Tag Archive: crabs

Kingdom: Animalia
Phylum: Arthropoda (invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages
Subphylum: Crustacea (crabslobsterscrayfishshrimpkrill and barnacles). Distinguished from other groups of arthropods, such as insectsmyriapods and chelicerates, by the possession of biramous (two-parted) limbs
Class: Malacostraca  (crabslobsterscrayfishshrimpkrillwoodlice, scuds (Amphipoda), mantis shrimp and less familiar animals)
Subclass: Eumalacostraca
Superorder: Eucarida  (decapodskrill and Amphionides)
Order: Decapoda (literally “ten-footed”)  Includes crayfishcrabslobstersprawns and shrimp.
Suborder: Pleocyemata;  members of the Reptantia (including crabs, lobsters, crayfish, and others)
Infraorder: Anomura
Superfamily: Paguroidea (hermit crabs)
Family: Lithodidae (stone crabs)

Genus/species: Cryptolithodes typicus

 GENERAL CHARACTERISTICS: The carapace covers the thoracic segments extending so far out covering the tips of the legs. The rostrum is widest at the base and narrower at the tip. Chelipeds are covered with rough tubercles. Carapace color is variable, from dark gray-blue to bright orange, white (especially in small individuals), or red (especially in males). The central part of the carapace is often a different color than the “wings”. Carapace width to 8 cm (3 inches).

Cryptolothodes sitchensis has a similar carapace but its rostrum is widest at the tip and its chelae are smooth.

 Butterfly Crab14453583299_3d6be76343_oDISTRIBUTION/HABITAT: Marine from Amchitka Island, Alaska to Santa Rosa Island, CA. Found in Rocky banks, shell rubble near rocky cliffs in open coast or inland waters, Depth Range: Low intertidal to 45 m (150 feet).

Butterfly Crab14453618558_e56e0e248d_o

DIET IN THE WILD: Feeds on bryozoans, coralline algae.


wallawalla.edu/academics/;  www.wallawalla.edu/academics/departments/biology/rosario/…

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 Photo vetted, Margarita Upton Biologist II Steinhart Aquarium California Academy of Sciences


KINGDOM      Animalia

PHYLUM        Arthropoda  (External skeleton, segmented body and jointed appendages)

SUBPHYLUM  Crustacea

CLASS          Malacostraca

ORDER         Decapoda  (ten legged)

FAMILY        Hippidae  (mole crabs or sand crabs)

GENUS/SPECIES  Emerita analoga



 Grey or sand colored exoskeleton without spines or claws.  The eyes are on long stalks and the antennae are also elongated so as to project above the surface of the sand. The legs and uropods have hairy margins to assist in digging and for use in collecting food and transferring it to the mouth.  The first pair of antennae reach above the sand for respiration, and the second pair, resembling feathers, are extended when the crab feeds. The female is nearly twice as large as the male up to 35 mm  (1.4 in) long and 25 mm (1.0 in) wide.

The sand crab always moves backwards when burrowing or crawling.


Pacific coast from Alaska to Baja California in the northern hemisphere and between Ecuador and Argentina in the southern hemisphere. E. analoga live in the swash zone (area of breaking waves) of the sandy beach intertidal zone.


Antennae collect small organisms, mostly dinoflagellates which are brought to the mouth and consumed.


During the reproductive season (February-October), females can produce one clutch per month of 50-45,000 eggs, which take approximately 30 days to develop. Once the eggs hatch, the larvae are planktonic for 4-5 months.


Fish, water birds, and shorebirds.

The barred surfperch is a very common fish in the surf zone, and sand crabs have been found to make up 90% of its diet.

Emerita analoga are  also used as bait by fishermen.



Sand crabs are known to carry parasites. They are an intermediate host of parasitic worms which are passed on to the predators of sand crabs. Sea otters and birds can eat many crabs per day, and the ingested parasites have been known to kill these predators.

Researchers monitor levels of DDT and domoic acid (a diatome neurotoxin) on a regular basis to assess the health of the ocean.


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Kingdom:  Animalia

Phylum:     Arthopoda

Class:          Malacostraca

Order:        Decapoda

Family:      Epialtidae

Genus/species;  Pugettia producta



 Mostly dark brown to green varying depending on the type of algae consumed. Like other members of its family, noted for its unique, elongated carapace with extended rostrum like an upside down shovel with the handle end towards its mouth. and four pairs of relatively long, slender walking legs. Because of these features, the family common name is “spider crabs.”

Most crabs in this family are called masking crabs; they attach fragments of shells and algae to their carapace for camouflage. P.producta, a large active crab, maintains a clean surface, perhaps for ease of movement.  It is a feisty animal; long legs are dextrous, and claws pinch hard.


 Alaska to Baja California in rocky intertidal in kelp beds and tidepools with abundant surfgrass or algae.  The crab uses the vegetation as protection from  sun and predators. Subtidal to 70 m (230 ft).


Mainly a nocturnal vegetarian feeding on bull kelp, sea lettuce, rockweed and other kelp. Occasionally will take barnacles, mussels, hydroids, and bryozoans in winter when vegetation is scarce.


Reproduction and Development: Females usually mate June to July, though can mate year round. Fertilized eggs develop for several months underneath the female’s abdomen.



Preyed upon by sculpins, gulls, cabezon, and sea otters among others.


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Phylum Arthropoda, Subphylum Crustacea, Class Malacostraca. Order Decapoda, Family Porcellanidae

Neopetrolisthes maculosus

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DISTRIBUTION: tropical seas confined to the western Pacific and Indo Australian. 

HABITAT: Often be found hiding in amongst its host anemone.  When disturbed they will hide under the anemone away from predators.  Pairs of the species can be often seen living in the same anemone and quite often they will try to defend their territory from anemonefish although the anemonefish generally prevails due to its large size.

APPEARANCE: Color may be varied. N. maculosus body cream white with ground red peas.  The body is round, claws large and flat, sharp.  Males will generally grow larger than the females and the crab is generally less than 5cm (2 in) in width, 2.5cm length (1 in).

DIET: They feed by combing plankton and other organic particles from the water using long setae (feathery hair or bristle-like structures) on the mouthparts. These animals will also scavenge on the sea floor for detritus.

REMARKS: They share the general body plan of a squat lobster, but their bodies are more compact and flattened, an adaptation for living and hiding under rocks. Porcelain crabs are quite fragile animals, and will often shed their limbs to escape predators, hence their name. The lost appendage can grow back over several moults. Porcelain crabs have large chelae (claws), which are used for territorial struggles, but not for catching food. The fifth pair of pereiopods are reduced and are used for cleaning.

Reef Partners Cluster PR33 Small Giant Clams Exhibit

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