''Nacella concinna'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a

true limpet The Patellogastropoda, common name true limpets and historically called the Docoglossa, are members of a major phylogenetic group of marine gastropods, treated by experts either as a clade or as a taxonomic order. The clade Patellogastropoda is ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Nacellidae Nacellidae is a taxonomic family of sea snails or true limpets, marine gastropod molluscs in the subclass Patellogastropoda. Taxonomy Nacellidae was the only family in the superfamily Nacelloidea as described by Bouchet & Rocroi (2005),. H ...

, one of the families of true limpets.Bouchet, P. (2014). Nacella polaris (Hombron & Jacquinot, 1841). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=713922 on 2015-01-26

Description

The shell of ''Nacella concinna'' grows to about long with deep water specimens being rather smaller. It is an elongated ovate, moderately elevated cone with a low apex somewhat towards the anterior margin and angled in that direction. There are about 30 faint radial ribs and a series of fine concentric lines that indicate the annual growth rings. The exterior of the shell is varying shades of pale brown and grey and the interior is dark purplish-brown in deep water specimens but creamy-brown in those from shallow water. The mantle has a fringe of short tentacles.''Nacella (Patinigera) polaris'' (Strebel, 1908)
The Smithsonian National Museum of Natural History. Retrieved 2012-02-16.

Distribution

''Nacella concinna'' is found on the seabed of the

Scotia Sea The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and is ...

between

Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South America, South American mainland, across the Strait of Magellan. The archipelago consists of the main is ...

and the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martin in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. ...

. The range includes

South Georgia South Georgia is an island in the Atlantic Ocean, South Atlantic Ocean that is part of the British Overseas Territories, British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. ...

, the

South Orkneys The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula South Shetlands The South Shetland Islands are a group of Antarctic islands located in the Drake Passage with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By ...

Bouvet Island Bouvet Island ( ; ) is an uninhabited subantarctic volcanic island and dependency of Norway. It is a protected nature reserve, and situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic Ridge, it is the world's most extre ...

Seymour Island Seymour Island or Marambio Island, is an island in the chain of 16 major islands around the tip of the Graham Land on the Antarctic Peninsula. Graham Land is the closest part of Antarctica to South America. It lies within the section of the isl ...

Paulet Island Paulet Island is a Circle, circular island about in diameter, lying south-east of Dundee Island, off the north-eastern end of the Antarctic Peninsula. Because of its large penguin colony, it is a popular destination for sightseeing tours. D ...

Wandel Island Booth Island (or Wandel Island; ) is a Y-shaped island, long and rising to in the northeast part of the Wilhelm Archipelago, Antarctica. Location Booth Island is off the east end of the Graham Coast on the west side of the Antarctic Peninsul ...

Anvers Island Anvers Island or Antwerp Island or Antwerpen Island or Isla Amberes is a high, mountainous island long, the largest in the Palmer Archipelago of Antarctica. It was discovered by John Biscoe in 1832 and named in 1898 by the Belgian Antarctic Expe ...

and

Petermann Island Petermann Island () is an island long, lying southwest of Hovgaard Island in the Wilhelm Archipelago, Antarctica. Location Petermann Island is off the Graham Coast of the Antarctic Peninsula. It is in the Wilhelm Archipelago, southwest of ...

. The depth range varies from the inter-tidal zone down to though most specimens come from shallow waters a few metres deep.

Biology

''Nacella concinna'' moves around on rocks and soft substrates feeding on algae and diatoms. Its growth rate is slow and it is said to grow to in 21 years and live as long as 60 years. It is

gonochoristic In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contras ...

, individuals being either male or female, and fertilisation is external. The larval development has been little studied. Spawning takes place in the spring algal bloom period. Mature adults often synchronise their spawning, forming spawning towers or groups of up to 35 individuals which may persist for a week or more. These structures are considered likely to improve fertilisation rates as sperm flows have been observed to cascade down the towers in calm water situations. Even in moving water, sperm concentrations are higher and fertilisation is more likely to occur.

References

* Engl W. (2012) ''Shells of Antarctica.'' Hackenheim: Conchbooks. 402 pp

External links

Strebel, H. (1908). Die Gastropoden. In: Wissenschaftliche Ergebnisse der Schwedischen Südpolar-Expedition 1901–1903 unter Leitung von Dr. Otto Nordenskjöld, Bd 6, Lief. 1: 111 pp., 6 pls. Stockholm

Hedley, C. (1916) Mollusca. Scientific Reports of the Australasian Antarctic Expedition, 1911–1914. Under the Leadership of Sir Douglas Mawson, D. Sc., B. E., Scientific Results Series C.-Zoology and Botany, 4, 1–80, 9 pls.

Hombron J.B. & Jacquinot C.H. (1841). Description de quelques mollusques provenant de la campagne de l'Astrolabe et de la Zélée. Annales des Sciences Naturelles. ser. 2, Zoologie, 16: 62-65, 190-192

González-Wevar C.A., Hüne M., Rosenfeld S., Nakano T., Saucède T., Spencer H. & Poulin E. (2018). Systematic revision of Nacella (Patellogastropoda: Nacellidae) based on a complete phylogeny of the genus, with the description of a new species from the southern tip of South America. Zoological Journal of the Linnean Society. DOI: 10.1093/zoolinnean/zly067

Powell, A. W. B. (1973). The patellid limpets of the world (Patellidae). Indo-Pacific Mollusca. 3(15): 75-206
{{DEFAULTSORT:Nacella Concinna Nacellidae Gastropods described in 1908