Two Horn Box Crab, Shame-faced Crab – Calappa bicornis

, Two Horn Box Crab, Shame-faced Crab, Calappa bicornis
Depth: 17 - 150 m

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Amvrakikos Gulf, Andaman Sea, Arabian Sea, Aral Sea, Arctic Ocean, Atlantic Ocean, Baltic Sea, Barents Sea, Bay of Bengal, Bay of Biscay, Beaufort Sea, Bering Sea, Black Sea, Bohai Sea, Cantabrian Sea, Celtic Sea, Chukchi Sea, Coral Sea, Dead Sea, English Channel, German Bight, Great Barrier Reef, Greenland Sea, Gulf of Aden, Gulf of Fonseca, Gulf of Maine, Gulf of Mexico, Gulf of Saint Lawrence, Halmahera Sea, Iberian Sea, Indian Ocean, Java Sea, Korinthiakos Gulf, Labrador Sea, Levantine Sea, Lingayan Gulf, Mediterranean Sea, Moro Gulf, Okhotsk Sea, Pacific Ocean, Pagassitikos Gulf, Salish Sea, Saronikos Gulf, Scotia Sea, Sea of Azov, Sea of Marmara, Siberian Sea, South China Sea, Southern Ocean, Thermaikos Gulf

The Two Horn Box Crab, Shame-faced Crab, scientifically known as Calappa bicornis, is a captivating crustacean that inhabits the sandy seafloors of the world’s oceans. Its distinctive appearance, characterized by a pair of prominent horns projecting from the carapace, has earned it the name “Two Horn Box Crab”. This intriguing crab is a fascinating example of marine biodiversity, showcasing adaptations that allow it to thrive in its unique habitat.

Description & Characteristics

The Calappa bicornis is a relatively large crab, reaching a maximum size of around 15 centimeters in width. The carapace, or shell, is broad and flattened, giving the crab a boxy appearance. It exhibits a distinctive color pattern, often featuring a mottled brown or reddish-brown hue, interspersed with lighter patches. The most striking feature of the Calappa bicornis is the presence of two large, pointed horns, located just above its eyes. These horns are believed to play a role in defense, deterring potential predators. The crab also possesses a pair of large, powerful claws, used for capturing and manipulating prey. The abdomen, or underside, of the crab is folded neatly underneath the carapace, contributing to its box-like shape.

Habitat and Occurrence

The Two Horn Box Crab, Shame-faced Crab (Calappa bicornis) is a denizen of the subtidal, sublittoral, and infralittoral zones of the oceans. This means it is found in the depths below the intertidal zone, extending down to the shelf edge, approximately 200 meters below the surface. These zones are characterized by their sandy seafloors, providing the crab with a suitable environment for burrowing and foraging. The Calappa bicornis is commonly encountered in neritic waters, which are those situated above the continental shelf.

Taxonomy

The species Calappa bicornis belongs to the Class: Malacostraca, Order: Decapoda, and Family: Calappidae. This classification places it within a group of crustaceans characterized by their ten legs, including the iconic claws. The Family Calappidae, to which the Calappa bicornis belongs, encompasses a diverse range of crabs, many of which are known for their flattened carapaces and burrowing habits.

Feeding

The Calappa bicornis is a carnivorous crab with a predatory lifestyle. Its diet primarily consists of snails, which it captures using its strong claws. The crab’s powerful pincers allow it to crack open the snail’s shell, granting access to the soft flesh within. The Calappa bicornis is an opportunistic feeder, readily consuming other small invertebrates, including worms, crustaceans, and fish, that it encounters in its habitat.

Associated Species

Image References

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