''Bostryx chusgonensis'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

air-breathing

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

, a

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the family

Bulimulidae Bulimulidae is a taxonomic family of medium-sized to large, air-breathing, tropical and sub-tropical land snails, terrestrial pulmonate gastropod molluscs in the superfamily Orthalicoidea.MolluscaBase eds. (2020). MolluscaBase. Bulimulidae Tryon, ...

Subspecies

* ''Bostryx chusgonensis chusgonensis'' Weyrauch, 1960 * ''Bostryx chusgonensis sipas'' Breure & Mogollón Avila, 2010

Distribution

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

Breure A. S. H. & Mogollón Avila V. (2010). "Well-known and little-known: miscellaneous notes on Peruvian Orthalicidae (Gastropoda, Stylommatophora)". ''

Zoologische Mededelingen ''Zoologische Mededelingen'' was a peer-reviewed open access scientific journal publishing papers and monographs on animal systematics. The publisher was the National Museum of Natural History Naturalis in the Netherlands. The first issue appeared ...

'' 84
HTM
. The nominate taxon was described from

La Libertad Region La Libertad (; in English: ''The Liberty'') is a region in northwestern Peru. Formerly it was known as the Department of La Libertad ('). It is bordered by the Lambayeque, Cajamarca and Amazonas regions on the north, the San Martín Region on t ...

, Río Chusgon area, at 1550–1900 m. The type locality of ''Bostryx chusgonensis sipas'' is

Shipasbamba Shipasbamba is a district in Bongará Province, Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal ( ...

5°54’25’S 078°02’35’W, 1360 m

Amazonas Region Amazonas () is a department and region in northern Peru bordered by Ecuador on the north and west, Cajamarca on the west, La Libertad on the south, and Loreto and San Martín on the east. Its capital is the city of Chachapoyas. With a lands ...

, 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,

. 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 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 A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

is smooth. The shell has 6.5

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

, that are hardly convex. The suture is slightly impressed. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

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.

References

This article incorporates CC-BY-3.0 text from the reference {{Taxonbar, from=Q4948306 Bulimulidae Gastropods described in 1960