''Tumidotheres maculatus'' 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 ...

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 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 ...

. It is found along much of the western

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

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 Northeastern United States, located south of Cape Cod in Dukes County, Massachusetts, known for being a popular, affluent summer colony. Martha's Vineyard includes the s ...

(

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

) 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 ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

Description

There is conspicuous

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

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

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 ...

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 any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...

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 fro ...

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

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

bivalves 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 ...

. They include ''

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

'', '' Atrina rigida'', '' 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 mussels. Blue mussels are subject to commercial use and intensiv ...

'' and ''

Flexopecten felipponei ''Flexopecten felipponei'' is a species of saltwater scallop, a marine bivalve mollusk in the family Pectinidae, the scallops. Original description The species ''Flexopecten felipponei'' was originally described as ''Pecten'' (''Chlamys'') ...

''. It has also been found in 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 ...

of the genus ''

Molgula ''Molgula'', or sea grapes, are very common, globular, individual marine tunicates roughly the size of grapes.Sanamyan, K.; Monniot, C. (2012). Molgula Forbes, 1848. In: Noa Shenkar, Arjan Gittenberger, Gretchen Lambert, Marc Rius, Rosana Moreira ...

'', 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 Ha ...

'' and on the asteroid (

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

) ''

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 ...

''. 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 St. Joseph Bay is a bay on the Gulf Coast of the U.S. state of Florida. The bay is located in Gulf County between Apalachicola and Panama City. Port St. Joe is located on St. Joseph Bay. St. Joseph Bay is bounded on the east by the mainland, o ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, to 97.6% on ''

'' at Quicks Hole,

Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...

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 his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

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

Centuria Insectorum The first page of ''Centuria Insectorum'', as included in ''Amoenitates Academicæ'' ' (Latin, "one hundred insects") is a 1763 taxonomic work by Carl Linnaeus, and defended as a thesis by Boas Johansson; which of the two men should for taxonomi ...

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

12th edition 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. I ...

of ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

''.

References

External links

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