Truncatella | |
---|---|
Two live individuals of Truncatella subcylindrica : a juvenile on the left, and an adult on the right | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Caenogastropoda |
Order: | Littorinimorpha |
Family: | Truncatellidae |
Subfamily: | Truncatellinae |
Genus: | Truncatella Risso, 1826 [1] |
Truncatella is a genus of very small land snails with an operculum, terrestrial gastropod mollusks in the family Truncatellidae. These minute snails live in land habitats close to seawater. They walk with a looping action, and the adults have truncated shells. Many of the species are small enough to be considered micromollusks.
Truncatella is the type genus of the family Truncatellidae. [2]
As implied by the name, these snails are notable for the way they modify their elongated shells as they mature, breaking off several of the apical whorls, and forming a relatively smooth seal for the remainder of the shell.
The method of locomotion used by Truncatella is unusual. [4] Instead of gliding over a slime trail using minute waves in its foot, Truncatella uses a very large and muscular proboscis to reach ahead and grasp a surface, at which point the small foot releases its hold and the proboscis contracts to pull the animal forward, after which the entire procedure is usually repeated. [5]
This genus occurs in tropical and subtropical areas. The various species of Truncatella are pantropical in distribution, with a few exceptions such as Truncatella truncatula and Truncatella subcylindrica .
Most of the species in this genus live in a habitat that is neither fully terrestrial nor fully marine: they live under plant debris near high tide level, where they are occasionally wetted with seawater by waves. A small minority of the species are fully terrestrial.
These small snails are typically found associated with drifts of plant material, where their eggs are deposited. [6]
The adaptations of these land snails to the terrestrial environment are not so perfect as they are in the more usual pulmonate land snails, and their terrestrial adaptations may in fact be comparatively recent. [7]
The genus Truncatella was erected by Antoine Risso (Risso, 1826) [1] for T. costulata (now T. subcylindrica), which is the type species for this genus.
There are several genera within the Truncatellidae, but the eponymous genus Truncatella is the largest (in terms of number of species); other genera in the family are Geomelania , Taheitia , and Blandiella. [3] [8] [9]
There are approximately 30 species in the genus Truncatella, including:
Tegula is a genus of small to medium-sized sea snails, marine gastropod molluscs in the family Tegulidae.
Haustrum is a genus of sea snails, marine gastropod mollusks in the subfamily Haustrinae of the family Muricidae, the murex snails or rock snails.
Neritidae, common name the nerites, is a taxonomic family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum. The family Neritidae includes marine genera such as Nerita, marine and freshwater genera such as Neritina, and freshwater and brackish water genera such as Theodoxus.
Trimusculus is a genus of medium-sized air-breathing sea snails or false limpets, marine pulmonate gastropod molluscs in the family Trimusculidae.
Phenatoma is a genus of predatory sea snails, marine gastropod mollusks in the family Borsoniidae.
Truncatella guerinii is a species of very small land snail that lives at the edge of the sea, a gastropod mollusk in the family Truncatellidae.
Hipponicidae, common name hoof shells or hoof snails, is a family of small sea snails, limpet-like marine gastropod molluscs in the superfamily Vanikoroidea.
Truncatella subcylindrica is a species of small land snail that lives at the edge of the sea. It has gills and an operculum and is gastropod mollusk or micromollusk in the family Truncatellidae.
Crepidula, commonly known as the slipper snails, slipper limpets, or slipper shells, is a genus of sea snails, marine gastropod mollusks in the family Calyptraeidae. This family includes the slipper snails (Crepidula), hat snails (Calyptraea), spiny slipper snails (Bostrycapulus), and cup-and-saucer snails (Crucibulum) as well as Crepipatella, Siphopatella, Grandicrepidula, and Maoricrypta.
Bittium is a genus of very small sea snails, marine gastropod molluscs in the family Cerithiidae, the horn snails.
Clithon is a genus of freshwater snails or brackish snails that have an operculum, aquatic gastropod molluscs in the family Neritidae, the nerites.
Patella is a genus of sea snails with gills, typical true limpets, marine gastropod mollusks in the family Patellidae, the true limpets.
Cerithidea is a genus of medium-sized sea snails or mud snails, marine gastropod mollusks in the family Potamididae, the horn snails.
Pyramidella is a genus of minute to medium-sized sea snails, marine gastropod mollusc in the subfamily Pyramidellinae of the family Pyramidellidae, the pyrams and their allies.
Smaragdia is a genus of small sea snails, marine gastropod mollusks in the subfamily Neritinae of the family Neritidae, the nerites.
Zoila is a genus of sea snails, marine gastropod molluscs in the family Cypraeidae, the cowries.
Toledonia is a genus of sea snails, marine gastropod molluscs in the family Cylichnidae.
Amathina is a genus of small sea snails, marine heterobranch gastropod molluscs or micromolluscs in the family Amathinidae.
Crenella is a genus of bean mussels in the family Mytilidae.
Cyclostoma is an obsolete genus name of operculate snails with circular aperture.