''Tumidotheres maculatus'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

that lives commensally or parasitically in the

mantle cavity The mantle (also known by the Latin word pallium meaning mantle, robe or cloak, adjective pallial) is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of ...

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

. It is found along much of the western

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

and was first described by

Thomas Say Thomas Say (June 27, 1787 – October 10, 1834) was an American entomologist, conchologist, and Herpetology, herpetologist. His studies of insects and shells, numerous contributions to scientific journals, and scientific expeditions to Florida, Ge ...

in 1818.

Distribution

''Tumidotheres maculatus'' has a wide

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

in the western

, extending from the seas of

Martha's Vineyard Martha's Vineyard, often simply called the Vineyard, is an island in the U.S. state of Massachusetts, lying just south of Cape Cod. It is known for being a popular, affluent summer colony, and includes the smaller peninsula Chappaquiddick Isla ...

(

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

) to

San Matías Gulf The San Matias Gulf is an inlet of the Atlantic Ocean off the coast of Patagonia, Argentina. It is bordered by the Río Negro Province to the north and west, and the Valdes Peninsula of the Chubut Province to the south. It is "one of the largest g ...

(

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Description

There is conspicuous

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

in ''T. maculatus'' which corresponds with the differing ecology of the two sexes. Males are typically less than in

carapace A carapace is a 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 tortoises, the unde ...

width, and are able to leave the host. Females grow up to wide, and, having reached adulthood, spend their entire lives in the host.

Ecology

''Tumidotheres maculatus'' is an

endosymbiont An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualism (biology), mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), whi ...

of molluscs; it is unclear whether the host is harmed by the crabs presence, that is whether the relationship is

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit f ...

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

. It is associated with a wide range of mollusc hosts, most of which are

bivalves Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...

. They include ''

Argopecten irradians ''Argopecten irradians'', formerly classified as '' Aequipecten irradians'', common names Atlantic bay scallop, bay scallop, and blue-eyed scallop, is a species of scallop in the family Pectinidae. An edible saltwater clam, it is native to the ...

'', ''

Atrina rigida ''Atrina rigida'', commonly called the rigid pen shell, is a species of bivalve mollusc in the family (biology), family Pinnidae. Description The rigid shell has a pair of thick spiny valves held together by ligaments that run along the entire ...

'', '' Modiolus americanus'', ''

Mytilus edulis The blue mussel (''Mytilus edulis''), also known as the common mussel, is a medium-sized edible marine (ocean), marine bivalve mollusc in the family (biology), family Mytilidae, the only extant family in the order (biology), order Mytilida, known ...

'' and '' Flexopecten felipponei''. It has also been found in a

tunicate Tunicates are marine invertebrates belonging to the subphylum Tunicata ( ). This grouping 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 ...

of the genus '' Molgula'', in the tubes of the tubeworm ''

Chaetopterus variopedatus ''Chaetopterus variopedatus'' is a species of parchment worm, a marine polychaete in the family Chaetopteridae. It is found worldwide. However, recent discoveries from molecular phylogeny analysis show that ''Chaetopterus variopedatus'' sensu Har ...

'' and on the asteroid (

starfish Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

) ''

Asterias rubens The common starfish, common sea star or sugar starfish (''Asterias rubens'') is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30 c ...

''. In molluscan hosts, ''T. maculatus'' uses its legs to cling to the gills of its host, and feeds on strands of food aggregated by the host. Reported rates of

infestation Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology In general, the term "infestation" refers to parasitic diseases caused by animals su ...

of ''T. maculatus'' on mollusc hosts vary widely, from 0%–20% on ''

'' at St. Joseph Bay,

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

, to 97.6% on ''

'' at Quicks Hole,

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

Taxonomy

''Tumidotheres maculatus'' was first described by

in 1818, under the name ''Pinnotheres maculatus''. It was transferred to the new genus '' Tumidotheres'', alongside '' T. margarita'' by Ernesto Campos in 1989. It may be the species referred to by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

as ''Cancer parasiticus'' in his 1763 work ''

Centuria Insectorum file:Centuria Insectorum.png, The first page of ''Centuria Insectorum'', as included in ''Amoenitates Academicæ'' ' (Latin, "one hundred insects") is a 1763 Taxonomy (biology), taxonomic work by Carl Linnaeus, and defended as a thesis by Boas Jo ...

'', and the one he called ''Cancer pinnophylax'' in the 1767

12th edition 1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sp ...

of ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

''.

References

External links

* {{Taxonbar, from=Q3934128 Pinnotheroidea Crabs of the Atlantic Ocean Crustaceans described in 1818 Taxa named by Thomas Say