''Ovalipes ocellatus'', known as the lady crab, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

from eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Other names for it include the leopard crab or Atlantic leopard crab due to the leopard-like rosette patterns on its shell, the calico crab (not to be confused with ''

Hepatus epheliticus ''Hepatus epheliticus'', known by various names, including the calico crab (not to be confused with ''Ovalipes ocellatus'') and Dolly Varden crab, is a species of crab. It lives in shallow water in the western Atlantic Ocean from the Chesapeake ...

''), or ocellated crab. It has a shell long and only slightly wider, which is covered in clusters of purple spots. It occurs from

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

, and lives mainly on molluscs, such as the

Atlantic surf clam The Atlantic surf clam (''Spisula solidissima''), also called the bar clam, hen clam, skimmer or simply sea clam, is a very large, edible, saltwater clam or marine bivalve mollusk in the family Mactridae. It is commonly found in the western Atla ...

Taxonomy

''O. ocellatus'' was first described by

Johann Friedrich Wilhelm Herbst Johann Friedrich Wilhelm Herbst (1 November 1743 – 5 November 1807) was a German naturalist and entomologist from Petershagen, Minden-Ravensberg. He served as a chaplain in the Prussian army. His marriage in Berlin, 1770, with Euphrosyne Luise ...

in 1799, as ''Cancer ocellatus''. In 1898, Mary Jane Rathbun moved the species to her new genus ''

Ovalipes ''Ovalipes'' is a genus of crabs in the family (biology), family Ovalipidae, containing 11 extant species: *''Ovalipes australiensis'' Stephenson & Rees, 1968 *''Ovalipes catharus'' (White, 1843) *''Ovalipes elongatus'' Stephenson & Rees, 1968 *' ...

''.

Description

The

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

of ''O. ocellatus'' is slightly wider than long, at wide, and long. This distinguishes it from other crabs in the family

Portunidae Portunidae is a family of crabs which contains the swimming crabs. Description Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong ...

, which often have elongated lateral spines. The carapace is yellow-grey or light purplish, with "leopardlike clusters of purple dots", and 3–5 spines along the edge behind each eye. ''O. ovalipes'' is almost identical to '' O. floridanus'', which lives in the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

, but can be separated from the

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

'' O. stephensoni'' by the purple spots, which ''O. stephensoni'' lacks.

Distribution

The distribution of ''O. ocellatus'' extends from

. ''O. ocellatus'' is "probably the only ''Ovalipes'' species common north of Virginia", being replaced by ''

Ovalipes stephensoni ''Ovalipes'' is a genus of crabs in the family Ovalipidae, containing 11 extant species: *''Ovalipes australiensis'' Stephenson & Rees, 1968 *''Ovalipes catharus'' (White, 1843) *''Ovalipes elongatus'' Stephenson & Rees, 1968 *''Ovalipes floridan ...

'' to the south.

Life cycle

''O. ocellatus'' has five

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

l stages, lasting a total of 18 days at and a

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

of 30

‰ Per mille (from Latin , "in each thousand") is an expression that means parts per thousand. Other recognised spellings include per mil, per mill, permil, permill, or permille. The associated sign is written , which looks like a percent sig ...

, and 26 days at and 30‰.

Ecology

''O. ocellatus'' is a nocturnal predator, which often buries itself in the sand. It has been described as "vicious" and "the crab most likely to pinch a wader's toes". It feeds mostly on

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil sp ...

, particularly the

''Spisula solidissima''.

References

{{Taxonbar, from=Q7113228 Portunoidea Crustaceans of the Atlantic Ocean Crustaceans described in 1799