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Crustaceans have a pair of mandibles that typically consist of an enlarged basal segment (coxa) and a palp (sensory feeler) consisting of all other segments. In some groups, such as the Branchiopoda, the palp is reduced or absent. Crustacean mandibles may be equipped with special teeth (molar and incisor processes).
Crustaceans comprise a number of classes, with various feeding modes supported by a range of adaptations to the mouthparts. In general, however, crustaceans possess paired mandibles with opposing biting and grinding surfaces. The mandibles are followed by paired first and second maxillae.
The decapod (crustaceans, such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon . [1] [2] Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail:
They have adaptations to allow for this including stout flattened teeth, hypertrophied jaw adductor muscles and robust jaws to feed on hard prey such as crustaceans and molluscs. Sharks that crush prey have teeth with small, low rounded cusps that are numerous per row, or are molariform. The molariform teeth are smoothly rounded, lack cusps ...
The specific derived morphology of the teeth on the mandible varies depending on whether the insect eats broad-leafed herbs or grasses. [ citation needed ] This same simple structure is seen in all of the remaining Polyneopteran insect orders, with the exception of the Paraneoptera ( Hemiptera , Thysanoptera , and Phthiraptera ).
The maxilla is the main bone of the upper jaw. The premaxilla is a smaller bone forming the anterior of the animal's upper jaw. The dentary is the main bone that forms the lower jaw (mandible). The predentary is a smaller bone that forms the anterior end of the lower jaw in ornithischian dinosaurs; it is always edentulous and supported a horny ...
Many Biblical scholars believe that the classification of animals was created to explain pre-existing taboos. [18] Beginning with Saadia Gaon , several Jewish commentators started to explain these taboos rationalistically; Saadia himself expresses an argument similar to that of totemism , that the unclean animals were declared so because they ...
Triops longicaudatus is a member of the crustacean class Branchiopoda, which primarily contains freshwater animals with gills on their legs. The class Branchiopoda is divided into the subclasses Sarsostraca, containing fairy shrimp, and Phyllopoda, containing all other members (cladocerans, clam shrimps, and the tadpole shrimp).