Lacuna (gastropod)
Encyclopedia
Lacuna is a genus
of sea snail
s, marine
gastropod mollusks in the family
Littorinidae
, the winkles or periwinkles.
with two thick lips and a spiral, filiform tongue. There are two slender, contractile tentacles with the eyes on small pedicels near their base. The foot is oval and somewhat broader behind.
The thin shell has an ovate-conical or subglobose shape and is covered with a delicate horny periostracum
. It has a short spire with convex whorls
that are rapidly expanding. The last whorl is ventricose, i.e. inflated in the middle. The apex
is rather obtuse. The oval or roundish aperture
is covered with a horny, spirally marked operculum
. The peristome
is incomplete behind. The columella is flattened and forms with the peristome an elongated groove continued from the umbilicus. This groove is bounded internally by the decurved margin of the pillar.
Species brought into synonymy :
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 sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
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 mollusks 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...
Littorinidae
Littorinidae
Littorinidae is a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found world-wide.-Names:...
, the winkles or periwinkles.
Description
The spiral animal body is elongated. The mouth has a proboscisProboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
with two thick lips and a spiral, filiform tongue. There are two slender, contractile tentacles with the eyes on small pedicels near their base. The foot is oval and somewhat broader behind.
The thin shell has an ovate-conical or subglobose shape and is covered with a delicate horny periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
. It has a short spire with convex whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
that are rapidly expanding. The last whorl is ventricose, i.e. inflated in the middle. The 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...
is rather obtuse. The oval or roundish aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is covered with a horny, spirally marked operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
. The peristome
Peristome
The word peristome is derived from the Greek peri, meaning 'around' or 'about', and stoma, 'mouth'. It is a term used to describe various anatomical features that surround an opening to an organ or structure. The term is used in plants and invertebrate animals, such as in describing the shells of...
is incomplete behind. The columella is flattened and forms with the peristome an elongated groove continued from the umbilicus. This groove is bounded internally by the decurved margin of the pillar.
Species
Species within the genus Lacuna include:- Lacuna abyssicolaLacuna abyssicolaLacuna abyssicola is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.This name is a nomen nudum...
Melvill & Standen, 1912 : nomen nudum - Lacuna cariniferaLacuna cariniferaLacuna carinifera is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
A. Adams, 1851 - Lacuna cleicecabrale Barros, 1994
- Lacuna crassiorLacuna crassiorLacuna crassior is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.-Distribution:Lacuna crassior is a circumboreal and subarctic species that has Britain as its southern limit...
(Montagu, 1803) - Lacuna decotataLacuna decotataLacuna decorata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.-References:...
A. Adams, 1861 - Lacuna latifasciataLacuna latifasciataLacuna latifasciata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
A. Adams, 1863 - Lacuna lepidulaLacuna lepidulaLacuna lepidula is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
A. Adams, 1863 - Lacuna lukiniiLacuna lukiniiLacuna lukinii is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Golikov & Gulbin, 1985) - Lacuna marmorataLacuna marmorataLacuna marmorata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Dall, 1919 - Lacuna minorLacuna minorLacuna minor is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Dall, 1919) - Lacuna orientalisLacuna orientalisLacuna orientalis is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Golikov & Gulbin, 1985) - Lacuna pallidulaLacuna pallidulaLacuna pallidula, common name the pale lacuna, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(da Costa, 1778) - Lacuna parvaLacuna parvaLacuna parva, common name the tiny lacuna, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(da Costa, 1778) - Lacuna pumilio E. A. Smith, 1890
- Lacuna porrectaLacuna porrectaLacuna porrecta is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Carpenter, 1864 - Lacuna reflexaLacuna reflexaLacuna reflexa is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Dall, 1884) - Lacuna setonaikaiensisLacuna setonaikaiensisLacuna setonaikaiensis is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Habe, 1958) - Lacuna smithiiLacuna smithiiLacuna smithii is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Pilsbry, 1895 - Lacuna succineaLacuna succineaLacuna succinea is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Berry, 1953 - Lacuna turneriLacuna turneriLacuna turneri is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Dall, 1886) - Lacuna turritaLacuna turritaLacuna turrita is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
A. Adams, 1861 - Lacuna uchidaiLacuna uchidaiLacuna uchidai is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Habe, 1953) - Lacuna unifasciataLacuna unifasciataLacuna unifasciata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Carpenter, 1856 - Lacuna variegataLacuna variegataLacuna variegata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
Carpenter, 1864 - Lacuna vinctaLacuna vinctaLacuna vincta, common name the northern lacuna, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles....
(Montagu, 1803)
Species brought into synonymy :
- Lacuna cossmanni Locard, 1897 : synonym of Benthobia tryoniiBenthobia tryoniiBenthobia tryonii is a species of sea snail, a marine gastropod mollusk in the family Pseudolividae....
Dall, 1889 - Lacuna macmurdensis Hedley, 1911 : synonym of Trilirata macmurdensis (Hedley, 1911)
- Lacuna mediterranea Monterosato, 1869 : synonym of Ersilia mediterranea (Monterosato, 1869)
- Lacuna neritoidea Gould, 1840 : synonym of Lacuna pallidula (da Costa, 1778)
- Lacuna notorcadensis Melvill & Standen, 1907 : synonym of Laevilitorina wandelensisLaevilitorina wandelensisLaevilitorina wandelensis is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.-References:...
(Lamy, 1905) - Lacuna patula Thorpe, 1844 : synonym of Lacuna pallidula (da Costa, 1778)
- Lacuna puteolus (Turton, 1819) : synonym of Lacuna parva (da Costa, 1778)