''Harpago chiragra'', common name the Chiragra spider conch, 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 ...

of very large sea snail, a marine gastropod

mollusk 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 species of molluscs are recognized. The number of fossil species is e ...

in the family

Strombidae Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails in the superfamily Stromboidea, and the Epifamily Neostromboidae. The term true conchs, being a common name, does not have an exact me ...

, the true conchs.Bouchet, P. (2011). Harpago chiragra (Linnaeus, 1758). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=564725 on 2011-04-23

Shell description

The shell length for this species varies between 85 mm and 320 mm, usually to 170 mm.Poutiers, J. M. (1998). [ftp://ftp.fao.org/docrep/fao/009/w7191e/w7191e40.pdf Gastropods in: ''FAO Species Identification Guide for Fishery Purposes: The living marine resources of the Western Central Pacific Volume 1.'' Seaweeds, corals, bivalves and gastropods]. Rome, FAO, 1998. page 477. ''Harpago chiragra'' has a very thick, robust and heavy shell, with a distinct anterior notch. Its most prominent characteristic are the six long and curved marginal digitations, expanded from the flaring, thick outer lip and canals. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

and

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

are lirate.

Anatomy

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 an ...

is strongly present in this species. Female individuals are usually much larger than the male ones.

Distribution

''Harpago chiragra'' is widely distributed in the Indo-Pacific, ranging from the Aldabra Atoll,

Chagos The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives arc ...

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 ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

, Sri Lanka and the Gulf of Bengal to eastern

Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...

. It ranges north as far as

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

and southern Japan, and south to New Caledonia and Australia.

Ecology

Habitat

''Harpago chiragra'' lives in

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. C ...

areas. It can be found in

littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal a ...

and

sublittoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal area ...

zones, in tidal pools and low tide levels to a depth of around 25 m.

Feeding habits

''Harpago chiragra'' is known to be an herbivore, feeding on

plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude ...

and algae.

Human uses

The flesh of ''H. chiragra'' is edible, and it is locally collected for food. The shell is used in

shellcraft Shellcraft, also known as shell craft, is the craft of making decorative objects, or of decorating surfaces, using seashells. The craft includes the design and creation of small items such as shell jewelry and figurines made from shells; middle-s ...

References

* Dautzenberg, Ph. (1929). ''Mollusques testacés marins de Madagascar''. Faune des Colonies Francaises, Tome III * Walls, J.G. (1980). ''Conchs, tibias and harps. A survey of the molluscan families Strombidae and Harpidae''. T.F.H. Publications Ltd, Hong Kong

External links

* {{Taxonbar, from=Q1257283 Strombidae Gastropods described in 1758 Taxa named by Carl Linnaeus