carapace

References

Images

Diagram comparing the plastron and carapace in terrestrial and marine turtles, showing labeled illustrations of a turtle's ventral and dorsal shells and a skeletal view highlighting the relationship between the shells and axial skeleton.

Diagram illustrating the evolutionary stages of turtle shell development, showing skeletal outlines of Eunotosaurus, Pappochelys, Odontochelys, and Proganochelys with red highlighting the expanding shell area over time. Below, side-by-side illustrations compare the body structure and stride length of early reptiles with flexible spines and fast crawling to Eunotosaurus and later turtles with rigid spines and slower movement.

carapace

zoology

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 22, 2026

Quick Summary

Diagram comparing the plastron and carapace in terrestrial and marine turtles, showing labeled illustrations of a turtle's ventral and dorsal shells and a skeletal view highlighting the relationship between the shells and axial skeleton. — turtle skeleton The carapace and plastron each arose from two types of bones: dermal bones that form in the skin and endochondral bone (bone arising from cartilage) derived from the skeleton.

The term "carapace" refers to a hard, protective shell covering the back or part of the back of certain animals, such as turtles and crabs. This shell can be bony or chitinous.123

In zoology, the carapace is a significant feature in crustaceans. It develops as a fold from the rear of the head and can extend over the trunk, sometimes enclosing the entire body, limbs, and gills. In some crustaceans, like clam shrimps and ostracods, the carapace is divided into two parts, resembling a clam's shell. However, not all crustaceans possess a carapace; it is absent in groups like anostracans, amphipods, and isopods. In some species, like barnacles, the carapace forms a mantle that secretes shell plates. The structure and presence of the carapace can vary greatly among different crustacean groups.45

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

6 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

- percussion instrument
  The Americas
  Notched turtle carapaces are scraped in the Caribbean. The jawbone of a horse, mule, or donkey, with its teeth left in, is played throughout the Americas; its use among coastal Peruvians of African descent goes back to the 18th century. In the United States it has been…
  Read More
  Notched turtle carapaces are scraped in the Caribbean. The jawbone of a horse, mule, or donkey, with its teeth left in, is played throughout the Americas; its use among coastal Peruvians of African descent goes back to the 18th century. In the United States it has been…
  Read More
- stringed instrument
  The lyre
  …he brushed against a turtle carapace that lay on the ground and, as he did so, heard its sinews begin to vibrate. The tale is interesting for two reasons: first, the turtle shell was, in fact, frequently used as the resonator of the Greek lyra, and, second, the tale makes…
  Read More
  …he brushed against a turtle carapace that lay on the ground and, as he did so, heard its sinews begin to vibrate. The tale is interesting for two reasons: first, the turtle shell was, in fact, frequently used as the resonator of the Greek lyra, and, second, the tale makes…
  Read More