Anostoma octodentatum
Encyclopedia
Anostoma octodentatum, common name Brazilian up-mouth snail, is a species
of air-breathing land snail
, a terrestrial
pulmonate gastropod mollusk in the subfamily Bulimulinae, in the family Orthalicidae
.
Anostoma octodentatum is the type species
of the genus Anostoma
. The type locality is tropical South America, east of the Andes.
and Amapá
, where it is found uncommonly, living on the ground.
of this species is biconvex. The height of the shell is half or nearly half of the greatest diameter. The shell is solid, and obtusely angular at the periphery.
The shell color is a brown-tinted whitish; the base is copiously dappled with oblong spots, and more or less spirally clouded with dull reddish-brown. The upper surface has a broad reddish-brown band above the periphery. This band is often mottled, and fades out at its upper edge. There is a narrow dark spiral band bordering the suture below, fading on the two earlier whorls. The surface is slightly striate above, and on the first half of the base. The last half whorl is regularly latticed or malleate in a diamond pattern.
The shell has 5 whorls
; the first one is flattened. The last half-whorl is straightened out: it runs to the periphery and is then upturned. It has three long and one short groove behind the lip.
The aperture
of the shell is subhorizontal, rounded, and obstructed by eight folds. The peristome is white, very broadly expanded, reflexed and recurved, rather thick, and arcuate throughout. The parietal callus
is translucent-white, and spreads broadly upon the last and preceding whorls. The parietal margin bears three lamellae: a small, triangular angle-lamella, a large, erect parietal lamella, the inner end of which curves behind the preceding tooth, and a smaller, straight infraparietal lamella near the middle of the parietal margin. The outer lip bears five folds: subequal, straight and rather large upper and lower palatal folds within the outer margin, a somewhat smaller columellar lamella below them,
and two still smaller suprapalatal folds on the upper margin, the upper one of which is smaller and tuberculiform.
The width of the adult shell varies from 39 to 45 mm, the height from 20-21 mm.
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 air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
, a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
pulmonate gastropod mollusk in the subfamily Bulimulinae, in the family Orthalicidae
Orthalicidae
Orthalicidae are a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks are classified in the informal group Sigmurethra of the clade Stylommatophora...
.
Anostoma octodentatum is the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus Anostoma
Anostoma
Anostoma, common name the up-mouth snails, is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the subfamily Bulimulinae, in the family Orthalicidae...
. The type locality is tropical South America, east of the Andes.
Subspecies
- Anostoma octodentatum verreauxianum Hupé, 1857 (photo)
Distribution and habitat
This species occurs in Brazil in the states of CearáCeará
Ceará is one of the 27 states of Brazil, located in the northeastern part of the country, on the Atlantic coast. It is currently the 8th largest Brazilian State by population and the 17th by area. It is also one of the main touristic destinations in Brazil. The state capital is the city of...
and Amapá
Amapá
Amapá is one of the states of Brazil, located in the extreme north, bordering French Guiana and Suriname to the north. To the east is the Atlantic Ocean, and to the south and west is the Brazilian state of Pará. Perhaps one of the main features of the state is the River Oiapoque, as it was once...
, where it is found uncommonly, living on the ground.
Shell description
The shellGastropod 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...
of this species is biconvex. The height of the shell is half or nearly half of the greatest diameter. The shell is solid, and obtusely angular at the periphery.
The shell color is a brown-tinted whitish; the base is copiously dappled with oblong spots, and more or less spirally clouded with dull reddish-brown. The upper surface has a broad reddish-brown band above the periphery. This band is often mottled, and fades out at its upper edge. There is a narrow dark spiral band bordering the suture below, fading on the two earlier whorls. The surface is slightly striate above, and on the first half of the base. The last half whorl is regularly latticed or malleate in a diamond pattern.
The shell has 5 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...
; the first one is flattened. The last half-whorl is straightened out: it runs to the periphery and is then upturned. It has three long and one short groove behind the lip.
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....
of the shell is subhorizontal, rounded, and obstructed by eight folds. The peristome is white, very broadly expanded, reflexed and recurved, rather thick, and arcuate throughout. The parietal callus
Parietal callus
A parietal callus is a feature of the shell anatomy of some groups of snails, i.e. gastropods. It is a thickened calcareous deposit which may be present on the parietal wall of the aperture of the adult shell. The parietal wall is the margin of the aperture and part of the wall of the body whorl...
is translucent-white, and spreads broadly upon the last and preceding whorls. The parietal margin bears three lamellae: a small, triangular angle-lamella, a large, erect parietal lamella, the inner end of which curves behind the preceding tooth, and a smaller, straight infraparietal lamella near the middle of the parietal margin. The outer lip bears five folds: subequal, straight and rather large upper and lower palatal folds within the outer margin, a somewhat smaller columellar lamella below them,
and two still smaller suprapalatal folds on the upper margin, the upper one of which is smaller and tuberculiform.
The width of the adult shell varies from 39 to 45 mm, the height from 20-21 mm.
