Pila occidentalis

Pila occidentalis
Conservation status
Least Concern  (IUCN 3.1) [1]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Architaenioglossa
Family:	Ampullariidae
Genus:	Pila
Species:	P. occidentalis
Binomial name
Pila occidentalis (Mousson, 1887)
Synonyms [1]
Ampullaria occidentalisMousson, 1887

Pila occidentalis is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the apple snails family, Ampullariidae. ^[2]

Description

The length of the shell attains 47 mm, its diameter 48 mm.

(Original description in Latin) The shell is umbilicate, globose, and rather solid. It is irregularly striated but not decussate, appearing brownish-yellow, and is often obscurely marked with broad, frequently geminate (paired) spiral bands. The spire is briefly conical, with a corroded summit; the suture is somewhat impressed and linear.

The shell comprises 5 to 5.5 convex whorls. These are flattened at the suture. The body whorl is not ascending, but is rounded, shouldered above, and more convex towards the umbilicus. The aperture is oval and vertical (at 5° with the axis), nearly equalling four-fifths of the shell's height.It shows translucent bands internally. The peristome is acute and briefly everted; its margins are barely approximated and are joined by a thin lamina. The right margin is excised at nearly a right angle and well incurved, while the basal margin is minimally effuse, passing curvaceously into the gently reflected columellar margin. The operculum is rough and somewhat testaceous. ^[3]

Distribution

This species is found in Angola, Botswana, Namibia, and Zambia. ^[1]

References

1. Kristensen, T.K.; Stensgaard, A-S.; Curtis, B. (2010). "Pila occidentalis". IUCN Red List of Threatened Species . 2010 e.T17278A6916407. doi: 10.2305/IUCN.UK.2010-3.RLTS.T17278A6916407.en . Retrieved 17 November 2021.
2. Pila occidentalis (Mousson, 1888) . 3 June 2025. Retrieved through: World Register of Marine Species .
3. Mousson, A. (1888). "Coquilles recueillies dans le Sud-Ouest de l'Afrique par M. le Dr. H. Schinz, déterminée par Alb. Mousson". Journal de Conchyliologie. 35 (4): 299. Retrieved 3 June 2025. This article incorporates text from this source, which is in the public domain .

• Connolly, M. (1939). A monographic survey of South African non-marine Mollusca. Annals of the South African Museum. 33: 1-660.
• Appleton, C.C. (1996). Freshwater molluscs of southern Africa. University of Natal Press: Pietermaritzburg. Pp. 1–64.

External links

• Brown, D. S.; Curtis, B. A.; Bethune, S.; Appleton, C. C. (1992). "Freshwater snails of East Caprivi and the lower Okavango River Basin in Namibia and Botswana". Hydrobiologia. 246 (1): 16. Retrieved 3 June 2025.