The Pinnotheridae are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of tiny soft-bodied

crabs 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 ...

that live commensally in the mantles of certain

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusc 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 species of molluscs are recognized. The number of fossil species is esti ...

s (and the occasional large

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc species in genera such as ''

Strombus ''Strombus'' is a genus of medium to large sea snails, marine gastropod molluscs in the family Strombidae, which comprises the true conchs and their immediate relatives. The genus ''Strombus'' was named by Swedish Naturalist Carl Linnaeus in 175 ...

'' and ''

Haliotis ''Haliotis'', common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of ''Haliotis''. The genus consists of small to very large, edible, ...

''). '' Tunicotheres moseri'' is commensal with a

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...

. The earliest

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s attributable to the Pinnotheridae date from the

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretaceous� ...

Genera and species

This is a comprehensive list of species in the family, as of 2008: ;''Abyssotheres'' ;'' Afropinnotheres'' ;'' Alarconia'' ;'' Alain'' *''

Alain crosnieri Alain may refer to: People * Alain (given name), common given name, including list of persons and fictional characters with the name * Alain (surname) * "Alain", a pseudonym for cartoonist Daniel Brustlein * Alain, a standard author abbreviation u ...

'' *''

Alain raymondi Alain may refer to: People * Alain (given name), common given name, including list of persons and fictional characters with the name * Alain (surname) * "Alain", a pseudonym for cartoonist Daniel Brustlein * Alain, a standard author abbreviation u ...

jewel-box pea crab ''Gemmotheres'' also known as the jewel-box pea crab, is a monotypic genus of pea crab, which was erected in 1996 to hold the species ''Gemmotheres chamae'' (formerly ''Pinnotheres chamae''). The species lives as a commensal of the corrugate jew ...

Pinnixa chaetopterana ''Pinnixa chaetopterana'', the tube pea crab, is a small decapod crustacean that lives harmlessly within the tube of the polychaete worm, ''Chaetopterus variopedatus''. Description ''P. chaetopterana'' is a tiny, soft-bodied crab. The bodies o ...

'' — tube pea crab *'' Pinnixa chiloensis'' *'' Pinnixa costaricana'' *'' Pinnixa cylindrica'' *'' Pinnixa darwini'' *'' Pinnixa eburna'' *''

Pinnixa faba ''Pinnixa faba'', known as the pea crab, mantle pea crab or large pea crab, is a pea crab which lives harmlessly within a large edible clam. This species is a symbiont of '' Tresus capax'' and '' Tresus nuttallii'' in its mature stage. Descript ...

pea crab The pea crab, ''Pinnotheres pisum'', is a small crab in the family Pinnotheridae that lives as a parasite in oysters, clams, mussels, and other species of bivalves. Description Pea crabs are small crustaceans about the size of a pea or dime, wit ...

Tumidotheres maculatus ''Tumidotheres maculatus'' is a species of crab that lives commensally or parasitically in the mantle cavity of molluscs. It is found along much of the western Atlantic Ocean and was first described by Thomas Say in 1818. Distribution ''Tumi ...

'' — squatter pea crab *'' Tumidotheres margarita'' ;''Tunicotheres'' *'' Tunicotheres moseri'' — ascidian pea crab ;'' Viridotheres'' *'' Viridotheres buergeri'' *'' Viridotheres gracilis'' *'' Viridotheres lillyae'' *'' Viridotheres marionae'' *'' Viridotheres otto'' *'' Viridotheres viridis'' ;''Visayeres'' *'' Visayeres acron'' ;''Waldotheres'' *'' Waldotheres mccainae'' ;''Xanthasia'' *'' Xanthasia murigera'' ;'' Zaops'' *'' Zaops geddesi'' *'' Zaops ostreus''

External links

{{Authority control Crabs Danian first appearances Taxa named by Wilhem de Haan Extant Danian first appearances Decapod families