Latia neritoides
Encyclopedia
Latia neritoides is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small freshwater snail
Freshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

 or 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...

, an aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 gastropod mollusc 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...

 Latiidae.

The type specimen is in the British Museum
British Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...

.

The specific epithet "neritoides" means "like a nerite". The shell of this species has an internal shelf or lamella, but it more closely resembles a shell of a Crepidula
Crepidula
Crepidula, common name the "slipper limpets" or "slipper shells", is a genus of sea snails, marine gastropod mollusks in the family Calyptraeidae, the slipper snails and cup-and-saucer snails....

than it does a Nerita
Nerita
Nerita is a genus of medium-sized sea snails with a gill and an operculum, marine gastropod molluscs in the family Neritidae, the nerites.This is the type genus of the family Neritidae.-Distribution and habitat:...

.

Shell description

The length of the shell is up to 11 mm. The width of the shell is up to 8 mm. The height of the shell is up to 4.5 mm.

The length of the shell is 8.5 mm. The width of the shell is 6 mm. The height of the shell is 3 mm.

The shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 is semiovate, thin and fragile, almost smooth, brown, semitransparent. Sculpture consisting of microscopic rather distant radiate striae, and fine dense concentric growth-lines. Colour pale to dark brown; interior dark brown in the centre, the lamina white. 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...

 posterior, extending a little beyond the margin, with a spiral nucleus of 1 whorl
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...

, visible on the right side. The apex is generally on the left side, but sometimes near the middle of the posterior margin.

The 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 large, oval, the thin sharp margin generally rounded, but the posterior part of it is occasionally straightened and forming more or
less distinct angles with the lateral sides, which themselves may become almost straight. The inside is polished. The lamella has the left attached end near the middle of the left margin, but the right free end does not extend beyond the posterior third of the length of the shell.

Anatomy

The animal has ringed filiform tentacles. The eyes are situated at the outer bases of the tentacles.

The formula of the radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

 is 30 x 27 + 1 + 27. The central tooth is small and bicuspid. The lateral teeth increasing in size up to the 16th, and then diminish again, they have first 1, then 2, and near the margin 3 cusps.

Bioluminescence

These animals are bioluminescent and highly phosphorescent. This can easily be seen in the dark by disturbing the animals, or by adding a few drops of alcohol to the water. This is the only known freshwater gastropod that emits light.

Latia luciferin
Luciferin
Luciferins are a class of light-emitting biological pigments found in organisms that cause bioluminescence...

 is chemically (E)-2-methyl-4-(2,6,6-trimethyl-1-cyclohex-1-yl)-1-buten-1-ol formate.

The chemical reaction is like this:

Latia luciferin + XH2 + 2 O2 → oxidized Latia luciferin + CO2 + HCOOH
Formic acid
Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...

 + X + H2O + light

XH2 is a reducing agent. Cofactor
Cofactor (biochemistry)
A cofactor is a non-protein chemical compound that is bound to a protein and is required for the protein's biological activity. These proteins are commonly enzymes, and cofactors can be considered "helper molecules" that assist in biochemical transformations....

 is luciferase
Luciferase
Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...

 and a purple protein.

Further reading

  • Hubendick B. (1979) "Figures of Latia neritoides". Journal of Molluscan Studies 45: 353-354. abstract
  • Ohmiya Y., Kojima S., Nakamura M. & Niwa N. (2005) "Bioluminescence in the Limpet-Like Snail, Latia neritoides". Bulletin of the Chemical Society of Japan
    Bulletin of the Chemical Society of Japan
    Founded in 1926, the Bulletin of the Chemical Society of Japan is a scientific journal published by the Chemical Society of Japan. Due to World War II publication was suspended between 1945 to 1946...

    78(7): 1197-1205. abstract, abstract
  • Shimomura O. & Johnson F. H. (May 1968) "The structure of Latia luciferin.". Biochemistry 7(5): 1734-1738.

External links

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