Bostryx chusgonensis
Encyclopedia
Bostryx chusgonensis is a species
of tropical air-breathing land snail
, a pulmonate gastropod mollusk in the family Orthalicidae
.
The nominate taxon was described from La Libertad Region
, Río Chusgon area, at 1550-1900 m.
The type locality of Bostryx chusgonensis sipas is Shipasbamba [05°54’25’S 078°02’35’W, 1360 m], Amazonas Region
, Peru. The description of Bostryx chusgonensis sipas extends the range ca. 180 km more northward within the drainage system of the Río Marañon. The Bostryx chusgonensis sipas is separated by mountain ranges from the nominate subspecies.
The height of the shell
is up to 13.4 mm, three times as long as wide, rimate, spindle-shaped, with slightly convex sides, rather thin. Colour is uniformly greyish-whitish or with axial streaks of light to dark-brown, the upper whorls somewhat darker; a dark band around the rimate umbilicus. Surface is hardly shining, with incrassate growth striae. Protoconch
is smooth. The shell has 6.5 whorls
, that are hardly convex. The suture is slightly impressed. The aperture
is elongate-ovate, margins somewhat converging; 1.59 times as long as wide, 0.25 times the total height. Peristome simple, whitish. Columellar margin straight, hardly expanded; no parietal callus.
Dimension of the holotype of Bostryx chusgonensis sipas are as follows: The width of the shell is 4.7 mm. The height of the shell is 13.5 mm. The width of the aperture is 3.2 mm. The height of the aperture is 5.2 mm. The height of the last whorl is 8.39 mm. The shell has 6.5 whorls.
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 tropical air-breathing land snail
Land snail
A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...
, a pulmonate gastropod mollusk 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...
.
Subspecies
- Bostryx chusgonensis chusgonensis Weyrauch, 1960
- Bostryx chusgonensis sipas Breure & Mogollón Avila, 2010
Distribution
The nominate taxon was described from La Libertad Region
La Libertad Region
La Libertad is a region in northwestern Peru. Formerly it was known as the 'Department of La Libertad" , a political division that generally corresponds to a state in the United States of America...
, Río Chusgon area, at 1550-1900 m.
The type locality of Bostryx chusgonensis sipas is Shipasbamba [05°54’25’S 078°02’35’W, 1360 m], Amazonas Region
Amazonas Region
Amazonas is a department of northern Peru bordered by Ecuador on the north and west, Cajamarca Department on the west, La Libertad Department on the south, and Loreto Department and San Martín Department on the east. Its capital is the city of Chachapoyas....
, Peru. The description of Bostryx chusgonensis sipas extends the range ca. 180 km more northward within the drainage system of the Río Marañon. The Bostryx chusgonensis sipas is separated by mountain ranges from the nominate subspecies.
Description
According to Weyrauch (1960) a ribbed form and a colour form with small brownish dots occur in the nominate subspecies.Bostryx chusgonensis sipas
Subspecies Bostryx chusgonensis sipas differs from Bostryx chusgonensis chusgonensis by (1) being larger (up to 13.4 vs. 11.4 mm), (2) the less impressed suture, (3) in streaked specimens, the axial streaks continuing till the base of the shell. The subspecific name sipas is derived from "(Quechua) sipas", that means young woman; referring to the spindle-shaped shell and to the type locality, Shipasbamba. The epithet is used as a noun in apposition. It is characterized by its small size (13 mm), spindle-shape, whitish colour and smooth surface.The height of 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 up to 13.4 mm, three times as long as wide, rimate, spindle-shaped, with slightly convex sides, rather thin. Colour is uniformly greyish-whitish or with axial streaks of light to dark-brown, the upper whorls somewhat darker; a dark band around the rimate umbilicus. Surface is hardly shining, with incrassate growth striae. Protoconch
Protoconch
A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
is smooth. The shell has 6.5 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...
, that are hardly convex. The suture is slightly impressed. 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 elongate-ovate, margins somewhat converging; 1.59 times as long as wide, 0.25 times the total height. Peristome simple, whitish. Columellar margin straight, hardly expanded; no parietal callus.
Dimension of the holotype of Bostryx chusgonensis sipas are as follows: The width of the shell is 4.7 mm. The height of the shell is 13.5 mm. The width of the aperture is 3.2 mm. The height of the aperture is 5.2 mm. The height of the last whorl is 8.39 mm. The shell has 6.5 whorls.