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Carapace: A hardened plate (sclerite) covering the upper (dorsal) portion of the cephalothorax; [3] see also Carapace; Carpoblem: The principal tibial apophysis on the male pedipalp; also just called the tibial apophysis; Cephalic region or caput: The front part of the cephalothorax, separated from the thoracic region by the cervical groove [4]
The cephalothorax, also called prosoma, is composed of two primary surfaces: a dorsal carapace and a ventral sternum.Most external appendages on the spider are attached to the cephalothorax, including the eyes, chelicerae and other mouthparts, pedipalps and legs.
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:
The molted carapace of a lady crab from Long Beach, New York. In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum.
In spiders, the cephalothorax and abdomen are joined by a small, cylindrical pedicel, which enables the abdomen to move independently when producing silk. The upper surface of the cephalothorax is covered by a single, convex carapace, while the underside is covered by two rather flat plates. The abdomen is soft and egg-shaped.
In chelicerates and crustaceans, the cephalothorax is derived from the fusion of the cephalon and the thorax, and is usually covered by a single unsegmented carapace.In relation with the arthropod head problem, phylogeny studies show that members of the Malacostraca class of crustaceans have five segments in the cephalon, when not fused with the thorax to form a cephalothorax.
The spider's body is divided into two main parts: a rectangular, slightly rounded cephalothorax and larger ovoid abdomen that is narrower to the rear. [14] The male has a carapace, the hard upper part of the cephalothorax, [15] that is between 1.9 and 2.3 mm (0.07 and 0.09 in) long and 1.5 and 1.8 mm (0.06 and 0.07 in) wide. It is generally ...
Tagmata and major appendages of a spider: cephalothorax or prosoma and abdomen or opisthosoma The number of tagma and their names vary among taxa . For example, the extinct trilobites had three tagmata: the cephalon (meaning head), the thorax (literally meaning chest, but in this application referring to the mid-portion of the body), and the ...