Mandibles of an ant
|Snodgrass , 1938|
The mandibular animals (Mandibulata) are a monophyletic group of the arthropods (Arthropoda), which is differentiated from the claw carriers (Chelicerata) on the basis of morphological features . The group is named after their mouthparts, the first pair of which are known as mandibles . The mandibular animals include the crustaceans (Crustacea) and the tracheal animals (Tracheata) with the millipedes (Myriapoda) and insects . Molecular biological studies, however, led to the assumption that the crustaceans and tracheas acquired the mandibles independently of each other. However, the tracheata hypothesis is now controversial, and more recently the hexipedes , to which the insects belong, are viewed as a subgroup of the crustacea, which are then also referred to as clade as pancrustacea .
The following characteristics connect the mandibular animals:
- The presence of a head armor (cephalon), which consists of the first six segments of the body armor (carapace) and on which in the original state two antennas and 3 pairs of mouthparts ( mandibles , 1st and 2nd maxilla) are formed as extremities .
Compound eyes , whose individual eyes (ommatidia) are made up of a crystal cone and eight retinula cells with a central rhabdom.
- As the original excretory organs , the nephridia are limited exclusively to the head area, where antenna and maxillary glands occur in the crustaceans. The tracheal animals have labial glands, which, however, only function as storage glands. The function of excretion is taken over by the Malpighian vessels in the digestive tract.
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- Rüdiger Wehner, Walter J. Gehring: Zoology . 24th edition Thieme Verlag KG, Stuttgart New York 2007, ISBN 978-3-13-367424-9
- Regier, JCJW Shultz, A. Zwick, A. Hussey, B. Ball, R. Wetzer, JW Martin and CW Cunningham; Arthropod relationships revealed by phylogenomic analysis of nuclear protein-coding sequences; Nature, 463, 2010, pp. 1079-1083. doi : 10.1038 / nature08742
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