Keys to New Zealand land snails
We are developing a series of identification keys to the New Zealand land snail fauna.
These keys are developed with Lucid software. To run the keys, simply click on the appropriate image.
Acknowledgements: These keys were developed with financial assistance from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme and in part by the New Zealand Foundation for Research, Science and Technology, under the Defining New Zealand’s Land Biota contract. The TFBIS Programme is funded by the Government specifically to help achieve outcomes in the New Zealand Biodiversity Strategy, and is administered by the Department of Conservation. The purpose of the TFBIS Programme is to support the conservation of New Zealand’s indigenous biodiversity by increasing awareness of, and access to, data and information about indigenous biodiversity and how to conserve it. The Defining New Zealand’s Terrestrial Biota Programme supports New Zealand’s major biosystematics capability relating to terrestrial biota, both indigenous and introduced, with research on description, distribution, evolutionary relationships, genetic diversity, and ecological links. The programme is built around nationally significant databases and collections relating to plants, invertebrates, fungi and bacteria, and the ethnobotanical database and living plant collection.
1. Key to Genus Cytora
In the New Zealand land snail fauna, the Cyclophoroidea are represented by the indemic genera Liarea Gray, 1852 and Cytora Kobelt & Möllendorff, 1897. The systematic affinities of these genera has not been fully resolved, reflecting in large part the poor understanding of the evolutionary history and unstable higher systematics of cyclophoraceans globally (see Barker 2001). Presently Cytora and Liarea are assigned to the family Pupinidae.
The genus Cytora was recently revised by Marshall and Barker
(2007), who recognised a total of 42 species. This key is based on that revision.
Cytora are litter-dwelling detritivores that, with the exception of an occasional case of arborealism in some species, occur on the forest floor. Cytora is widely distributed in New Zealand, with species represented in the Three Kings, North, South, Stewart and Auckland islands. Highest species richness occurs in the northern North Island and north-western South Island. Cytora species are notably absent from much of mid-Canterbury (including Banks Peninsula) and Central Otago in the South Island, the upper montane areas of both North and South islands, and from the offshore Kermadec, Chatham and Campbell islands.
Several Cytora species are identified as of conservation concern in the New Zealand Threat Classification System Lists (Hitchmough et al. 2007) (also see Marshall & Barker 2007). Robust identification of species is an essential first step to conservation management.
How to cite: Barker GM, Marshall BA 2008. Keys to New Zealand land snails
– 1. Genus Cytora. Published online by Landcare Research and the Museum of New Zealand Te Papa Tongarewa. http://www.landcareresearch.co.nz/research/biocons/mollusc/identification.asp
References and suggested future reading:
Barker GM 2001. Gastropods on land: phylogeny, diversity and adaptive morphology. In: Barker GM ed. Biology of terrestrial molluscs. Wallingford, CABI International. Pp. 1–146.
Barker GM 2005. The character of the New Zealand land snail fauna and communities: some evolutionary and ecological perspectives. Records of the Western Australian Museum, Supplement 68: 53–102.
Barker GM, Mayhill PC 1999. Patterns of diversity and habitat relationships in terrestrial mollusc communities of the Pukeamaru Ecological District, northeastern New Zealand. Journal of Biogeography 25: 215–238.
Climo FM 1970. The systematic position of Cytora Kobelt & Möllendorff, 1897 and Liarea Pfeiffer, 1853 (Mollusca: Mesogastropoda). Transactions of the Royal Society of New Zealand, Biological Sciences 12: 213–216.
Climo FM 1973. The systematics, biology and zoogeography of the land snail fauna of Great Island, Three Kings Group, New Zealand. Journal of the Royal Society of New Zealand 3: 565–628.
Climo FM 1975. The land snail fauna. In: Kuschel G. ed. Biogeography and ecology in New Zealand. The Hague, Dr W. Junk. Pp. 459–492.
Hitchmough R, Bull L, Cromarty P 2007. New Zealand Threat Classification System lists 2005. Wellington, Department of Conservation. 194 p.
Marshall BA, Barker GM 2007. A revision of New Zealand landsnails of the genus Cytora Kobelt & Möllendorff, 1897 (Mollusca: Gastropoda: Pupinidae). Tuhinga 18: 49–113.
2. Key to Genus Allodiscus and conchologically similar land snails
The New Zealand land snail fauna includes many Punctoidea. Collections presently house at least 450 species-level taxa of the family Charopidae from New Zealand. Only 210 of these species have been formally described (Barker 2005). Discocharopa aperta (Moellendorff, 1888) is represented in the New Zealand region only in the Kermadec Islands, and its range extends widely in the Pacific (Solem 1982). All other New Zealand charopid species are endemic.
Many charopids are considered of conservation concern (Hitchmough et al. 2007). However, in many groups in the New Zealand Charopidae proper assessment of conservation status has been hindered by the lack of modern systematic treatment and the absence of formal taxonomy of many recognised but presently undescribed species.
Marshall and Barker recently revised the New Zealand endemic genera Allodiscus Pilsbry, 1892 (9 species in Allodiscus sensu stricto; 42 species Allodiscus sensu lato) and Pseudallodiscus Climo, 1971 (1 species). In that revision, Hirsutodiscus Climo, 1971 (1 species), previously treated as a subgenus in Allodiscus, was elevated to generic status. Furthermore, three new genera were erected for species previously assigned formally or informally to genus Allodiscus, namely Granallodisus Marshall and Barker, 2008 (3 species); Costallodiscus Marshall and Barker, 2008 (3 species); and Canallodiscus Marshall and Barker, 2008 (3 species).
These land snails are litter-dwelling detritivores of forests and shrublands.
How to cite: Barker GM, Marshall BA 2008. Keys to New Zealand land snails – 2. Genus Allodiscus and conchologically similar land snails. Published online by Landcare Research and the Museum of New Zealand Te Papa Tongarewa. http://www.landcareresearch.co.nz/research/biocons/mollusc/identification.asp
References and suggested future reading:
Barker GM 2005. The character of the New Zealand land snail fauna and communities: some evolutionary and ecological perspectives. Records of the Western Australian Museum, Supplement 68: 53–102.
Hitchmough R, Bull L, Cromarty P 2007. New Zealand Threat Classification System lists 2005. Wellington, Department of Conservation. 194 p.
Marshall BA, Barker GM 2008. A revision of the New Zealand landsnails referred to Allodiscus Pilsbry, 1892 and Pseudallodiscus Climo, 1971, with the introduction of three new genera (Mollusca: Gastropoda: Charopidae). Tuhinga (in press).
Solem A 1982. Endodontid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part 2. Families Punctidae and Charopidae, zoogeography. Chicago, ILL, USA, Field Museum of Natural History. 336 p.