''Iothia emarginuloides'' 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 ...

Lepetidae Lepetidae is a family (biology), family of sea snails or small, deep-water true limpets, marine (ocean), marine gastropod molluscs in the clade Patellogastropoda the true limpets. Taxonomy This family consists of the two following subfamilies ...

, one of the families of true limpets. This species was previously known as ''Iothia coppingeri''.

Taxonomy

The type specimens of ''I. emarginuloides'' (Philippi, 1868) and ''I. coppingeri'' (E.A. Smith, 1881) are very similar in

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

, and were collected only apart; as long ago as 1908 this led to the recognition that they were probably the same species. Despite this, they continued to be treated as two separate species until 2011, when Nakano et al. researched the genus and brought them into

synonymy A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

. ''I. emarginuloides'' was described before ''I. coppingeri'', so by the rules of zoological nomenclature, the earlier name took priority.

Description

''I. emarginuloides'' is a small, broadly ovate, cap-shaped limpet, with a length of about and width of . The apex of the shell is towards the anterior end, and is rather acute, but does not curl over. The shell is thin, and has fine sculptured lines radiating from the apex which formed the basis for the species' descriptive name, ''emarginuloides'', "as if minutely emarginate, or finely notched". There are also irregular, concentric growth rings. The margin is smooth apart from the fine crenelations produced by the radial sculpture. The shell is a "dirty white" colour, with a few greyish concentric bands. Although limpets in the family

are commonly known as "blind limpets", both this species and the closely related '' Iothia fulva'' have small, black-pigmented eyes, situated close to the base of the tentacles.

Distribution

''I. emarginuloides'' is known from Antarctica (the

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha C ...

) and southern Chile. Its distribution is probably circum-Antarctic, with its known range extending from the

Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the subantarctic, sub-Antarctic region. They are among the Extremes on Earth#Remoteness, most i ...

to the

Strait of Magellan The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and the Tierra del Fuego archipelago to the south. Considered the most important natura ...

area. All records are from water shallower than . It is the commonest animal found living on the red alga '' Phyllophora antarctica'' under the

sea ice Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ...

in the vicinity of the

Vestfold Hills The Vestfold Hills are rounded, rocky, coastal hills, in extent, on the north side of Sorsdal Glacier on the Ingrid Christensen Coast of Princess Elizabeth Land, Antarctica. The hills are subdivided by three west-trending peninsulas bounded by n ...

, Antarctica.

References

* Linse K. (2002). The shelled Magellanic Mollusca: with special reference to biogeography relations in the Southern Ocean. Theses Zoologicae. 34: 1–252 * Warén A., Nakano T. & Sellanes J. (2011) A new species of Iothia (Gastropoda: Lepetidae) from Chilean methane seeps, with comments on the accompanying gastropod fauna. The Nautilus 125(1): 1-14 * Engl, W. (2012). Shells of Antarctica. Hackenheim: Conchbooks. 402 pp. * Güller M. & Zelaya D.G. (2016). Species of Iothia (Gastropoda: Lepetidae) from shallow waters of the Magellan Region. Malacologia. 59(2): 321–330. {{Taxonbar, from=Q13367694 Lepetidae Gastropods described in 1868 Taxa named by Rodolfo Amando Philippi