Crabs, Crayfishes, Lobsters, Prawns, and Shrimp

Order Decapoda

The Crabs, Crayfishes, Lobsters, Prawns, and Shrimp (Order Decapoda) includes 103 species across 32 families and 61 genera in our directory.

About Crabs, Crayfishes, Lobsters, Prawns, and Shrimp

Decapoda includes ~15,000 described species of crabs, lobsters, shrimp, and crayfish. Although primarily marine and freshwater, some species like hermit crabs and coconut crabs are fully terrestrial.

Economic Impact

The global shrimp industry alone is worth over $45 billion annually. Crayfish are important aquaculture species and invasive crayfish cause ecological damage estimated in the hundreds of millions annually in Europe and North America.

Ecological Role

Crayfish are keystone species in freshwater ecosystems, influencing water clarity, sediment dynamics, and plant communities. Hermit crabs play vital roles in nutrient cycling on tropical islands.

Families in Decapoda (32)

Species in Decapoda (103)

Atlantic Blue Crab

Callinectes sapidus

Portunidae

Identification: Blue Crabs of the South Atlantic Bight

Atlantic Ghost Crab

Ocypode quadrata

Ocypodidae

Identification: The only species of ghost crab along Atlantic beaches. Individuals are occasionally found north of Rhode Island, though they cannot survive the winters there. Update: articles in 2013 indicate that a breeding population is present on

Calico Crayfish

Faxonius immunis

Cambaridae

Identification: Rostrum acuminate, acarinate and with converging margins lacking marginal spines or shoulders; cervical spines present; areola narrow with 2-3 punctations in narrowest part; male with hooks on ischia of 3rd pereiopods; male first pleo

Callinectes ornatus

Portunidae

Identification: Blue Crabs of the South Atlantic Bight

Cambarus bartonii

Cambaridae

Identification: Body shape: slightly dorsoventrally flattened Coloration: variable but many dark in color (shades of brown), mostly solid coloration but some with saddle pattern and mottling Spines: cervical spines absent but may be cervical tubercle

Devil Crayfish

Cambarus diogenes

Cambaridae

Identification: Body shape: carapace vaulted Coloration: reddish-brown or grayish with bright or pastel shades of red and blue along margins and crevices Spines: lacking marginal, cephalic; cervical spines present in juveniles, but not adults Rostru

Dungeness Crab

Metacarcinus magister

Cancridae

commonly sold in restaurants and markets in w. US. the most commercially important crab in the Pacific Northwest, as well as the western states generally. In 2014, 53 million pounds worth $170 million was harvested. the annual Dungeness Crab and Seaf

Green Crab

Carcinus maenas

Portunidae

Identification: Five short notches along the rim of the carapace. Often found with another invasive species, Hemigrapsus sanguineus .

Japanese Shore Crab

Hemigrapsus sanguineus

Grapsidae

Often found with another invasive species, Carcinus maenas .

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Kisatchie Painted Crayfish

Faxonius maletae

Cambaridae

Texas and Louisiana both consider this to be a "Species of Greatest Conservation Need" (SGCN)

Knot-fingered mud crab

Panopeus lacustris

Panopeidae

Identification: It is distinguished from other member in the family by a very broad major claw forming joint (chela) with cusps of teeth in "molar area" of an immovable finger. This claw is often coalesced and worn (Abele and Kim 1986).

Libinia dubia

Epialtidae

Identification: 6 spines in median dorsal row (9 in L. emarginata ), fewer dorsal tubercles than L. emarginata

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Oklahoma cave crayfish

Cambarus tartarus

Cambaridae

Type Locality: Stansberry-January Cave System, 4 miles (6.4 km) north of Colcord, Delaware County, Oklahoma State-listed in Oklahoma as Endangered

Pacific Mole Crab

Emerita analoga

Hippidae

Identification: Carapace greenish to grey with fine stripes or speckles of light color anteriorly; pinkish laterally. First pereopod pink and white, other appendages mostly pinkish. Abdomen gray, telson white, with two pink stripes. First pair of leg

Pagurus annulipes

Paguridae

Identification: Legs banded; uniquely among northeast species

Palaemon elegans

Palaemonidae

Identification: Rostrum is distinctive: See also comments on this image:

Palaemon intermedius

Palaemonidae

Identification: Dorsal rostral teeth continue to tip of rostrum; one dorsal rostral tooth posterior to orbit, versus two in P. vulgaris .

Palaemon pugio

Palaemonidae

Identification: Dorsal rostral teeth stop well short of the tip of the rostrum; one dorsal rostral tooth posterior to orbit.

Palaemon vulgaris

Palaemonidae

Identification: Two of the dorsal rostral teeth are behind the posterior margin of the orbit, and the teeth continue to the tip of the rostrum dorsally.

Petrochirus diogenes

Diogenidae

Identification: The largest hermit crab on the Gulf Coast

Polyonyx gibbesi

Porcellanidae

Identification: According to OBIS , the only other porcellanid recorded in New England is Euceramus praelongus , which apparently looks very different.

Purple Shore Crab

Hemigrapsus nudus

Grapsidae

Identification: dorsal shell (carapace) is generally a dark purple in color, although it may be olive green or red, with white or cream markings. The color of the legs matches the color of the carapace but the white-tipped claws (chelipeds) are a lig

Red Crab

Pleuroncodes planipes

Munididae

as the most abundant species of micronekton in the California Current, large numbers occasionally wash up on beaches An onshore wind and a receding tide hasten and intensify the stranding. The number of crabs involved in the strandings may be very la

Red Rock Crab

Cancer productus

Cancridae

Identification: Can be distinguished from the Dungeness Crab by the presence of black tipped claws.

Red Swamp Crayfish

Procambarus clarkii

Cambaridae

Identification: Dark red in color, elongate chelae with tubercles. Ischia of 3rd and 4th pereiopods of males bearing hooks. Commonly cultured for food

Robust Crayfish

Cambarus robustus

Cambaridae

Identification: Body shape: very large animal; dorsoventrally flattened; wide carapace Coloration: shades of brown and red with black, orange, and yellow highlights; cream underside; mottled or bearing saddle pattern Spines: cervical spines or tuberc

Rusty Crayfish

Faxonius rusticus

Cambaridae

Identification: Can be distinguished based on the rust-colored spots on the sides of the carapace. Claws lack tubercles. Known to adversely impact macrophyte cover and abundance of certain macroinvertebrate groups (especially snails) in invaded areas

Striped Shore Crab

Pachygrapsus crassipes

Grapsidae

Identification: According to this website , this species is unique among grapsids in having transverse lines on its carapace and two teeth rather than three on the anterolateral margin of its carapace.