Vertigo (Vertigo) moulinsiana | Desmoulin's Whorl Snail
|Overall Assessment of Conservation Status||Inadequate|
|Overall Trend in Conservation Status||Declining|
IUCN Conservation Status
|Ireland (1)||Endangered [A4c]|
|Europe (2)||Vulnerable [A2ac]|
|Global (2)||Vulnerable [A2ac]|
Protected by the following legal instruments:
- Habitats Directive [92/42/EEC] Annex II
Desmoulin’s Whorl-snail (Vertigo moulinsiana) has a black head and tentacles and a pale grey body. The shell is translucent and varies from a pale yellow to a reddish-brown occasionally with dark banding. Old shells are a greyish-brown.Very fine striations on the shell are not immediatley obvious but may be seen with a hand lens.
Source: Killeen I.J., 2003.
Shell size is to 2.7mm only, but it is still the largest native Whorl-snail in Ireland. Shell mouth opening is to the right of the shell (dextral), with 4 teeth obvious at the shell mouth. The lip of the shell is relatively large and flares out, and is connected to teeth by pale opaque 'callosities' (thickenings of the shell).
The whorl nearest the mouth is the largest making up almost 66% of the shell. This description is for a fully developed adult, younger individuals will vary in shell shape being more conical and the teeth at the shell mouth being less well developed.
Sources: Cameron R., 2003; Killeen I.J., 2003.
Adult habitat & habits
Optimal habitat is where water level is at or slightly above ground level for much of the year, with a good cover of tall sedges and grasses. Most often found in calcareous conditions.
Source:Moorkens,E.A.& Killeen, I.J., 2011.
Habitats include but are not necessarily limited to;
- Rich fen and flush (PF1)
- Reed and large sedge swamps (FS1)
- Tall-herb swamps (FS2)
- Marsh (GM1)
- Canals (FW3).
- Riparian zone.
The species is hermaphrodite and is capable of outcrossing and also capable of self-fertilization. There is little available research on the life cycle of Vertigo moulinsiana.
Studies of British populations suggest high juvenile mortality rates in winter resulting in low densities and numbers with majority adult populations by mid-June. Numbers of juveniles increase through summer forming majority juvenile populations by mid-October.
Source: Killeen (2003)
Life span to 1-3 years, but majority dying in the year after hatching.
Source: Myzyk, S., 2003.
|THREAT||ARTICLE 17 CODE||RANKING|
|Dredging / removal of limnic sediments||J02.02.01||Low|
|Management of aquatic and bank vegetation for drainage purposes||J02.10||Low|
|Species composition change (succession)||K02.01||Low|
|Infilling of ditches, dykes, ponds, pools, marshes or pits||J02.01.03||Low|
|Reclamation of land from sea, estuary or marsh||J02.01.02||Low|
|Abandonment of pastoral systems, lack of grazing.||A04.03||Low|
|Landfill, land reclamation and drying out, general||J02.01||Low|
*In the species notes for the Article 17 Reporting 2007-2012 period it its specified that this relates to 'management and possible re-opening of disused canals'.
Source: NPWS 2013.
In the IUCN European Red List for this species Version 2014.2 some additional threats are identified at a European level which include;
- Agricultural and forestry effluents
- Wood and pulp plantations
- Residential and commercial development
- Climate change and severe weather
Source: Killeen, I., Moorkens, E. & Seddon, M., 2012.
In the Article 17 Habitats Directive reporting for the period 2007-2012 no Conservation Measures were outlined other than;
- Continued legal protection of the species and its habitats inside Natura 2000 sites designated for the species.
Desmoulin’s Whorl Snail occurs in Europe from Ireland to Russia, and is also found in north Africa however its distribution is mainly concentrated in western and Central Europe.
Source: Killeen, I., Moorkens, E. & Seddon, M.B., 2011.
Records submitted to Data Centre in 2019
The following map is interactive. If you would prefer to view it full screen then click here.
How can you help
The National BiodiversityData Centre is trying to improve our knowledge on the distribution of Desmoulin's Whorl Snail in Ireland. Should you observe this species, please submit sightings to add to the database. Detailed observations will assist us gaining a better insight into where Desmoulin's Whorl Snail is most abundant in Ireland and we might also be able to detect regional variations. Please submit any sightings and photographs at:
All records submitted online can be viewed on Google Maps – once checked and validated these will beadded to the database and made available for conservation and research.
For further information contact Dr. Liam Lysaght firstname.lastname@example.org
Byrne, A., Moorkens, E.A., Anderson, R., Killeen, I.J. & Regan, E.C. (2009) Ireland Red List No. 2 – Non-Marine Molluscs. National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government, Dublin, Ireland.
Cameron R., (2003) Land Snails in the British Isles. Field Studies Council.
Fossitt, J.A. (2001) A Guide to Habitats in Ireland. The Heritage Council.
Killeen I.J. (2003). Ecology of Desmoulin’s Whorl Snail.Conserving Natura 2000 Rivers Ecology Series No. 6. English Nature, Peterborough.
Killeen, I., Moorkens, E. & Seddon, M. 2012. Vertigo moulinsiana. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 10 September 2014.
Myzyk S., (2011). Contribution to the biology of ten vertiginid species. Folia Malacologica Vol. 19 (2),55-80.
NPWS (2013) The Status of EU Protected Habitats and Species in Ireland. Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.