Lanistes Explained

Lanistes is a genus of freshwater snails which have a gill and an operculum, aquatic gastropod mollusks in the family Ampullariidae, the apple snails.^[1]

Distribution

The distribution of the genus Lanistes includes Africa and Madagascar.^[2]

Description

Lanistes has a unique anatomy among the Ampullariidae: it has a "hyperstrophic" sinistral shell. This means that the body of the snail is dextral (as in all other ampullariids), but the shell appears to be sinistral. However the sinistral appearance stems from the fact that the rotation of the shell as it grows is in an upward direction rather than the usual downward direction.^[3]

Species

Three^[2] subgenera have been recognized, based on shell differences: Lanistes sensu stricto, Meladomus and Leroya. These subgenera are not used in recent works.^[2]

Extant species within the genus Lanistes include:

• Lanistes alexandri (Bourguignat, 1889)^[2]
• Lanistes ambiguus Martens, 1866
• Lanistes bernardianus (Morelet, 1860)
• Lanistes beseneckeri Schütt in Schütt & Besenecker, 1973 †
• Lanistes bicarinatus Germain, 1907^[2]
• Lanistes bloyeti (Bourguignat, 1889)
• Lanistes boltenianus (Röding, 1798) - synonym: Lanistes carinatus (Olivier, 1804)^[4]
• Lanistes chaperi (Kobelt, 1912)
• Lanistes ciliatus Martens, 1878^{[5] [2]}
• Lanistes congicus O. Boettger, 1891^{[5] [2]}
• Lanistes deguerryanus (Bourguignat, 1889)
• Lanistes ellipticus Martens, 1866^{[5] [2]}
• Lanistes farleri Craven, 1880^{[5] [2]}
• Lanistes fultoni (Kobelt, 1912)
• Lanistes grasseti (Morelet, 1863)^[2]
• Lanistes graueri Thiele, 1911^{[5] [2]}
• Lanistes intortus Martens, 1877^{[5] [2]}
• Lanistes jouberti (Bourguignat, 1888)
• Lanistes letourneuxi (Bourguignat, 1879)
• Lanistes libycus (Morelet, 1848)^{[5] [2]}
  • Lanistes libycus var. albersi
  • Lanistes libycus form bernardianus^[2] or as Lanistes bernardianus (Morelet, 1860)^[5]
• Lanistes magnus Furtado, 1886
• Lanistes nasutus Mandahl-Barth, 1972^{[5] [2]}
• Lanistes neavei Melvill & Standen, 1907^{[5] [2]}
• Lanistes neritoides Brown & Berthold, 1990^{[5] [2]}
• Lanistes nitidissimus (Bourguignat, 1889)
• Lanistes nsendweensis (Dupuis & Putzeys, 1901)^[2]
• Lanistes nyassanus Dohrn, 1865^[2]
• Lanistes ovatus (Olivier, 1804)
• Lanistes ovum Peters in Troschel, 1845^[2] - synonyms: Lanistes magnus Furtado; Lanistes olivaceus (Sowerby); Lanistes procerus; Lanistes elatior Martens, 1866; Lanistes ovum bangweolicus Haas, 1936; Lanistes connollyi Pain, 1954^[2] Lanistes ovum adansoni; Lanistes olivaceus var. ambiguus
• Lanistes palustris (Morelet, 1864)
• Lanistes pfeifferi (Bourguignat, 1879)
• Lanistes pilsbryi Walker, 1925
• Lanistes pseudoceratodes (Wenz, 1928)^[5]
• Lanistes purpureus (Jonas, 1839)^{[5] [2]}
• Lanistes solidus Smith, 1877^{[5] [2]}
• Lanistes stuhlmanni Martens, 1897^{[5] [2]}
• Lanistes varicus (Müller, 1774) - synonyms: Lanistes adansoni Kobelt, 1911; Lanistes millestriatus Pilsbry & Bequaert, 1927^[2]

Fossil species within the genus Lanistes include:

• † Lanistes asellus van Damme & Pickford, 1995
• † Lanistes bishopi Gautier

• † Lanistes gautieri van Damme & Pickford, 1995
• † Lanistes gigas van Damme & Pickford, 1995
• † Lanistes hadotoi van Damme & Pickford, 1995^[6]
• † Lanistes heynderycxi van Damme & Pickford, 1995^[6]

• † Lanistes nkondoensis van Damme & Pickford, 1995^[6]
• † Lanistes olukaensis^[6]

• † Lanistes senuti van Damme & Pickford, 1995^[6]
• † Lanistes trochiformis van Damme & Pickford, 1995^[6]

External links

• Animation showing how the "hyperstrophic" sinistral shell evolved from a shell with normal orientation
• Schultheiß R., Van Bocxlaer B., Wilke T. & Albrecht C. (2009). "Old fossils–young species: evolutionary history of an endemic gastropod assemblage in Lake Malawi". Proceedings of the Royal Society B 276(1668): 2837-2846. .

Notes and References

1. Bouchet, P.; Neubauer, Thomas A. (2015). Lanistes Montfort, 1810. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=820447 on 2015-11-11
2. Brown D. S. (1994). Freshwater Snails of Africa and their Medical Importance. Taylor & Francis. .
3. http://www.applesnail.net/content/anatomy/shell.php#hyperstrophic "Shell"
4. Bouchet, P. (2016). Lanistes boltenianus (Röding, 1798). In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=843296 on 2017-06-06
5. http://www.applesnail.net/content/lanistes.htm "Lanistes"
6. van Damme D. & Pickford M. (1995). "The late Cenozoic ampullariidae (mollusca, gastropoda) of the Albertine Rift Valley (Uganda-Zaire)". Hydrobiologia 316(1): 1-32. .