Invertebrate Skeletons


A skeleton is any mechanical system that interacts with muscle activity to allow movement and locomotion; the skeleton provides an external force or framework to restore muscles to their relaxed state. Invertebrate skeletons may be hydrostatic or stiff, either type serving to support the body and keep it in shape; stiff skeletons usually also have protective functions.

Keywords: hydrostatic skeleton; stiff skeleton; locomotion; support; joints

Figure 1.

Basic skeletal designs and the diversity of animal morphology that results. (a) Hydrostatic skeleton → ′worm′. (b) Incomplete exoskeleton → mollusc. (c) Complete exoskeleton → ′arthropod′. (d) Endoskeleton → echinoderm.

Figure 2.

The role of a helically wound fibre lattice in maintaining/restoring shape in a hydrostatic skeleton.


Further Reading

Alexander RMcN (1992) Exploring Biomechanics: Animals in Motion. New York: Scientific American Library.

Currey J (1970) Animal Skeletons. London: Edward Arnold.

Gordon JE (1978) Structures: or Why Things Don’t Fall Down. Harmondsworth, UK: Penguin.

Quillin KJ (2000) Ontogenetic scaling of burrowing forces in the earthworm Lumbricus terrestris. Journal of Experimental Biology 203: 2757–2770.

Thomas RDK and Reif WE (1993) The skeleton space – a finite set of organic designs. Evolution 47: 341–360.

Trueman ER (1975) The Locomotion of Soft‐Bodied Animals. London: Edward Arnold.

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How to Cite close
Willmer, Pat(Feb 2003) Invertebrate Skeletons. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0003640]