Emarginula is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of small keyhole limpet

Limpet

Limpet is a common name for a number of different kinds of saltwater and freshwater snails ; it is applied to those snails that have a simple shell which is more or less conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snails.The name limpet is most...

s, marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod molluscs in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Fissurellidae.

Description

The oval shell is obliquely conical with a backward-pointing recurved apex

Apex (mollusc)

Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...

. There is a deep incision in the anterior margin. A distinct anal fasciole extends upwards from this incision. The surface is latticed, sculptured with radial ribs. There is no septum

Septum

In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...

 inside.

Radula

The radula has a dental formula of [many].1.4.1.4.1.[many], with a wide, rectangular, acuspate rachidian tooth.
The various genera have a few dozen rows of teeth.

Species

According to the World Register of Marine Species

World Register of Marine Species

The World Register of Marine Species is a database that hopes to provide an authoritative and comprehensive list of names of marine organisms. The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the...

 (WoRMS), species within the genus Emarginula include:

• Emarginula adriatica
  Emarginula adriatica
  Emarginula adriatica is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Costa O.G., 1829
• Emarginula arabica
  Emarginula arabica
  Emarginula arabica is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  A. Adams, 1851
• Emarginula arconatii
  Emarginula arconatii
  Emarginula arconatii is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Issel, 1869
• Emarginula bonfittoi
  Emarginula bonfittoi
  Emarginula bonfittoi is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Smriglio & Mariottini, 2001
• Emarginula christiaensi
  Emarginula christiaensi
  Emarginula christiaensi is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Piani, 1985
• Emarginula costulata
  Emarginula costulata
  Emarginula costulata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Deshayes, 1863
• Emarginula crassa
  Emarginula crassa
  Emarginula crassa, the thick slit limpet, is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets.-Description:...
  
  Sowerby, 1812
• Emarginula cuvieri
  Emarginula cuvieri
  Emarginula cuvieri is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Audouin, 1827
• Emarginula decorata
  Emarginula decorata
  Emarginula decorata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Deshayes, 1863
• Emarginula dentigera
  Emarginula dentigera
  Emarginula dentigera is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Heilprin, 1889 - toothed emarginula
• Emarginula divae
  Emarginula divae
  Emarginula divae is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  (van Aartsen & Carrozza, 1995)
• Emarginula fissura
  Emarginula fissura
  Emarginula fissura , the common slit limpet, is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  (Linnaeus, 1758) - slit limpet
• Emarginula foveolata
  Emarginula foveolata
  Emarginula foveolata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  
  • Emarginula foveolata fugitai Habe, 1953
• Emarginula gigantea
  Emarginula gigantea
  Emarginula gigantea is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Poppe, 2008
• Emarginula huzardii
  Emarginula huzardii
  Emarginula huzardii is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets.-Description:...
  
  (Payraudeau, 1826)
• Emarginula multistriata
  Emarginula multistriata
  Emarginula multistriata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Jeffreys, 1882
• Emarginula nordica
  Emarginula nordica
  Emarginula nordica, common name the northern emarginula, is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Pérez Farfante, 1947 - northern emarginula
• Emarginula octaviana
  Emarginula octaviana
  Emarginula octaviana is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Coen, 1939
• Emarginula paivana
  Emarginula paivana
  Emarginula paivana is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  (Crosse, 1867)
• Emarginula papillosa
  Emarginula papillosa
  Emarginula papillosa is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Risso 1826
• Emarginula peasei
  Emarginula peasei
  Emarginula peasei is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Thiele, 1915
• Emarginula phrixodes
  Emarginula phrixodes
  Emarginula phrixodes is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Dall, 1927 - ruffled emarginula
• Emarginula pumila
  Emarginula pumila
  Emarginula pumila, the pygmy ermarginula, is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets.-Description:...
  
  (A. Adams
  Arthur Adams (zoologist)
  Arthur Adams was an English physician and naturalist.Adams was assistant surgeon on board H.M.S. "Actaeon" in company with HMS Samarang in the British Navy during the survey of the Malay Archipelago, the Japan Sea, Korea and China,from 1843 to 1846. He edited the Zoology of the voyage of H.M.S....
  
  , 1852) - pygmy emarginula
• Emarginula punctulum
  Emarginula punctulum
  Emarginula punctulum is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Piani, 1980
• Emarginula pustula
  Emarginula pustula
  Emarginula pustula is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Thiele in Küster, 1913
• Emarginula retecosa
  Emarginula retecosa
  Emarginula retecosa is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  A. Adams, 1851
• Emarginula rosea
  Emarginula rosea
  Emarginula rosea is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Bell , 1824
• Emarginula rugosa
  Emarginula rugosa
  Emarginula rugosa is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Quoy & Gailard, 1834
• Emarginula sicula
  Emarginula sicula
  Emarginula sicula is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  J. E. Gray, 1825 - dagger emarginula
• Emarginula solidula
  Emarginula solidula
  Emarginula solidula is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets.-Distribution:...
  
  Costa, 1829
• Emarginula spinosa
  Emarginula spinosa
  Emarginula spinosa is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Deshayes, 1863
• Emarginula tenera
  Emarginula tenera
  Emarginula tenera is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Locard, 1892
• Emarginula tenuicostata
  Emarginula tenuicostata
  Emarginula tenuicostata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  G.B. Sowerby II, 1863
• Emarginula thomasi
  Emarginula thomasi
  Emarginula thomasi is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Crosse, 1864
• Emarginula tuberculosa
  Emarginula tuberculosa
  Emarginula tuberculosa is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  Libassi, 1859 - tuberculate emarginula
• Emarginula variegata
  Emarginula variegata
  Emarginula variegata is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets....
  
  A. Adams, 1852
• Emarginula velascoensis Shasky, 1961

The following species is mentioned in other databases :

• Emarginula striatula
  Emarginula striatula
  Emarginula striatula is a species of slit limpet, a marine gastropod mollusc in the family Fissurellidae, the keyhole limpets and slit limpets.-Distribution:This species is found only in the vicinity of New Zealand and surrounding islands....
  
  Quoy
  Jean René Constant Quoy
  Jean René Constant Quoy was a French zoologist.Along with Joseph Paul Gaimard he served as naturalist aboard La Coquille under Louis Isidore Duperrey during its circumnavigation of the globe , and the Astrolabe under the command of Jules Dumont d'Urville...
  
   and Gaimard
  Joseph Paul Gaimard
  Joseph Paul Gaimard was a French naval surgeon and naturalist.Along with Jean René Constant Quoy he served as naturalist on the ships L'Uranie under Louis de Freycinet 1817-1820, and L'Astrolabe under Jules Dumont d'Urville 1826-1829...
  
  , 1834 - dagger emarginula

The Indo-Pacific Molluscan Database also mentions the following species with names in current use :

• Emarginula adamsiana Sowerby II in Adams & Sowerby II, 1863
• Emarginula amyda Shikama, 1962
• Emarginula choristes Dall, 1925
• Emarginula compta Habe, 1953
• Emarginula concinna A. Adams, 1852
• Emarginula crassicostata Sowerby II in Adams & Sowerby II, 1863
• Emarginula curvata Schepman, 1908
• Emarginula dilecta A. Adams, 1852
• Emarginula dubia Schepman, 1908
• Emarginula fenestrella Deshayes, 1863
• Emarginula fragilis Yokoyama, 1920
• Emarginula fulginea A. Adams, 1851
• Emarginula hataii Habe, 1953
• Emarginula hosoyai Habe, 1953
• Emarginula imaizumi Dall, 1926
• Emarginula japonica Sowerby II in Adams & Sowerby II, 1863
• Emarginula kashimaensis Shikama, 1962
• Emarginula maculata A. Adams in A. Adams & Sowerby II, 1863
• Emarginula multisquamosa Schepman, 1908
• Emarginula paucipunctata Schepman, 1908
• Emarginula punctata A. Adams, 1852
• Emarginula regia Habe, 1953
• Emarginula sublaevis Schepman, 1908
• Emarginula teramachii Habe, 1953
• Emarginula textilis Gould, 1859 in 1859-61
• Emarginula tosaensis Habe, 1953

Subgenus Emarginula Lamarck, 1801

• Emarginula agulhasensis Thiele, 1925
• Emarginula bellula A. Adams, 1851
• Emarginula bicancellata Montrouzier, 1860
• Emarginula camilla Melvill & Standen, 1903
• Emarginula candida A. Adams, 1852
• Emarginula clathrata Pease, 1862
• Emarginula clypea A. Adams, 1852
• Emarginula connelli Kilburn, 1978
• Emarginula convexa Hedley, 1907
• Emarginula cucullata Adams, 1851
• Emarginula curvamen Iredale, 1925
• Emarginula eximia A. Adams, 1852
• Emarginula fissurata A. Adams, 1851
• Emarginula gabensis (Gabriel, 1961)
• Emarginula harmilensis Sturany, 1903
• Emarginula hawaiiensis Dall, 1895
• Emarginula koon Kilburn, 1978
• Emarginula macclurgi Kilburn, 1978
• Emarginula micans A. Adams, 1852
• Emarginula natalensis Barnard, 1963
• Emarginula nigromaculata (Thiele, 1930)
• Emarginula obovata A. Adams, 1852
• Emarginula oppressa (Barnard, 1963)
• Emarginula patula Cotton, 1930
• Emarginula phrygium Herbert & Kilburn, 1985
• Emarginula plana Schepman, 1908
• Emarginula puncticulata Adams, 1852
• Emarginula scabricostata A. Adams, 1851
• Emarginula scabriuscula A. Adams, 1852
• Emarginula scutellata Deshayes, 1863
• Emarginula subtilitexta Verco, 1908
• Emarginula superba Hedley, 1906
• Emarginula thorektes Kilburn, 1978
• Emarginula undulata Melvill & Standen, 1903
• Emarginula velascoi Rehder, 1980
• Emarginula viridicana Herbert & Kilburn, 1985

Subgenus Subzeidora Iredale, 1924

• Emarginula connectens Thiele, 1915
• Emarginula devota Thiele, 1915
• Emarginula souverbiana Pilsbry, 1890