Cryptolithodes sitchensis | |
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Species: | C. sitchensis |
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Cryptolithodes sitchensis | |
Cryptolithodes sitchensis, known as the umbrella crab, [2] is a species of lithodid crustacean native to coastal regions of the northeastern Pacific Ocean, ranging from Sitka, Alaska to Point Loma, California. [3] Its carapace extends over its legs such that when it pulls in its legs, it resembles a small stone. It lives in rocky areas from the low intertidal to depths of 17 m (56 ft). [3]
Cryptolithodes sitchensis has a half-moon shaped carapace extending over all of its eight walking legs and two chelipeds, giving them their common names of turtle crab, umbrella crab or helmet crab. The carapace can be 5–10 cm (2.0–3.9 in) at the adult stage and has scalloped edges. This carapace ranges from neutral sandy colors to bright oranges, reds, and purples. [4] : 192, 255 The rostrum extends forwards from the carapace, gradually widening before ending abruptly. From above, only the eyes and second antennae are visible. The ventral side is commonly white in color, and the abdomen is protected by multiple hard plates that lack raised margins. [4] : 407 The chelipeds are smooth. The fifth pair of walking legs are located at the posterior and are difficult to distinguish. [5]
C. sitchensis can be found from southern Alaska to southern California, where they are common. [5] [6] They live within 18 m (59 ft) of the intertidal zone along the exposed coasts of the Pacific Ocean. [5] Intertidal species of Lithodidae prefer habitats of cooler temperatures ranging from 0–25 °C (32–77 °F) and temperatures of 16 °C (61 °F) during larval development. This causes a restriction on their distribution as water temperatures change due to global warming. [7]
The distinguishing characteristic between C. sitchensis and C. typicus is that the rostrum of C. sitchensis is wider distally than proximally, while the opposite is found in C. typicus. Also, C. typicus has raised margins of the abdominal segments, while C. sitchensis does not. [4] : 407
The larvae of C. sitchensis have six tergites at the megalopal stage. Upon reaching the adult stage, the first and second abdominal segments have fused and the sixth tergite and telson are whole. C. sitchensis males and females have symmetrical abdomens, yet females have a greater number of accessory plates on the left side of the third tergite. [8]
C. sitchensis may be hard to spot due to its rough, rock-like exterior, but it is easily caught due to its slow movements. Found most commonly in the intertidal zone, this species feeds on coralline algae. The reason for the diverse colorations of its carapace may be camouflage with its surroundings. [9]
Natural predators of C. sitchensis include larger marine invertebrates, such as octopuses, seabirds, and marine mammals, such as otters.
A major threat to C. sitchensis in Southern California is deforestation and its effects on the giant kelp forests around the Channel Islands National Park. The forests of Macrocystis pyrifera form a protective canopy, fostering the ideal temperature for various species that are temperature-sensitive, such as C. sitchensis, and the growth of macroalgae and coralline algae needed for their survival. [10]
The Japanese spider crab is a species of marine crab that lives in the waters around Japan. It has the largest known leg-span of any arthropod.The Japanese name for this species is taka-ashi-gani,, literally translating to “tall legs crab”. It goes through three main larval stages along with a prezoeal stage to grow to its great size.
King crabs are a taxon of decapod crustaceans that are chiefly found in cold seas. Because of their large size and the taste of their meat, many species are widely caught and sold as food with the most common being the red king crab.
Petrolisthes elongatus, known as the New Zealand half crab, elongated porcelain crab, blue half crab, blue false crab or simply as the half crab or false crab, is a species of porcelain crab native to New Zealand.
The Puget Sound king crab, is a species of king crab which inhabits the oceans of the Pacific coast of North America from Alaska to central California. Adults are orange, red and purple in color, while juveniles are either mostly orange or have small blotches of red and purple. They can be recognized by their blunt bumps on their carapace. Puget Sound king crabs are larger than the similar brown box crab, with an average size of 6–10 inches (15–25 cm).
Oedignathus inermis is a species of king crab found off the Pacific coasts of the United States and Canada, from California to Alaska, and disjunctly around the coasts of Japan. It is the only species in the genus Oedignathus, and is sometimes called the granular claw crab, paxillose crab or tuberculate nestling lithode crab.
Cancer productus, one of several species known as red rock crabs, is a crab of the genus Cancer found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest.
Glebocarcinus oregonensis, commonly known as the pygmy rock crab, is a species of crab found on the Pacific coast of North America.
Pagurus hirsutiusculus is a species of hermit crab, commonly called the hairy hermit crab. It lives from the Bering Strait south to California and Japan, from the intertidal zone to a depth of 110 m (360 ft).
The purple shore crab is a common crab of the family Varunidae that is indigenous to the west coast of United States, Canada, and Mexico. H. nudus was first described in 1847 by Adam White, and in 1851, James Dwight Dana formally classified the species. H. nudus is a small, amphibious crab that is similar physically and behaviorally to Pachygrapsus crassipes and Hemigrapsus oregonensis. The purple shore crab is generally a dark purple color with olive green, red, and white spots. Mating season for H. nudus begins in mid-winter and larval crabs undergo 5 zoeal stages and a juvenile stage. Adult crabs mainly feed on algae but will occasionally scavenge other animals. H. nudus prefers inter-tidal and sub-tidal zones, and it can oftentimes be found sheltering under rocks or other debris. H. nudus demonstrates complex compensatory mechanisms to counteract fluctuating salinity and water oxygen concentrations, permitting it to live in a variety of different environments.
Hemigrapsus oregonensis is a small shore crab of the family Varunidae; formerly classified under the family Grapsidae. It is known under several common names, including yellow shore crab, hairy shore crab, green shore crab, mud-flat crab, bay shore crab and Oregon shore crab. Despite its common name, the crab actually has a wide variety of coloration. It is found along the West Coast of the United States and Canada, specifically along shorelines and similar geographical areas. In 2009, H. oregonensis was included on a list of animals petitioning for the endangered species label, but there was not enough scientific information available for it to be considered as such, so it remains unevaluated to the present day.
Dendraster excentricus, also known as the eccentric sand dollar, sea-cake, biscuit-urchin, western sand dollar, or Pacific sand dollar, is a species of sand dollar in the family Dendrasteridae. It is a flattened, burrowing sea urchin found in the north-eastern Pacific Ocean from Alaska to Baja California.
Pugettia producta, known as the northern kelp crab or shield-backed kelp crab, is a species of crab in the family Epialtidae.
Pagurus samuelis, the blueband hermit crab, is a species of hermit crab from the west coast of North America, and the most common hermit crab in California. It is a small species, with distinctive blue bands on its legs. It prefers to live in the shell of the black turban snail, and is a nocturnal scavenger of algae and carrion.
Petrolisthes eriomerus is a species of marine porcelain crab found in the eastern Pacific Ocean. It is commonly known as the flattop crab. It is a flattened, rounded animal, with a carapace up to 20 mm (0.8 in) across. It is a filter feeder, and also sweeps food from rocks.
Cryptolithodes typicus, often referred to as the butterfly crab or the turtle crab, is a species of lithodid crustacean native to coastal regions of the northeastern Pacific Ocean, ranging from Amchitka Island, Alaska to Santa Rosa Island, California.
Oregonia gracilis, commonly known as the graceful decorator crab, is a species of crab belonging to the family Oregoniidae. Like other decorator crabs it habitually attaches other organisms to its back. The sessile organisms are attached to hooked setae that act as a sort of velcro attachment. This decoration provides visual and chemical camouflage thus reducing predation risk. Pacific halibut are a major predator of O. gracilis. Other predators include octopus and sea otters. The main food source of O. gracilis is floating kelp and algae that they capture utilizing a waiting strategy in order to maintain cryptosis.
Pugettia gracilis, commonly known as the graceful kelp crab, is a species of small crab in the family Epialtidae. It lives among forests of kelp on the Pacific coast of North America.
Loxorhynchus grandis, commonly known as the sheep crab or spider crab, is a species of crab in the family Epialtidae. It is the largest crab found on the California coast. The species was first described to science by William Stimpson in 1857. The type specimen was collected on the coast of California, near San Francisco. Fossils from the late Miocene epoch indicate that this species is at least 11.63 to 5.333 million years old.
Eurynolambrus australis, commonly known as the triangle crab, and by its Māori name riangi, is a small species of crab that is widespread throughout New Zealand.
Cryptolithodes expansus is a species of king crab native to the Korean coast and Japan. They live in the sublittoral zone to a depth of approximately 50–60 metres (160–200 ft). Adults measure approximately 50 mm (2.0 in) wide and 80 mm (3.1 in) long and have a rostrum of about 10 mm (0.39 in).