Hydrocenidae is a

taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of minute

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 molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...

s or

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

snails with an operculum,

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s or

micromollusk A micromollusc is a shelled mollusc which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine molluscs, although in addition, numerous species of land snails and freshwater molluscs also ...

s in the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

Cycloneritimorpha Cycloneritida (nerites and false-limpets) is an order of land snails, freshwater snails, and sea snails.MolluscaBase eds. (2020). MolluscaBase. Cycloneritida. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/a ...

. Hydrocenidae are widespread across the Palearctis and Africa, but reach their highest diversity in the Oriental, Australian, and Oceanian regions. The family is poorly known and has not been revised in the past 140 years and as a consequence, the status of the various genus names (including ''

Georissa ''Georissa'' is a genus of minute land snails, terrestrial gastropod mollusks in the family Hydrocenidae.MolluscaBase eds. (2025). MolluscaBase. Georissa W. T. Blanford, 1864. Accessed through: World Register of Marine Species at: https://www.mar ...

'') is uncertain. 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. Tentacles are short and large. The eyes are prominent, situated at the upper or outer base of the tentacles. The foot is short, oval and obtuse. The denticle (tiny teeth) of

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

have the formula ∞ 1, (1 + 1 + 1), 1 ∞. The central denticles are small and elongated. The lateral tooth is rather large, straight, without a cusp. The numerous lateral teeth are denticulate, and arranged in very oblique series. The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

is imperforate, conic and globular.

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). In nature File:Photograph and axial plane floral diagram ...

are convex. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

is short. The peristome is continuous. The

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

is callous. The lip is not reflexed. The operculum is calcareous, ornamented with striae which are concentric to the nucleus. The inner side of the operculum is with a prominent apophysis arising from the nucleus.

Genera

Genera and species within the family Hydrocenidae include: * Genus ''

'' Blanford, 1884 * Genus ''

Hydrocena ''Hydrocena'' is a genus of gastropods belonging to the family Hydrocenidae. The genus has almost cosmopolitan distribution. Species: *''Hydrocena atavina'' *'' Hydrocena bridgesi'' *''Hydrocena cattaroensis'' *''Hydrocena cerea'' *''Hydro ...

'' Pfeiffer, 1841 ** ''

Hydrocena cattaroense ''Hydrocena'' is a genus of gastropods belonging to the family Hydrocenidae. The genus has almost cosmopolitan distribution. Species: *''Hydrocena atavina'' *'' Hydrocena bridgesi'' *''Hydrocena cattaroensis'' *''Hydrocena cerea'' *'' Hydr ...

'' (Pfeiffer, 1841) **''?

Hydrocena praecursor ''Hydrocena'' is a genus of gastropods belonging to the family Hydrocenidae. The genus has almost cosmopolitan distribution. Species: *'' Hydrocena atavina'' *'' Hydrocena bridgesi'' *''Hydrocena cattaroensis'' *'' Hydrocena cerea'' *'' H ...

'' Tingting and Neubauer, 2021

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. Th ...

, Myanmar,

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

* Genus '' Omphalorissa'' Iredale, 1933 ** ''

Omphalorissa purchasi ''Georissa purchasi'' is a species of small land snail, a terrestrial gastropod mollusc in the family Hydrocenidae. The type specimen is stored in the Imperial Natural History Museum, Vienna. Description The shell is minute, globosely conical ...

'' (Pfeiffer, 1862) * ''

Monterissa ''Monterissa'' is a genus of minute cave snails with an operculum, gastropod mollusks in the family Hydrocenidae. Species Species within the genus ''Monterissa'' include: * ''Monterissa gowerensis ''Monterissa gowerensis'', also known as t ...

'' Iredale, 1944 ** ''

Monterissa gowerensis ''Monterissa gowerensis'', also known as the Lord Howe microturban, is a species of small cave snails with an operculum, gastropod mollusks in the family Hydrocenidae. Description The globosely turbinate shell of adult snails is 2.1–2.4 ...

References

This article incorporates public domain text from the reference. Suter H. (1913). ''Manual of the New Zealand Mollusca''. Wellington, 1120 pp
page 175
{{Taxonbar, from=Q3138813 Cave snails