Heikegani

Taxobox
name = Heikegani


image_width = 280px
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Malacostraca
ordo = Decapoda
subordo = Pleocyemata
infraordo = Brachyura
familia = Dorippidae
genus = "Heikea"
species = "H. japonica"
binomial = "Heikea japonica"
binomial_authority = (von Siebold, 1824)

Heikegani (平家蟹, ヘイケガニ) ("Heikea japonica") is a species of crab native to Japan, with a shell that bears a pattern resembling a human face. It is locally believed that these crabs are reincarnations of the spirits of the Heike warriors defeated at the Battle of Dan-no-ura as told in the Heike Monogatari ("The Tale of the Heike"). The pattern of ridges on the carapace serves a very functional purpose as sites of muscle attachment. Similar patterns are found on species in many parts of the world, including fossilized remains.

Heikegani were used by Carl Sagan in his popular science television show "" as an example of unintentional artificial selection. However, some experts have questioned this. The story goes that the crabs with shells resembling Samurai were thrown back, while those not resembling Samurai were eaten, giving the former a greater chance of reproducing. [http://crustacea.nhm.org/people/martin/publications/pdf/103.pdf] However, the maximum width of adult heikegani crabs is only about 30 mm (1.2 inches), so some fishermen throw these crabs back into the sea regardless of appearance. But smaller specimens may have been eaten in the past, before mass fishing. It is difficult to know for sure how much of the crab's shape and quantity has been dictated by artificial selection.

References

*cite journal |quotes=no | author=Martin, J. W. | title=The Samurai Crab | journal=Terra | year=1993 | volume=31 | issue=4 | pages=30–34 | url=http://crustacea.nhm.org/people/martin/publications/pdf/103.pdf (This site contains excellent colour photographs of these crabs, as well as arguments against the theory that they were formed through selection pressure exerted by human aesthetic impulses.)

External links

* [http://www.lib.pref.fukuoka.jp/tosho/kou/tck031.htm Illustrations] of Heikegani at the [http://www.lib.pref.fukuoka.jp Fukuoka Prefectural Library Web site] . The top illustration is of a Heikegani and the middle one is of a Samehadaheikegani (Paradorippe granulata).