''Cryptolithodes typicus'', often referred to as the butterfly crab or the turtle crab, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of lithodid

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

native to coastal regions of the northeastern Pacific Ocean, ranging from Amchitka Island, Alaska to Santa Rosa Island, California.

Description

The crab's

butterfly Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

-shaped

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

has a stone-like camouflage, which it uses to blend in against the rocks of the

subtidal The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminate ...

and low intertidal zones. Carapace color within the species varies greatly, but small individuals (< in length) are typically white, while larger ones tend to have an assortment of vibrant colors. The carapace is exceptionally broad and completely hides the appendages when viewed from above or from the side; it has a median raised crest which is often a different color that contrasts with other parts. The male carapace is at its widest at a point further back than that of the female. The

cheliped A chela ()also called a claw, nipper, or pinceris a pincer-shaped organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through Neo-Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds ...

s of the male are relatively larger than the widest point of the female. The right claw is larger than the left and both claws are sharp, curved, and stout. Each segment of the walking legs has a dorsal crest.

Distribution

The butterfly crab resides on rocks within the subtidal and low intertidal zones. When its intertidal habitat is exposed to the atmosphere during extreme low

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

, it can be found clinging to the substratum in rock crevices or at the base of the seagrass ''

Phyllospadix ''Phyllospadix'', commonly known as surfgrass, is a genus of seagrass, a flowering plant in the family Zosteraceae, described as a genus in 1840. ''Phyllospadix'' grows in marine waters along the coasts of the temperate North Pacific. It is o ...

''. It has been found to a depth of .

Etymology

The genus name "''Cryptolithodes''" means "hidden stone", while its species name "''typicus''" denotes it as the genus'

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. The nickname "butterfly crab" is derived from the crab's carapace, which resembles a butterfly, and the nickname "turtle crab" derives from the way its carapace covers its appendages from above and the sides.

References

External links

* * * {{Portal bar, Crustaceans, Marine life King crabs Crustaceans of the eastern Pacific Ocean Anomura of the Pacific Ocean Crustaceans described in 1849 Taxa named by Johann Friedrich von Brandt Crustaceans of Canada Crustaceans of the United States Fauna of California Fauna of the Northwestern United States Fauna of British Columbia Fauna of Yukon Fauna of the Aleutian Islands

Description

Distribution

Etymology

See also

References

Further reading

External links