Terrestrial crab

"Land crab" redirects here. For the car known as the "landcrab", see BMC ADO17.
Johngarthia lagostoma (Gecarcinidae), a terrestrial crab found on Ascension Island, where it is the largest native land animal

A number of lineages of crabs have evolved to live predominantly on land. Examples of terrestrial crabs are found in the families Gecarcinidae and Gecarcinucidae, as well as in selected genera from other families, such as Sesarma,[1] although the term "land crab" is often used to mean solely the family Gecarcinidae.[2]

Terrestriality and migration

There is no clear distinction between "terrestrial", "semi-terrestrial", and "aquatic" crabs.[2] Rather, there is a continuum of terrestriality displayed among the true crabs, although even the most land-adapted crabs must still return to water to release their eggs.[3] Some species of terrestrial crabs can be found many kilometres from the sea, but have to complete annual migrations to the sea.[3] For example, following the Indian Ocean monsoon, the Christmas Island red crab (Gecarcoidea natalis) migrates en masse, forming a "living carpet" of crabs. The crabs can travel up to 1.46 km (0.91 mi) in a day, and up to 4 km (2.5 mi) in total.[4]

Ecology

Terrestrial crabs have often evolved from freshwater crabs, since the physiological changes needed for living in fresh water are pre-adaptations for terrestrial living.[5] On some oceanic islands, terrestrial crabs occupy the top of the energy pyramid.[2]

See also

References

  1. ↑ Richard G. Hartnoll (1988). "Biology of the land crabs: an introduction". In Warren W. Burggren & Brian Robert McMahon. Evolution, systematics, and geographical distribution. Cambridge University Press. pp. 6–54. ISBN 978-0-521-30690-4.
  2. ↑ 2.0 2.1 2.2 Warren W. Burggren & Brian Robert McMahon (1988). "Biology of the land crabs: an introduction". In Warren W. Burggren & Brian Robert McMahon. Biology of the Land Crabs. Cambridge University Press. pp. 1–5. ISBN 978-0-521-30690-4.
  3. ↑ 3.0 3.1 Colin Little (1990). "Life on land". The Terrestrial Invasion: an Ecophysiological Approach to the Origins of Land Animals. Cambridge studies in ecology. Cambridge University Press. pp. 201–275. ISBN 978-0-521-33669-7.
  4. ↑ Ben Hoare (2009). "Red crab". Animal Migration: Remarkable Journeys in the Wild. University of California Press. pp. 74–75. ISBN 978-0-520-25823-5.
  5. ↑ Michael Dobson (2004). "Freshwater crabs in Africa" (PDF). Freshwater Forum 21: 3–26.

External links