Georissa

{{Short description|Genus of gastropods}} {{Automatic taxobox | image = Georissa shikokuensis 001.jpg | image_caption = ''Georissa shikokuensis'' | taxon = Georissa | authority = Blanford, 1864<ref>Blanford W. T. (1864). "On the Classification of the Cyclostomacea of Eastern Asia". ''Annals and Magazine of Natural History'' (3)'''13''': [https://archive.org/stream/s3annalsmagazine13londuoft#page/440/mode/2up 441]-465, [https://archive.org/stream/s3annalsmagazine13londuoft#page/462/mode/2up page 463].</ref> |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.<ref name="WoRMS">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</ref>

==Description== (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.<ref>{{cite journal |last1=Blanford |first1=W.T. |title=On the classification of the Cyclostomacea of eastern Asia |journal=Annals and Magazine of Natural History |date=1864 |volume=3 |issue=13 (78) |page=463 |url=https://www.biodiversitylibrary.org/page/22217703 |access-date=21 April 2025}} {{source-attribution}}</ref>

==Distribution== 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.<ref>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</ref><ref>Schilthuizen M., Cabanban A. S. & Haase M. (2005). "Possible speciation with gene-flow in tropical cave snails". ''Journal of Zoological Systematics'' '''43''': 133-138. {{doi|10.1111/j.1439-0469.2004.00289.133-138}}.</ref>

==Species== Species within the genus ''Georissa'' include: {{div col}} *''Georissa anyiensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys">{{cite journal |last1=Khalik |first1=Mohd Zacaery |last2=Hendriks |first2=Kasper |last3=Vermeulen |first3=Jaap J. |last4=Schilthuizen |first4=Menno |title=A molecular and conchological dissection of the "scaly" Georissa of Malaysian Borneo (Gastropoda, Neritimorpha, Hydrocenidae) |journal=ZooKeys |date=9 July 2018 |issue=773 |pages=1–55 |doi=10.3897/zookeys.773.24878|doi-access=free |pmid=30026659 |pmc=6048177 |bibcode=2018ZooK..773....1K }}</ref> * ''Georissa bangueyensis'' E. A. Smith, 1895 *''Georissa bauensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys"/> * ''Georissa biangulata'' Quadras & Möllendorff, 1894 * ''Georissa borneensis'' E. A. Smith, 1895 * ''Georissa elegans'' Quadras & Möllendorff, 1894 * ''Georissa everetti'' E. A. Smith, 1895 * ''Georissa filiasaulae'' Haase & Schilthuizen, 2007<ref name="Haase 2007">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. {{doi|10.1093/mollus/eym020}}.</ref> * ''Georissa gomantongensis'' E.A. Smith, 1894 * ''Georissa hadra'' Thompson & Dance, 1983 * ''Georissa hosei'' Godwin-Austen, 1889 * ''Georissa japonica'' Pilsbry, 1900<ref name="Noseworthy 2007">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. [https://www.academia.edu/7570561/A_Catalogue_of_the_Mollusks_of_Jeju_Island_South_Korea PDF].</ref> *''Georissa kinabatanganensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys"/> * ''Georissa kobelti'' Gredler, 1902 * ''Georissa laevigata'' Quadras & Möllendorff, 1894 * ''Georissa laseroni'' (Iredale, 1937) * '''Georissa mawsmaiensis''' Das & Aravind, 2021 * ''Georissa monterosatiana'' Godwin-Austen & Neville, 1879 *''Georissa muluensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys"/> * ''Georissa niahensis'' Godwin-Austen, 1889 * ''Georissa pachysoma'' Vermeulen & Junau, 2007 * ''Georissa purchasi'' * ''Georissa pyrrhoderma'' Thompson & Dance 1983 * ''Georissa pyxis'' (Benson, 1856) - type species of the genus ''Georissa''<ref name="Haase 2007"/> * ''Georissa rufula'' von Möllendorf, 1900 * ''Georissa saulae'' (van Benthem-Jutting, 1966) * ''Georissa scalinella'' (van Benthem-Jutting, 1966) * ''Georissa semisculpta'' *''Georissa sepulutensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys"/> * ''Georissa shikokuensis'' Amano, 1939 * ''Georissa silaburensis'' Khalik, Hendriks, Vermeulen & Schilthuizen, 2018<ref name="GeorissasZooKeys"/> * ''Georissa similis'' E.A. Smith, 1894 * ''Georissa vesta'' Thompson & Dance, 1983 * ''Georissa williamsi'' Godwin-Austen, 1889 (including ''Georissa hungerfordi'') {{div col end}}

==References== {{Reflist}}

== External links == * {{Commons category-inline|position=left|Georissa}}

Category:Gastropod genera Category:Hydrocenidae Category:Gastropods of Asia Category:Molluscs of Oceania Category:Taxonomy articles created by Polbot Category:Taxa named by William Thomas Blanford

Georissa

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