Mandible ( Latin Mandibulata ) - in some classifications one of the three subtypes of the arthropod type (Arthropoda sl, or Euarthropoda). It is characterized by a unique specialization of the limbs of the first 2-3 segments of the body (not counting the acron ) in the form of chewing appendages. The extremities of segment II are transformed into mandibles (mandibles, or upper jaws), limbs of segment III - into maxilla I ( maxillae from Crustacea, maxillae from Hexapoda), limbs of segment IV (except crustaceans of class Cephalocarida and part of millipedes ) - into maxilla II. In addition, the unique features of this taxon are: the presence of superlingivites (appendages lying between the mandibles and maxillae I), specially arranged ommatidia of the facet eyes , including the crystalline cone and the molar glands ( Y-shaped organ in crustaceans and prothoracic glands in insects ), secreting eczysone midworm . All representatives of this subtype retain antennas I (acronym appendages).
| Mandible |
Stag Beetle ( Lucanus cervus ) |
| Scientific classification |
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| No rank : | Bilateral symmetrical |
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| International scientific name |
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Mandibulata Snodrgass, 1935 |
| Overclasses |
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- Crustaceans
- Millipedes
- Insects
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This taxon is considered in the rank of subtype or infratype. The Russian-speaking name zhilnos-bearing for it was first used by O. A. Chernova (Subtype Mandibulata. Zhalon-bearing arthropods // Fundamentals of paleontology. Handbook for paleontologists and geologists of the USSR. T. 9. Arthropods - tracheal and chelicerae. 1962. M .: publishing house of the USSR Academy of Sciences. S. 17–374).
The mandible subtype includes three superclasses: crustaceans (Crustacea, or Eucrustacea), millipedes (Myriapoda), and insects (Hexapoda, or Insecta).
Prior to the isolation of the Mandibulata taxon by R. E. Snodgrass (1935), crustaceans, together with sea spiders (Pantopoda) and horseshoe crabs (Xiphosura), belonged to the subtype of gill-breathing (Branchiata), and insects and millipedes, together with arachnids (Arachnida), belonged to the subtype of tracheata (Tracheata) . The tracheal subtype in this sense is an artificial group, since the common adaptations for its terrestrial lifestyle ( tracheal respiratory system , malpighian vessels ) for its members arose independently in several taxa several times. Sometimes the name Tracheata is used for the Atelocerata group, which combines insects and millipedes . At the beginning of the 19th century, synapomorphies of horseshoe crabs and arachnids were found, later sea spiders were brought closer to them. These three groups are combined into a subtype of Pseudognatha .
