Skip to main content
Select Source:

Isopoda

Isopoda (pill bugs, slaters, woodlice; class Malacostraca, superorder Pericarida) Large, diverse order of crustaceans, 5–15 mm long, forming a specialized subdivision of their superorder. Isopods occupy many habitats, from the deep sea to true terrestrial niches. Some are even parasitic. They are almost always dorsoventrally flattened and adapted for crawling, and lack a carapace. The pereon is made of up to seven somites, each bearing one pair of uniramous walking legs. The leathery, flexible exoskeleton may have brown or grey markings, and some species possess chromatophores which to some degree enable the animal to match its colour to the substratum. The head bears unstalked, compound eyes, and uniramous first antennae with sensory setae. Most isopods are scavengers and omnivores, with compact mouth-parts and a well-developed cardiac (or triturating) stomach. The pleopods, unlike those of most other Crustacea, have become developed for gaseous exchange. Burrowing is common in marine forms and some species can damage docks and wooden piling (e.g. Sphaeroma and the gribble, Limnoria). Characters such as internal fertilization, a marsupium (or brood pouch), and walking legs are pre-adaptations for the successful life-style of the terrestrial forms. There are 4000 known species, most of them marine.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Isopoda." A Dictionary of Zoology. . Encyclopedia.com. 6 Nov. 2018 <https://www.encyclopedia.com>.

"Isopoda." A Dictionary of Zoology. . Encyclopedia.com. (November 6, 2018). https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/isopoda

"Isopoda." A Dictionary of Zoology. . Retrieved November 06, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/isopoda

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

isopod

isopod (ī´səpŏd´), common name for crustaceans belonging to the order Isopoda and in the same subclass as lobsters and crayfish. Isopods are characterized by their flattened bodies, lack of a carapace, and gills located on the abdominal appendages. About 4,000 species are known. Most are aquatic; they are bottom-dwellers or are associated with water plants in freshwater or marine habitats. Some live under rocks on the shore, and some are terrestrial, living inconspicuously in surface litter or under logs. These, the pill bugs, or sow bugs, are the only large group of terrestrial crustaceans. Some isopods roll up like armadillos when disturbed. Some are parasitic, living on other crustaceans or in the mouths or on the gills of fishes. Most isopods are small, less than 1/2 in. (1.27 cm) long, but Bathynomus gigantea, a deep-sea species, may be over 1 ft (30 cm) long. Isopods are classified in the phylum Arthropoda, subphylum Crustacea, order Isopoda.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"isopod." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 6 Nov. 2018 <https://www.encyclopedia.com>.

"isopod." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (November 6, 2018). https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/isopod

"isopod." The Columbia Encyclopedia, 6th ed.. . Retrieved November 06, 2018 from Encyclopedia.com: https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/isopod

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

pill bugs

pill bugs See ARMADILLIDAE; ISOPODA.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"pill bugs." A Dictionary of Zoology. . Encyclopedia.com. 6 Nov. 2018 <https://www.encyclopedia.com>.

"pill bugs." A Dictionary of Zoology. . Encyclopedia.com. (November 6, 2018). https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/pill-bugs

"pill bugs." A Dictionary of Zoology. . Retrieved November 06, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/pill-bugs

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

isopod

isopodbod, clod, cod, god, hod, mod, nod, od, odd, plod, pod, prod, quad, quod, rod, scrod, shod, sod, squad, tod, Todd, trod, wad •demigod • amphipod • unipod •tripod • isopod • myriapod • decapod •cephalopod • monopod • macropod •gastropod • arthropod • sauropod •ramrod • Nimrod • hotrod • pushrod •goldenrod • Novgorod • slipshod •roughshod • eisteddfod • tightwad

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"isopod." Oxford Dictionary of Rhymes. . Encyclopedia.com. 6 Nov. 2018 <https://www.encyclopedia.com>.

"isopod." Oxford Dictionary of Rhymes. . Encyclopedia.com. (November 6, 2018). https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/isopod

"isopod." Oxford Dictionary of Rhymes. . Retrieved November 06, 2018 from Encyclopedia.com: https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/isopod

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.