Hydrocenidae

Hydrocenidae is a poorly known taxonomic family of minute land snails or cave snails with an operculum, terrestrial gastropod mollusks or micromollusks in the clade Cycloneritimorpha.

These tiny cave snails are not closely related at all to the air-breathing or pulmonate land snails. These hydrocenid snails are more closely related to the marine and freshwater snails known as nerites, the Neritidae.

Hydrocenidae is the only family in the superfamily Hydrocenoidea. This family has no subfamilies according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005.

Description

The animal have no gill, but a pulmonary cavity.^[1] Tentacles are short and large.^[1] The eyes are prominent, situated at the upper or outer base of the tentacles.^[1] The foot is short, oval and obtuse.^[1] The denticle (tiny teeth) of radula have the formula ∞ 1, (1 + 1 + 1), 1 ∞.^[1] The central denticles are small and elongated.^[1] The lateral tooth is rather large, straight, without a cusp.^[1] The numerous lateral teeth are denticulate, and arranged in very oblique series.^[1]

The shell is imperforate, conic and globular.^[1] Whorls are convex.^[1] The spire is short.^[1] The peristome is continuous.^[1] The columella is callous.^[1] The lip is not reflexed.^[1] The operculum is calcareous, ornamented with striae which are concentric to the nucleus.^[1] The inner side of the operculum is with a prominent apophysis arising from the nucleus.^[1]

Genera

Genera and species within the family Hydrocenidae include:^[2]

• Genus Georissa Blanford, 1884
• Genus Hydrocena Pfeiffer, 1841
  • Hydrocena cattaroense (Pfeiffer, 1841)
• Genus Omphalorissa Iredale, 1933
  • Omphalorissa purchasi (Pfeiffer, 1862)
• Monterissa Iredale, 1944
  • Monterissa gowerensis

References

This article incorporates public domain text from the reference.^[1]