Georissa

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Georissa
Georissa shikokuensis
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Cycloneritida
Family: Hydrocenidae
Genus: Georissa
Blanford, 1864[1]
Synonyms
  • Chondrella Pease, 1871 (original rank)
  • Georissa (Chondrella) Pease, 1871 alternative representation
  • Georissa (Georissa) W. T. Blanford, 1864 alternative representation
  • Georissa (Georissopsis) Pilsbry & Hirase, 1908 alternative representation
  • Hydrocena (Georissa) W. T. Blanford, 1864
  • Omphalorissa Wenz, 1938
  • Petrorissa Habe, 1958

Georissa is a genus of minute land snails, terrestrial gastropod mollusks in the family Hydrocenidae.[2]

Description

[edit | edit source]

(Original description in Latin) The shell is imperforate or scarcely perforate. It is very small, and conical, displaying an amber-colored or reddish hue. It is usually spirally grooved or striated.

The operculum appears semi-oval, lacking any trace of spiral structure, and presents eccentric striations. It is testaceous (shell-like) and transparent.

The animal is small and is equipped with hemispherical lobes in place of tentacles. Its eyes are normal, and its foot is short and rounded.[3]

Distribution

[edit | edit source]

Although the species are best known for living on the surface of limestone rocks, they are often also found in and on the vegetation and on non-calcareous rocks. One species, Georissa filiasaulae, is cavernicolous. It is only known from two caves in the Sepulut area of Sabah, Malaysian Borneo, where its above-ground sister species, Georissa saulae, inhabits the rocks outside of the cave, and is connected to the cave snail via narrow zones of hybridization at the cave entrances. Possibly, G. filiasaulae has evolved without ever having been fully separated from its ancestor, a process known as speciation-with-gene-flow.[4][5]

Species

[edit | edit source]

Species within the genus Georissa include:

References

[edit | edit source]
  1. ^ Blanford W. T. (1864). "On the Classification of the Cyclostomacea of Eastern Asia". Annals and Magazine of Natural History (3)13: 441-465, page 463.
  2. ^ MolluscaBase eds. (2025). MolluscaBase. Georissa W. T. Blanford, 1864. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=818273 on 2025-04-21
  3. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ Schilthuizen M., Rutten E. J. M. & Haase M. (2012). "Small-scale genetic structuring in a tropical cave snail and admixture with its above-ground sister species". Biological Journal of the Linnean Society 105: 727-740. doi:10.1111/j.1095-8312.2011.01835.x
  5. ^ Schilthuizen M., Cabanban A. S. & Haase M. (2005). "Possible speciation with gene-flow in tropical cave snails". Journal of Zoological Systematics 43: 133-138. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
  6. ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ a b Haase M. & Schilthuizen M. (2007). "A new Georissa (Gastropoda: Neritopsina: Hydrocenidae) from a limestone cave in Malaysian Borneo". Journal of Molluscan Studies 73(3): 215-221. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
  8. ^ Noseworthy R. G., Lim N.-R. & Choi K.-S. (2007). "A Catalogue of the Mollusks of Jeju Island, South Korea". Korean Journal of Malacology 23(1): 65-104. PDF.
[edit | edit source]
  • Error creating thumbnail: File missing Media related to Lua error in Module:Commons_link at line 62: attempt to index field 'wikibase' (a nil value). at Wikimedia Commons

Lua error in Module:Taxonbar at line 165: attempt to index field 'wikibase' (a nil value).