Thickshell pondsnail

Stagnicola utahensis, common name the thickshell pondsnail, is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Lymnaeidae, the pond snails. This species is endemic to Utah Lake in the United States. The last living snails were found in the 1930s.

Thickshell pondsnail
Drawing of apertural view of the shell of Stagnicola utahensis.

Critically endangered, possibly extinct  (IUCN 3.1)[1]
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Gastropoda
(unranked):
clade Heterobranchia
clade Euthyneura
clade Panpulmonata
clade Hygrophila
Superfamily:
Lymnaeoidea
Family:
Lymnaeidae
Subfamily:
Lymnaeinae
Genus:
Stagnicola
Species:
S. utahensis
Binomial name
Stagnicola utahensis
(Call, 1884)[2]
Synonyms

Radix ampla var. utahensis Call, 1884
Radix utahensis (Call, 1884)
Galba utahensis (Call, 1884)
Polyrhytis utahensis (Call, 1884)

Shell description

The shell is globose, somewhat umbilicated and irregularly costate. The color of the shell is light horn and nearly pellucid. The spire is rather small and conical. The shell has from 4 to 4 and half convex whorls, that are somewhat flattened above, giving rather a shouldered appearance to the whorls. Whorls are rapidly increasing in size. The last whorl is inflated, with numerous rather marked transverse costae and minutely wrinkled. The suture is somewhat deep, regularly impressed.[3]

The aperture is elongately ovate, effuse, approaching patulous and pearly white within. The outer lip is simple and its margin is connected by a slight calcareous deposit. The columella is somewhat twisted, but straight in front.[3]

The average width of the shell of Stagnicola utahensis is 7.10 mm. The average height of the shell is 13.40 mm. The maximum width of the shell is 8.88 mm. The height of the shell is 16.82 mm. The width of the aperture is 5.90 mm. The height of the apeture is 9.00 mm.[3]

  • Drawing of apical view of the shell
  • Drawing of lateral view of the shell

Anatomy

The anatomy of the radula was not published.[3] (cf.[4])

Distribution

This species is endemic to North America and it is known only from Utah Lake. The type locality is Lake Utah, Lehi, Utah.[3]

The species was already considered "rare" in Utah Lake in the 1880s.[3]

The most recent living examples were found in the early 1930s.[4]

Ecology

This species was associated with abundant individuals of the snails Valvata utahensis and Fluminicola fusca and with the bivalve Sphaerium dentatum.[3]

References

This article incorporates public domain text from reference [3]

  1. Cordeiro, J. & Perez, K. (2012). "Stagnicola utahensis". The IUCN Red List of Threatened Species. IUCN. 2012: e.T20706A2773078. doi:10.2305/IUCN.UK.2012.RLTS.T20706A2773078.en. Retrieved 14 December 2017.
  2. Call R. E. (1884). Bull. U. S. Geol. Sur. 11: p. 47, plate VI., figures 7-9.
  3. Call R. E. (1886). "On certain recent, quaternary, and new fresh-water Mollusca". Proceeding Davenport Academy of Natural Sciences 5: page 5, plate I, figure 7-9.
  4. THICKSHELL PONDSNAIL. Utah Division of Wildlife Resources, accessed 21 July 2009.
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