Dromia dormia
Encyclopedia
Dromia dormia, the sleepy sponge crab or common sponge crab, is the largest species
of sponge crab
. It grows to a carapace
width of 20 cm (8 in) and lives in shallow waters across the Indo-Pacific
region.
region. Its range extends from East Africa
(including Madagascar
, the Seychelles
and Mauritius
) and the Red Sea
through the Malay Archipelago
, south to Queensland
(Australia
), north to China
and Japan
and as far east as Hawaii
and French Polynesia
. It is mostly found in shallow waters, with the deepest record being 112 m (367.5 ft).
, at up to 200 millimetres (7.9 in) across the carapace
for males, and up to 172 mm (6.8 in) for females.
s itself by carrying a sponge 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.
was carrying around 130,000 eggs, each 0.5 mm in diameter.
by Carl Linnaeus in his 1763 work Centuria Insectorum
, under the name Cancer Dormia. An earlier description was published by Georg Eberhard Rumphius
in his 1705 work De Amboinsche Rariteitkamer, but this predates the starting point for zoological nomenclature. 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.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sponge crab
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. A sponge crab cuts out a fragment from a sponge and trims it to its own shape using its claws...
. It grows to a carapace
Carapace
A carapace is a dorsal 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 underside is called the plastron.-Crustaceans:In crustaceans, the...
width of 20 cm (8 in) and lives in shallow waters across the Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region.
Distribution
Dromia dormia has a widespread distribution in the Indo-PacificIndo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region. Its range extends from East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
(including Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
and Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
) and the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
through the Malay Archipelago
Malay Archipelago
The Malay Archipelago refers to the archipelago between mainland Southeastern Asia and Australia. The name was derived from the anachronistic concept of a Malay race....
, south to Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
(Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
), north to China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and as far east as Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and French Polynesia
French Polynesia
French Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
. It is mostly found in shallow waters, with the deepest record being 112 m (367.5 ft).
Description
Dromia dormia is the largest species in the family DromiidaeDromiidae
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. A sponge crab cuts out a fragment from a sponge and trims it to its own shape using its claws...
, at up to 200 millimetres (7.9 in) across the carapace
Carapace
A carapace is a dorsal 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 underside is called the plastron.-Crustaceans:In crustaceans, the...
for males, and up to 172 mm (6.8 in) for females.
Behaviour
Like other related crabs, D. dormia camouflageCamouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
s itself by carrying a sponge 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 IslandsMarquesas Islands
The Marquesas Islands enana and Te Fenua `Enata , both meaning "The Land of Men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. The Marquesas are located at 9° 00S, 139° 30W...
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 describedAlpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...
by Carl Linnaeus in his 1763 work Centuria Insectorum
Centuria Insectorum
is a 1763 taxonomic work by Carl Linnaeus, and defended as a thesis by Boas Johansson; which of the two men should be credited with its authorship has been the subject of some controversy. It includes descriptions of 102 new insect and crustacean species that had been sent to Linnaeus from...
, under the name Cancer Dormia. An earlier description was published by Georg Eberhard Rumphius
Georg Eberhard Rumphius
Georg Eberhard Rumphius or originally Rumpf 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. 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.