Lady crab

Lady crab
A molted carapace of a lady crab from Long Island, New York
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Family:	Portunidae
Genus:	Ovalipes
Species:	O. ocellatus
Binomial name
Ovalipes ocellatus (Herbst, 1799)

The lady crab or calico crab, scientific name Ovalipes ocellatus, is a species of marine swimming crab.

Distribution

The lady crab is found in the Western Atlantic Ocean from Cape Cod to Texas.

Habitat

This species of crab is most often found in sandy substrates in quite shallow water, i.e. the surf zone. Normally, this is a very difficult habitat, because of strong wave action and constantly shifting sands. This animal escapes these dangers by burrowing just beneath the sand surface. As waves toss the sand around, the crab quickly shifts position and digs back under the surface.

Description

The claws of the lady crab are not particularly large, but they are sharp. The hind pair of legs are flat and paddle-shaped for swimming when necessary. The crab grows to be 4 in (10 cm) wide.

The carapace of this crab has projections known as "frontal teeth" between the eye sockets. The teeth behind the eyes are known as marginal teeth. The lady crab has three frontal teeth, and five marginal teeth on each side.

Life habits

The lady crab feeds on live or decaying marine organisms such as fish, crabs, or clams; this means it is both a predator and a scavenger. When fish or worms pass by, it comes out of the sand and grabs the animal with its claw.

Like other swimming crabs, the lady crab does not have a very thick or rigid carapace. This means it has less protection than some other crabs, which have harder shells or exoskeletons. Because it is not very well protected, it makes up for this by its speed and camouflage.

The lady crab has compound eyes at the tip of stalks, which allows it to be aware of predators.

Reproduction and growth

As is true of most crabs, males and females are distinguished by looking at the abdominal flap beneath their bodies. The female has a wide flap in order to carry the eggs, while the males have a thin flap. Once the eggs hatch, they are planktonic. The juvenile crabs do not resemble their parents until they have molted several times over the next few weeks. As they grow, they pass through two main stages called the zoea and megalopa before becoming an adult.

The lady crab molts as it grows, like most arthropods. These crabs appear to stop molting when they reach 4 in wide. Adults that have stopped molting are often covered in growths of barnacles or seaweed.

See also

• Crustacean