Shame-faced Box Crab, Calappa convexa

Shame-faced Box Crab, Calappa convexa. Crab provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2011. Size 11.9 cm (4.7 inches) x 8.3 cm (3.3 inches).

General information: The Shame-faced Box Crab, Calappa convexa, is one of thirty-nine members of the Calappidae Family or Box Crabs known in Mexico as cangrejo cajeta bolas. It is known locally as cangrejo cajeta bola. Reproduction occurs throughout the year.

Identification:  The Shame-faced Box Crab has mouth parts that taper toward the rear of the body and form a triangle. The shell (carapace) is broader than it is long and a large laterally directed tooth originates at the widest part. The common name of the Shamed-face Box Crab is derived from the pair of equal sized large claws that normally cover the face. The carapace as well as the claws are covered with low tubercles. The chelipeds are tightly held against the carapace giving it a globular appearance. They are a dull red color with fine yellowish white dots. The Shamed-face Box Crab reach a maximum of 15 cm (5.9 inches) in width.

Habitat and Range: In Mexican waters the Shamed-faced Box Crab is found from Magdalena Bay southward along the southwest coast of Baja, throughout the Sea of Cortez and along the coast of the mainland south to Guatemala. Their claws have a limited commercial market as it requires 100 adults to produce 6.8 kg (15 lbs) of claws with the balance of the crab being discarded. They are found over sandy and mud bottoms at depths ranging between 18 m (60 feet) and 122 m (400 feet).

Diet: The Shame-faced Box Crab is a nocturnal carnivore primarily eating marine mollusks, using their strong claws to crack open their hard shells, other small invertebrates and detritus.

Conservation Status: From a conservation perspective the Shamed-faced Box Crab has not been formally evaluated. However, they are common and of limited interest to most and should be considered to be of Least Concern.

Synonyms:  Calappa xantusiana