A carapace is a

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

(upper) section of the

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

or shell in a number of animal groups, including

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s, such as crustaceans and

arachnid Arachnids are arthropods in the Class (biology), class Arachnida () of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, camel spiders, Amblypygi, wh ...

s, as well as vertebrates, such as turtles and

tortoises Tortoises ( ) are reptiles of the family Testudinidae of the order Testudines (Latin for "tortoise"). Like other turtles, tortoises have a turtle shell, shell to protect from predation and other threats. The shell in tortoises is generally hard ...

. In turtles and tortoises, the underside is called the plastron. In botany, a carapace refers to the hard outer cover of a seed which protects the inner embryo.

Crustaceans

In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and

thorax The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

, as distinct from the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

behind). Where it projects forward beyond the eyes, this projection is called a rostrum. The carapace is calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera,

ostracod Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...

s, and isopods, but isopods only have a developed "cephalic shield" carapace covering the head.

Arachnids

s, the carapace is formed by the fusion of prosomal tergites into a single plate which carries the eyes, ocularium, ozopores (a pair of openings of the scent gland of

Opiliones The Opiliones (formerly Phalangida) are an Order (biology), order of arachnids, Common name, colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs (see below). , over 6,650 species of harvestmen have been discovered w ...

) and diverse phaneres. In a few orders, such as

Solifugae Solifugae is an Order (biology), order of Arachnid, arachnids known variously as solifuges, sun spiders, camel spiders, and wind scorpions. The order includes more than 1,000 described species in about 147 genus, genera. Despite the common names, ...

and

Schizomida Schizomida, also known as sprickets or short-tailed whip-scorpions, is an order of arachnids, generally less than in length. The order is not yet widely studied. E. O. Wilson has identified schizomids as among the "groups of organisms that des ...

, the carapace may be subdivided. In Opiliones, some authors prefer to use the term carapace interchangeably with the term cephalothorax, which is incorrect usage, because carapace refers only to the dorsal part of the exoskeleton of the cephalothorax. Alternative terms for the carapace of arachnids and their relatives, which avoids confusion with crustaceans, are prosomal dorsal shield and peltidium.

Turtles and tortoises

The carapace is the

(back) convex part of the shell structure of a

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

, consisting primarily of the animal's rib cage, dermal armor, and scutes.

References

External links

* {{Turtle terms Animal anatomy

Crustaceans

Arachnids

Turtles and tortoises

See also

References

External links