Ovalipes ocellatus

Ovalipes ocellatus, commonly known as the lady crab,^[a] oscellated crab,^[b] or calico crab,^[6][c] is a species of crab in the family Ovalipidae.^[2][8]

Ovalipes ocellatus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Family:	Ovalipidae
Genus:	Ovalipes
Species:	O. ocellatus
Binomial name
Ovalipes ocellatus (Herbst, 1799) [1]
Synonyms [2]
Cancer ocellatus Herbst, 1799 Platyonichus ocellatus (Herbst, 1799) Portunus pictus Say, 1817

Description

The carapace of O. ocellatus is slightly wider than long, at 8.9 centimetres (3.5 in) wide,^[6] and 7.5 cm (3.0 in) long.^[9] The carapace is yellow-grey^[9] or light purplish,^[6] with "leopardlike clusters of purple dots".^[9] It exhibits a limited iridescence as a form of signalling.^[10]

Taxonomy

Ovalipes ocellatus is commonly known as the lady crab,^[a] oscellated crab,^[b] or calico crab.^[6] It was first described in 1799 by naturalist Johann Friedrich Wilhelm Herbst, who placed it into the genus Cancer.^[1][2] In 1898, carcinologist Mary Jane Rathbun moved the species to her new genus Ovalipes.^[11] O. ocellatus is part of a distinct group of Ovalipes which also includes O. floridanus, O. iridescens, O. molleri, and O. stephensoni.^[12][10][d] O. ocellatus is almost identical to O. floridanus, which lives in the Gulf of Mexico, but can be separated from the sympatric O. stephensoni by purple spots which O. stephensoni lacks.^[9] The following cladogram based on morphology shows the relationship between O. catharus and the other extant species of Ovalipes:^[10][e]

Ovalipes	Ovalipes georgei                               Ovalipes australiensis       Ovalipes punctatus       Ovalipes elongatus       Ovalipes trimaculatus       Ovalipes catharus                               Ovalipes ocellatus       Ovalipes stephensoni       Ovalipes floridanus             Ovalipes iridescens       Ovalipes molleri

Distribution

The distribution of Ovalipes ocellatus extends along North America's Atlantic coast from Canada to Georgia.^[9] O. ocellatus is "probably the only Ovalipes species common north of Virginia", being replaced by Ovalipes stephensoni to the south.^[14]

Diet

The diet of Ovalipes ocellatus consists predominantly of bivalves, crustaceans including other crabs, polychaetes, cephalopods, and gastropods.^[15][16] It rarely feeds on fish.^[15]

Life cycle

Ovalipes ocellatus has five zoeal (larval) stages, lasting a total of 18 days at 25 °C (77 °F) and a salinity of 30‰, and 26 days at 20 °C (68 °F) and 30‰.^[17]

Ecology

Ovalipes ocellatus often buries itself in the sand.^[6]

Ovalipes ocellatus is nocturnal and often buries itself in the sand.^[6][9] It has been described as "vicious" and "the crab most likely to pinch a wader's toes".^[9]

Notes

1. Sometimes "northern lady crab"^[3][4]
2. Sometimes "ocellate lady crab"^[5]
3. The nickname "calico crab" is shared with Hepatus epheliticus.^[7]
4. This group – one of two – is distinguished from the rest of Ovalipes by features such as iridescence, lack of a tooth at the top of its orbit, and a carina ending in a spine on the outer wrist.^[13]
5. Ovalipes itself sits within the monogeneric family Ovalipidae.^[8]