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For example, in horseshoe crabs, they are like pincers, whereas in spiders, they are hollow and contain (or are connected to) venom glands and are used to inject venom to disable prey prior to feeding. In some spiders, the chelicerae have teeth, which are used to macerate prey items to assist digestion by secreted enzymes.
Both pseudoscorpions and harvestmen have additional structures on their chelicerae that are used for grooming (papillae in pseudoscorpions, cheliceral teeth in Opiliones). [1] In Paratrechalea , males and females have shown to have a chelicerae dimorphism, because the chelicerae is used as a mating signal for females.
H. sexdentatus have a distinctive square carapace (shell) with two teeth on either side. The chela (claws) are typically short, but can be large in males. [3] These crabs are primarily grey, but have two basic color and size types for patch markings: pale and dark.
Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to 4 m (13 ft). [6] Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation.
A typical radula comprises a number of bilaterally-symmetrical self-similar rows of teeth rooted in a radular membrane in the floor of their mouth cavity. Some species have teeth that bend with the membrane as it moves over the odontophore, whereas in other species, the teeth are firmly rooted in place, and the entire radular structure moves as one entity.
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 ...
Horseshoe crabs are often caught for their blood, which contains Limulus amebocyte lysate, a chemical used to detect bacterial endotoxins. Additionally, the animals are used as fishing bait in the United States and eaten as a delicacy in some parts of Asia. In recent years, horseshoe crabs have experienced a population decline.
Each side of the carapace consists of nine lateral teeth with the last extending outward. [6] Between the eye sockets there are six partially fused frontal teeth. [6] Arenaeus cribrarius has ten legs since it is a part of the order decapoda. [6] The first four pairs of legs have yellow tips and are used for walking. [6]