Ovalipes ocellatus

The carapace of O. ocellatus is slightly wider than long, at {{convert|8.9|cm}} wide,{{sfn|Pollock|1998|p=264}} and {{convert|7.5|cm|abbr=on}} long. The carapace is yellow-grey or light purplish,{{sfn|Pollock|1998|p=264}} with "leopardlike clusters of purple dots". It exhibits a limited iridescence as a form of signalling.{{sfn|Parker|Mckenzie|Ahyong|1998|p=866}}

Ovalipes ocellatus is commonly known as the lady crab,{{efn|name=Northern lady crab}} oscellated crab,{{efn|name=Ocellate lady crab}} or calico crab.{{sfn|Pollock|1998|p=264}} It was first described in 1799 by naturalist Johann Friedrich Wilhelm Herbst, who placed it into the genus Cancer.{{sfn|Herbst|1799|pp=61–62}} In 1898, carcinologist Mary Jane Rathbun moved the species to her new genus Ovalipes.{{sfn|Rathbun|1898|p=597}} O. ocellatus is part of a distinct group of Ovalipes which also includes O. floridanus, O. iridescens, O. molleri, and O. stephensoni.{{sfn|Stephenson|Rees|1968|pp=214, 245}}{{sfn|Parker|Mckenzie|Ahyong|1998|p=866}}{{Efn|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.{{sfn|Stephenson|Rees|1968|pp=213, 247–248}}}} 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.{{cite book |title=A Field Guide to Southeastern and Caribbean Seashores: Cape Hatteras to the Gulf Coast, Florida, and the Caribbean|series=Peterson Field Guides|last=Kaplan|first=Eugene H.|editor=Roger Tory Peterson|edition=2nd|publisher=Houghton Mifflin Harcourt |year=1999 |isbn=978-0-395-97516-9|chapter=Lady crab Ovalipes ocellatus|pages=322}} The following cladogram based on morphology shows the relationship between O. catharus and the other extant species of Ovalipes:{{sfn|Parker|Mckenzie|Ahyong|1998|p=866}}{{Efn|Ovalipes itself sits within the monogeneric family Ovalipidae.{{sfn|Poore|Ahyong|2023|pp=695–696}}}}

{{Ovalipes cladogram}}

The distribution of Ovalipes ocellatus extends along North America's Atlantic coast from Canada to Georgia. O. ocellatus is "probably the only Ovalipes species common north of Virginia", being replaced by Ovalipes stephensoni to the south.{{cite book |last=Johnson |first=William S. |last2=Allen |first2=Dennis M. |year=2005 |title=Zooplankton of the Atlantic and Gulf coasts: a guide to their identification and ecology |publisher=Johns Hopkins University Press |isbn=978-0-8018-8019-3 |chapter=Swimming (Portunid) crabs |pages=220–222}}

The diet of Ovalipes ocellatus consists predominantly of bivalves, crustaceans including other crabs, polychaetes, cephalopods, and gastropods.{{sfn|Stehlik|1993|pp=727–729}}{{sfn|Ropes|1989|p=201}} It rarely feeds on fish.{{sfn|Stehlik|1993|pp=727–729}}

Ovalipes ocellatus has five zoeal (larval) stages, lasting a total of 18 days at {{convert|25|C|F}} and a salinity of 30‰, and 26 days at {{convert|20|C|F}} and 30‰.{{cite book

|title=Larvae of anomuran and brachyuran crabs of North Carolina: a guide to the described larval stages of anomuran (families Porcellanidae, Albuneidae, and Hippidae) and brachyuran crabs of North Carolina, U.S.A. |series=Volume 1 of Crustaceana monographs |last=Bullard |first=Stephan Gregory |publisher=Brill |year=2003 |isbn=978-90-04-12841-5 |chapter=Ovalipes ocellatus (Herbst, 1799) |pages=29–30}}

File:Ovalipes ocellatus partially buried in sand dorsal.jpg

Ovalipes ocellatus is nocturnal and often buries itself in the sand.{{sfn|Pollock|1998|p=264}} It has been described as "vicious" and "the crab most likely to pinch a wader's toes".

{{Notelist}}

{{Reflist}}

{{Refbegin|30em}}

• {{Cite book|last=Herbst|first=Johann Friedrich Wilhelm|author-link=Johann Friedrich Wilhelm Herbst|title=Versuch einer Naturgeschichte der Krabben und Krebse &c. &c.|trans-title=Attempt at a Natural History of Crabs and Crustaceans &c. &c.|lang=de|publisher=Gottlieb August Lange|location=Berlin and Stralsund|year=1799|edition=First|url=https://archive.org/details/versucheinernatu03herb|via=the Internet Archive}}
• {{Cite journal |last=Rathbun |first=Mary Jane |year=1898 |title=The Brachyura collected by the U. S. Fish Commission steamer Albatross on the voyage from Norfolk, Virginia, to San Francisco, California, 1887-1888 |journal=Proceedings of the United States National Museum |volume=21 |issue=1162 |pages=567–616 |url=http://biostor.org/reference/3351 |author-link=Mary J. Rathbun|doi=10.5479/si.00963801.21-1162.567}}
• {{Cite book |last=Voss|first=Gilbert L.|title=Seashore Life of Florida and the Caribbean|publisher=Dover Publications|year=2002|orig-year=1980|isbn=0-486-42068-X}}
• {{Cite book|last=Ruppert|first=Edward|last2=Fox|first2=Richard|title=A Guide to Common Shallow-Water Invertebrates of the Southeastern Atlantic Coast|year=1988|chapter=Arthropoda|publisher=University of South Carolina Press|isbn=0-87249-534-5}}
• {{Cite journal|last=Ropes|first=John W.|title=The Food Habits of Five Crab Species at Pettaquamscutt River, Rhode Island|year=1989|journal=Fishery Bulletin|volume=87|issue=1|pages=197–204|url=https://spo.nmfs.noaa.gov/sites/default/files/pdf-content/1989/871/ropes.pdf|archive-url=https://web.archive.org/web/20240530025823/https://spo.nmfs.noaa.gov/sites/default/files/pdf-content/1989/871/ropes.pdf|archive-date=30 May 2024|url-status=live|access-date=30 January 2025}}
• {{Cite journal|last=Stehlik|first=Linda L.|title=Diets of the Brachyuran Crabs Cancer Irroratus, C. Borealis, and Ovalipes Ocellatus in the New York Bight|date=October 1993|journal=Journal of Crustacean Biology|volume=13|issue=4|pages=723–735|doi=10.1163/193724093X00291|jstor=1549103}}
• {{Cite journal|last1=Parker|first1=Andrew R.|last2=Mckenzie|first2=David R.|last3=Ahyong|first3=Shane T.|author-link3=Shane T. Ahyong|title=A unique form of light reflector and the evolution of signalling in Ovalipes (Crustacea: Decapoda: Portunidae)|journal=Proceedings of the Royal Society B: Biological Sciences|date=22 May 1998|volume=265 |issue=1399 |pages=861–867 |doi=10.1098/rspb.1998.0371|pmc=1689053}}
• {{Cite book|last=Pollock|first=Leland W.|title=A Practical Guide to the Marine Animals of Northeastern North America|year=1998|publisher=Rutgers University Press|isbn=978-0-8135-2399-6}}
• {{Cite book|last1=Poore|first1=Gary C.B.|last2=Ahyong|first2=Shane T.|author-link2=Shane T. Ahyong|title=Marine Decapod Crustacea: A Guide to Families and Genera of the World|publisher=CRC Press|year=2023|isbn=978-1-4863-1178-1|lccn=2021388782|doi=10.1071/9781486311798}}

{{Refend}}

• {{Commons category-inline|2=Ovalipes ocellatus}}
• [https://www.si.edu/object/3d/ovalipes-ocellatus:3635a529-88ed-44c8-9554-2b80e813a5f7 3D model] from the Smithsonian Institution

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Category:Portunoidea

Category:Crabs of the Atlantic Ocean

Category:Crustaceans described in 1799