''Dromia dormia'', the sleepy sponge crab or common sponge crab, is the largest

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 ...

of sponge crab. It grows to a

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 of and lives in shallow waters across the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region.

Distribution

''Dromia dormia'' has a widespread distribution in the

region. Its range extends from

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

(including

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

, the

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, V ...

and

Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ...

) and the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

through the

Malay Archipelago The Malay Archipelago (Indonesian/Malay: , tgl, Kapuluang Malay) is the archipelago between mainland Indochina and Australia. It has also been called the " Malay world," "Nusantara", "East Indies", Indo-Australian Archipelago, Spices Archipe ...

, south to

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

(

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

), north to

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

and as far east as

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

and

French Polynesia )Territorial motto: ( en, "Great Tahiti of the Golden Haze") , anthem = , song_type = Regional anthem , song = " Ia Ora 'O Tahiti Nui" , image_map = French Polynesia on the globe (French Polynesia centered).svg , map_alt = Location of Frenc ...

. It is mostly found in shallow waters, with the deepest record being .

Description

''Dromia dormia'' is the largest species in the family

Dromiidae Dromiidae is a family of crabs, often referred to as sponge crabs. They are small or medium-sized crabs which get their name from the ability to shape a living sponge into a portable shelter for themselves.Encarta Reference Library Premium 2005 D ...

, at up to across the

for males, and up to for females.

Behaviour

Like other related crabs, ''D. dormia''

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

s itself by carrying a

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

on its back, which it cuts to size with its claws, and then holds in place with its last two pairs of legs. Instead of a sponge, ''D. dormia'' has occasionally been observed carrying other materials, including a hollow piece of wood, and the sole of a discarded shoe.

Life cycle

Little reproductive data is available for ''D. dormia''. One ovigerous (egg-carrying) female from the

Marquesas Islands The Marquesas Islands (; french: Îles Marquises or ' or '; Marquesan: ' ( North Marquesan) and ' ( South Marquesan), both meaning "the land of men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in th ...

was carrying around 130,000 eggs, each 0.5 mm in diameter.

Taxonomic history

''Dromia dormia'' was among the first dromiid crabs to be collected, because of its large size and the fact that it occurs in shallow waters. It was first described 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 ...

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 ...

'', under the name ''Cancer Dormia''. An earlier description was published by

Georg Eberhard Rumphius Georg Eberhard Rumphius (originally: Rumpf; baptized c. 1 November 1627 – 15 June 1702) was a German-born botanist employed by the Dutch East India Company in what is now eastern Indonesia, and is best known for his work ''Herbarium Amboinense' ...

in his 1705 work '' De Amboinsche Rariteitkamer'', but this predates the starting point for

zoological nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the In ...

. There are a number of related species, which have often been confused with each other, including "''Dromia rumphii''", some examples of which are now considered to belong to '' Lauridromia dehaani''.

References

{{Taxonbar, from=Q3932665 Dromiacea Crustaceans described in 1763 Taxa named by Carl Linnaeus