animals is very small, so that the brain protrudes into the first trunk segment. The pinnipedes do not have eyes, but the head is equipped with tactile and chemoreceptors on both sides (pseudoculus). The antennas are made up of a chain of similar antenna links and form a so-called link antenna. This has several minor flagella at its end.
The mandibles of the animals are pointed and consist of only one member. They are used to pierce the mushroom threads. The 1st maxillae are narrow and lie next to a triangular plate that is formed from the associated breast plate ( sternite ). The second maxilla is absent, as in the dwarf pods .
Reproduction and development
The males lay droplets of sperm on a web, which consists of a network with several "support rods". The females ingest the sperm drop from this construction.
The development is only known from the species Pauropus silvaticus . Here, after embryonic development, a nymph hatches with only three pairs of legs, further pairs of legs are created after the moults. As adults, these animals no longer molt.
Systematics of the few feet
The pinnipedes form the dignatha together with the bipedes due to the merging of the basal limbs of the 1st maxilla into a lower lip (gnathochilarium), the loss of the 2nd maxilla or the rudimentary attachment of the same in the embryonic development, the genital openings in the second segment, close to the tracheal openings the legs as well as a young animal with only three pairs of legs.
Together with the dwarf pods , the Dignatha form the Progoneata taxon due to the formation of the intestines and fatty bodies within the yolk and the structure of the mechanoreceptors (trichobothria). This group is usually compared to the centipedes as a sister group.
Internally, the pinnipedes become the original Hexamerocerata (with 12 back plates and tracheal opening on the first pair of legs), which only live in the tropics, as well as the Tetramerocerata (reduced number of back plates, no tracheal system) with some native species. The native species are classified into four families:
- Dunger, W. (1993). Pauropoda. In: Gruner, HE (Ed.) Textbook of Special Zoology I.4, Arthropoda (without Insecta). Gustav Fischer, Jena a. a., pp. 1105-1111.
- Wolfgang Dohle : Progoneata , in: W. Westheide, R. Rieger (Ed.): “ Special Zoology Part 1: Protozoa and Invertebrates ”; Gustav Fischer Verlag, Stuttgart, Jena 1996; Pp. 592-600.