Sand bubbler crabs (or sand-bubblers) are

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 ...

s of the

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

''Scopimera'' and ''Dotilla'' in the family Dotillidae. They are small crabs that live on sandy beaches in the tropical

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 ...

. They feed by filtering sand through their mouthparts, leaving behind balls of sand that are broken up by the incoming high tide.

Description

Sand bubbler crabs are small crabs, around across the

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 ...

, and they are characterised by the presence of "gas windows" on the merus of the

legs A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...

; in ''Dotilla'', these windows are also present on the

thoracic The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main ...

sternite The sternum (: sterna) is the ventral portion of a segment of an arthropod thorax or abdomen. In insects, the sterna are usually single, large sclerites, and external. However, they can sometimes be divided in two or more, in which case the su ...

s. A similar system has evolved in parallel in the

porcelain crab Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attacke ...

genus '' Petrolisthes''.

Distribution

Sand bubbler crabs are widespread across the

region, where they occur abundantly on sandy beaches in the tropics and sub-tropics.

Ecology and behaviour

Sand bubbler crabs live in

burrow file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...

s in the sand, where they remain during high tide. When the tide is out, they emerge on to the surface of the sand, and pass the sand through their mouthparts, eating detritus and plankton, and discarding the processed sand as pellets, which cover the beach. The crabs work radially from the entrance to their burrows, which they re-enter as the tide rises and disintegrates the pellets. In each burrow, the crab waits out the high tide in a bubble of air. The material consumed by sand bubbler crabs has a very low concentration of organic matter, which is concentrated by egestion of indigestible material.

Taxonomy

Taxonomic history

The first sand bubbler crab to be described was ''Cancer sulcatus'' (now '' Dotilla sulcata'') by

Peter Forsskål Peter Forsskål, sometimes spelled Pehr Forsskål, Peter Forskaol, Petrus Forskål or Pehr Forsskåhl (11 January 1732 – 11 July 1763) was a Sweden, Swedish exploration, explorer, oriental studies, orientalist, natural history, naturalist, and ...

in 1775. The genus ''Scopimera'' was originally described as a

subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...

of ''

Ocypode ''Ocypode'' is a genus of ghost crabs found in the sandy shores of tropical and subtropical regions throughout the world. They have a box-like body, thick and elongated eyestalks, and one claw is larger than the other in both males and females ...

'' by

Wilhem de Haan Wilhem de Haan (7 February 1801 in Amsterdam – 15 April 1855 in Leiden) was a Dutch zoologist. He specialised in the study of insects and crustaceans, including aquatic arthropods, and was the first keeper of invertebrates at the Rijksmuseum i ...

in 1833, although the first species, ''Scopimera globosa'' was not validly described until 1835. At the same time, De Haan tried to erect the genus ''Doto'' for Forskål's ''Cancer sulcatus'', not realising that the name was

preoccupied In biology, a homonym is a name for a taxon that is identical in spelling to another such name, that belongs to a different taxon. The rule in the International Code of Zoological Nomenclature is that the first such name to be published is the s ...

by the

mollusc 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 ...

genus '' Doto''. The first available name for that genus was published by

William Stimpson William Stimpson (February 14, 1832 – May 26, 1872) was an American scientist. He was interested particularly in marine biology. Stimpson became an important early contributor to the work of the Smithsonian Institution and later, director o ...

in 1858, who called it ''Dotilla''. Ongoing

revisions ''ReVisions'' is a 2004 anthology of alternate history Alternate history (also referred to as alternative history, allohistory, althist, or simply A.H.) is a subgenre of speculative fiction in which one or more historical events have occurred ...

are likely to split the current genus ''Scopimera'' into at least two genera.

Species

Eight species of ''Dotilla'' and fifteen of ''Scopimera'' are currently recognised: * ''Dotilla'' ** '' Dotilla blanfordi'' Alcock, 1900 ** '' Dotilla fenestrata'' Hilgendorf, 1869 ** '' Dotilla intermedia'' De Man, 1888 ** '' Dotilla malabarica'' Nobili, 1903 ** ''

Dotilla myctiroides ''Dotilla myctiroides'' is a species of sand bubbler crab found on tropical shores and mud-flats of India, Thailand, Malaysia, Indonesia, Singapore and Sri Lanka. They breed throughout the year but activity peaks during the monsoons. This species ...

'' (H. Milne-Edwards, 1852) ** '' Dotilla pertinax'' Kemp, 1915 ** '' Dotilla sulcata'' (Forskål, 1775) ** '' Dotilla wichmanni'' De Man, 1892 * ''Scopimera'' ** '' Scopimera bitympana'' Shen, 1930 ** '' Scopimera crabicauda'' Alcock, 1900 ** '' Scopimera curtelsoma'' Shen, 1936 ** '' Scopimera globosa'' (De Haan, 1835) ** '' Scopimera gordonae'' Serène & Moosa, 1981 ** '' Scopimera inflata'' A. Milne-Edwards, 1873 ** '' Scopimera intermedia'' Balss, 1934 ** '' Scopimera investigatoris'' Alcock, 1900 ** '' Scopimera kochi'' Roux, 1917 ** '' Scopimera longidactyla'' Shen, 1932 ** '' Scopimera philippinensis'' Wong, Shih & Chan, 2011 ** '' Scopimera pilula'' Kemp, 1919 ** '' Scopimera proxima'' Kemp, 1919 ** '' Scopimera sheni'' Wong, Shih & Chan, 2011 ** '' Scopimera sigillorum'' (Rathbun, 1914)

References

External links

* {{Taxonbar, from=Q1227769 Ocypodoidea Arthropod common names