Cardisoma crassum

Invasion History

First Galapagos Record: 1993

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General Invasion History:

Cardisoma crassum, the Mouthless or Blue Land Crab, is native to the tropical Eastern Pacific, from the Gulf of California to Peru.  Adults are mostly terrestrial, but favor the margins of aquatic habitats, including beaches, mangroves, riverbanks, etc., (Bright 1966; von Prahl and Manjares 1984).  Adults return to estuaries and the oceans for spawning.  Eggs hatch into a zoea larva, which develops into a megalopa which settles and matures into an amphibious juvenile. 

Invasion History in the Galapagos:

Bright (1966) listed C. crassum for the Galapagos Islands, but without supporting evidence.  The first documented introduction of this crab occurred in 1993 on Santa Cruz Island. 'It was introduced when some living crabs reportedly brought to a hotel in Puerto Ayora to prepare a traditional crab dish for the captain of a tour boat, escaped' (Hickman and Zimmerman 2000); 'the date was 1993' (Rodrigo H. Bustamante, pers. comm., 1997, cited by Carlton et al. 2019). The crab has since spread to Isabella and Santiago Islands (Carlton et al. 2019). 

Invasion history elsewhere in the world:

Invasion history for Elsewhere in the World has not been summarized for this species at this time.

Description

Cardisoma crassum (Mouthless Crab, Blue Land Crab) is a terrestrial crab that inhabits dry and marginal wetland habitats, including the margins of mangroves, transitional forests, riverbanks, beaches, etc., but spawns in estuaries and the ocean (Bright 1966; von Prahl and Manjarres 1984; Vazquez-Lopez et al. 2017). The carapace is oval and wider than it is long. In the genus Cardisoma, the interobital distance (distance between the eyes) is more than half the width of the carapace. The carapace is bordered by a lateral ridge. The merus (2nd segment) of the claw has a notch near the tip, and the dactyls of the legs are spinous. The legs are 'conspicuously hairy’. The male gonopod is flattened and hairy, with a long spiral tip.  The carapace is deep blue, and the dactyls of the legs are red. The large chela is pale yellow to dirty white. The underside is creamy-white. A typical male was 105 mm wide, and 132.3 mm wide. A female was 61 mm long, and 75 mm wide (Bright 1966).

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Taxonomy

Ecology

General:

Cardisoma crassum (Mouthless Crab, Blue Land Crab) is a terrestrial crab inhabits dry and wetland habitats, including the margins of mangroves, transitional forests, river banks, beaches, etc., but spawns in estuaries and the ocean (Bright 1966; von Prahl and Manjarres 1984). 
 
Adults males and females of Cardisoma crassum live on land, often on the margins of wetlands, but sometimes a long distance from the sea. The adults migrate to estuaries and the ocean where spawning takes place. The fertilized eggs are incubated under the female's abdomen as in other crabs. The eggs hatch into a 1st zoea, which is planktonic (Vazquez-Lopez et al. 2017). Full development is undescribed for C. crassum, but the West African C. crassum goes through 6 zoea stages, and a megalopa stage before it assumes the 1st crab stage (Cuesta and Anger 2005). 
 
Adult Cardisoma crassum inhabit a variety of terrestrial and semiterrestrial habitats including mangroves, forests, swamps, open fields, and roadsides. They dig deep burrows with multiple entrances (Bright 1966).

Food:

Mangrove leaves, other plants, dead animals

Consumers:

Birds, reptiles, mammals

Trophic Status:

Omnivore

Omni

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Habitats

General Habitat	Mangroves	None
General Habitat	Terrestrial	None
General Habitat	Swamp	None
General Habitat	Grass Bed	None
General Habitat	Salt-brackish marsh	None
General Habitat	Marinas & Docks	None
Salinity Range	Mesohaline	5-18 PSU
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Tidal Range	Mid Intertidal	None
Tidal Range	High Intertidal	None
Tidal Range	Terrestrial	None
Vertical Habitat	Epibenthic	None

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Life History

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Tolerances and Life History Parameters

Minimum Salinity (‰)	0	None
Maximum Salinity (‰)	35	Adults mostly terrestrial, but moves around margins of mangroves, rivers and other wetlands
Maximum Reproductive Salinity	35	Marine spawning and larval develop,emt
Maximum Width (mm)	132	Carapace width male; female 61 mm (Bright 1966), single specimens
Broad Temperature Range	None	Tropical
Broad Salinity Range	None	Limnetic-Euhaline

General Impacts

Cardisoma crassum, the Mouthless or Blue Land Crab has no reported impacts in the Galapagos Islands. However, it has no native equivalents on the islands. 

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References

Alemán, Solange; Ordinola, Elmer (2017) [Expansion of southern distributional range of Ucides occidentalis (Decapoda: Ucididae) and Cardisoma crassum (Decapoda: Gecarcinidae], Revista Peruana de Biología 24(1): 107-110

Bright, Donald B. (1966) The Land Cloabs of Costa Rica, Revista Biologia Tropica 14(2): 182-203

Carlton, James T.; Keith, Inti; Ruiz, Gregory M. (2019) Assessing marine bioinvasions in the Galápagos Islands: implications for conservation biology and marine protected areas, Aquatic Invasions 14(1): 1-20

Cuesta, Jose A.; Anger, Klaus (2005) Larval morphology and salinity tolerance of a land crab from West Africa, Cardisoma armatum (Brachyura: Grapsoidea: Gecarcinidae), Journal of Crustacean Biology 25(4): 640-654

Keith, Inti; , Dawson, Terence P.; Collins, Ken J.; Campbell, Marnie L. (2016) Marine invasive species: establishing pathways, their presence and potential threats in the Galapagos Marine Reserve, Pacific Conservation Biology 22: 377-385

Manrique, Fernando A. (1981) Two new records for land crabs in the Gulf of California (Brachyura, Gecarcinidae), Crustaceana 41(2): 216-217

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/



von Prahl , Henry; Manjarres, Gustavo (1984) Gecarcindae crabs (Crustacea: Gecarcidnidae) of Colombia, Cladasia 14(66): 156-166

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