Georissa Explained

Georissa is a genus of minute land snails, terrestrial gastropod mollusks in the family Hydrocenidae. 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.^{[1] [2]}

Species

Species within the genus Georissa include:

• Georissa anyiensis Khalik, Hendriks, Vermeulen & Schilthuizen, 2018^[3]
• Georissa bangueyensis E. A. Smith, 1895
• Georissa bauensis Khalik, Hendriks, Vermeulen & Schilthuizen, 2018^[3]
• 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^[4]
• Georissa gomantongensis E.A. Smith, 1894
• Georissa hadra Thompson & Dance, 1983
• Georissa hosei Godwin-Austen, 1889
• Georissa japonica Pilsbry, 1900^[5]
• Georissa kinabatanganensis Khalik, Hendriks, Vermeulen & Schilthuizen, 2018^[3]
• 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^[3]
• 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^[4]
• 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^[3]
• Georissa shikokuensis Amano, 1939
• Georissa silaburensis Khalik, Hendriks, Vermeulen & Schilthuizen, 2018^[3]
• Georissa similis E.A. Smith, 1894
• Georissa vesta Thompson & Dance, 1983
• Georissa williamsi Godwin-Austen, 1889 (including Georissa hungerfordi)

Notes and References

1. 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
2. Schilthuizen M., Cabanban A. S. & Haase M. (2005). "Possible speciation with gene-flow in tropical cave snails". Journal of Zoological Systematics 43: 133-138. .
3. Khalik . Mohd Zacaery . Hendriks . Kasper . Vermeulen . Jaap J. . Schilthuizen . Menno . A molecular and conchological dissection of the "scaly" Georissa of Malaysian Borneo (Gastropoda, Neritimorpha, Hydrocenidae) . ZooKeys . 9 July 2018 . 773 . 1–55 . 10.3897/zookeys.773.24878. free . 30026659 . 6048177 . 2018ZooK..773....1K .
4. 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. .
5. 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.