Libinia dubia

H. Milne Edwards, 1834

longnose spider crab

Libinia dubia, commonly known as the longnose spider crab, is a brachyuran decapod in the Epialtidae. It is native to shallow waters along the eastern coast of North America, ranging from Cape Cod to southern Texas, including the Bahamas and Cuba. The has been introduced to the central Mediterranean Sea, where it was first recorded off Tunisia in the late 1900s. It exhibits distinctive camouflage by attaching and to hooked setae on its , and is known to associate with jellyfish and sea turtles.

Libinia dubia by (c) Mary Spilman, some rights reserved (CC BY), uploaded by Mary Spilman. Used under a CC-BY license.

Image from page 126 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14598329499) by Internet Archive Book Images. Used under a No restrictions license.

Image from page 127 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14598330019) by Internet Archive Book Images. Used under a No restrictions license.

Pronunciation

How to pronounce Libinia dubia: /lɪˈbɪniə ˈdubɪə/

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Identification

Distinguished from Libinia emarginata by margin spine count: L. dubia has approximately six spines per side versus nine in L. emarginata. The forked rostrum and circular carapace with hooked, velcro-like setae are diagnostic. Size range and overlap with L. emarginata necessitate careful spine counting for positive identification.

Images

Habitat

Shallow marine waters, typically at depths down to 50 meters. In the Indian River Lagoon, occur on sandy bottoms while juveniles inhabit seagrass meadows. Collected from mud and seagrass beds in Tampa Bay. Benthic, slow-moving, and in activity pattern.

Distribution

Native range: eastern seaboard of the United States from Cape Cod, Massachusetts to southern Texas; includes Cuba and the Bahamas. Introduced established in the central Mediterranean Sea, specifically off the coast of Tunisia (first recorded late 1900s, with confirmed breeding population in Gulf of Gabès).

Seasonality

Reproductive activity peaks in spring (May in Mediterranean ), with spawning season extending March through July in introduced range. Sexual rest phase occurs October–November in females, September–November in males (Mediterranean data). activity pattern observed.

Diet

Scavenger and ; consumes seaweeds in seagrass meadows.

Host Associations

Stomolophus meleagris - commensalJuveniles and frequently found living inside bells of cannonball jellyfish; crabs may gain protection from and access to food, while benefit to jellyfish is unclear and tissues may be nibbled.
Caretta caretta - epibiontSometimes lives as epibiont on loggerhead turtle .

Life Cycle

Undergoes terminal ; larger and older individuals reach terminal molt stage. Larval development includes two zoeal stages and one megalopal (post-larval) stage, followed by settlement and to crab form. In Mediterranean , first gonadal sexual maturity occurs earlier in females than males; increases with crab size and weight.

Behavior

activity pattern. Exhibits specialized using first pereiopods (chelipeds) and third maxillipeds, with actions including scraping, picking, and brushing. Grooming time budget is highest in isolated individuals (5.22%) and decreases dramatically in presence of conspecifics (0.67%) due to social interactions. Ovigerous females observed flapping , possibly to groom and aerate developing . occurs.

Ecological Role

Prey for predatory fishes including pinfish (Lagodon rhomboides), gag grouper (Mycteroperca microlepis), and oyster toadfish (Opsanus tau). As in Mediterranean, has potential for establishment and spread with possible impacts on native .

Human Relevance

agent potential through on pestiferous organisms; subject of scientific study regarding dynamics and . Not commercially harvested.

Similar Taxa

Libinia emarginataOverlapping distribution and similar circular ; distinguished by nine marginal spines per side versus six in L. dubia.

More Details

Camouflage and Decorating Behavior

Attaches pieces of seaweed and other organisms to hooked setae on , rostrum, and legs for camouflage. Along the U.S. East Coast, preferentially selects chemically noxious brown Dictyota menstrualis and sun sponge Hymeniacidon heliophila; recognition of D. menstrualis is geographically variable and absent where the alga does not occur. Larger individuals abandon decorating as carapace becomes too large for to ingest.

Grooming Morphology

Possesses fourteen distinct setal types on appendages, including serrate, pappose, simple, cuspidate, papposerrate, and canoe setae. Maxillipodal epipods in gill chamber remain free of fouling, indicating efficient debris removal before water enters gill chamber. Cheliped contains only pappose setae and is the only appendage reaching decorating setae, suggesting limited grooming efficacy for decorated surfaces.