Lagoon snail (Paludinella globularis)
Three live shells and one empty one of Paludinella globularis.
Photographer: Dennis R. Seaward Copyright: Dennis R. Seaward
One animal crawling. Eyes showing in centre of lobed tentacles.
Photographer: Dennis R. Seaward Copyright: Dennis R. Seaward
Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
| Researched by | Nicola White | Refereed by | Dennis R. Seaward |
| Authority | (Hanley in Thorpe, 1844) | ||
| Other common names | - | Synonyms | Rissoa littorea Jeffreys, 1856, Paludinella littorina (Delle Chiaje, 1828) sensu Philippi, 1841, Cingula globularis Hanley in Thorpe, 1844 |
Summary
Description
A small, globose snail that grows up to 2 mm high. The shell is glossy and semitransparent. The animal is pale grey and appears whitish through the shell. The tentacles are short and stubby with eyes seen as two black dots. It is often easily confused with juvenile Littorina saxatilis.
Recorded distribution in Britain and Ireland
Recorded from the Isle of Wight, the Fleet, North Devon, South Devon, Pembrokeshire, Cornwall and Isles of Scilly.Global distribution
Primarily a Mediterranean species (absent from the Black Sea) which extends along Eastern Atlantic coasts from Madeira north to a limit on the south coast of England.Habitat
Occurs in crevices, caves, under rocks and in lagoonal shingle, at or just above the water line. The caves are usually sheltered and the surface of the walls colonized by green and red algal films and soft crusts. Sites in caves are associated with lithologies which are foliated and fissile allowing the development of fissures and crevices.Depth range
Not relevantIdentifying features
- Tiny globose tarn-coloured shell.
- Broad bifid snout.
- Tentacles broad, joined and rounded, with a black eye in the centre of each left and right lobe.
Additional information
The pulmonate Otina ovata is a frequent associate of Paludinella globularis, in caves etc. In shingle, it often occurs with the pulmonates Ovatella myosotis and (slightly lower on the shore) Leucophytia bidentata, and the prosobranch Truncatella subcylindrica.
Kadolsky (2012) showed that the original description of type species of Paludinella littorina (originally described as Helix littorina Delle Chiaje, 1828), was most probably based on small specimens of Melarhaphe neritoides (Linnaeus, 1758). The original type description was, therefore, incorrect. In addition, Pfeiffer (1841) based the genus Paludinella on the taxonomic extension given to that name by Philippi (1841), i.e. a misidentified type species. Furthermore, Kadolsky noted that the correct name for specimens of P. littorina is, in fact, P. globularis. Therefore, for specimens of Paludinella littorina of authors, non Delle Chiaje, Kadolsky restored the name Paludinella globularis and designated the latter as type species of Paludinella (Kadolsky, 2012; Bouchet, 2012).
Listed by
Biology review
Taxonomy
| Phylum | Mollusca | Snails, slugs, mussels, cockles, clams & squid |
| Class | Gastropoda | Snails, slugs & sea butterflies |
| Order | Littorinimorpha | |
| Family | Assimineidae | |
| Genus | Paludinella | |
| Authority | (Hanley in Thorpe, 1844) | |
| Recent Synonyms | Rissoa littorea Jeffreys, 1856Paludinella littorina (Delle Chiaje, 1828) sensu Philippi, 1841Cingula globularis Hanley in Thorpe, 1844 | |
Biology
| Typical abundance | Moderate density | ||
| Male size range | max. 2cm | ||
| Male size at maturity | No information | ||
| Female size range | max. 2cm | ||
| Female size at maturity | No information | ||
| Growth form | Globose | ||
| Growth rate | No information | ||
| Body flexibility | None (less than 10 degrees) | ||
| Mobility | Creeper | ||
| Characteristic feeding method | Sub-surface deposit feeder, Surface deposit feeder | ||
| Diet/food source | Detritivore | ||
| Typically feeds on | No information | ||
| Sociability | Gregarious | ||
| Environmental position | Epifaunal, Interstitial | ||
| Dependency | No information found. | ||
| Supports | No information | ||
| Is the species harmful? | No information | ||
Biology information
Very little data on biology found. The animal crawls by alternately extending the front and rear halves of the foot forward, producing a shuffling gait. The foot is short and rounded. It is found at low to moderate densities in narrow, linear habitats.
Habitat preferences
| Physiographic preferences | Isolated saline water (Lagoon), Open coast |
| Biological zone preferences | Lower littoral fringe, Supralittoral, Upper littoral fringe |
| Substratum / habitat preferences | Bedrock, Caves, Crevices / fissures, Gravel / shingle, Under boulders |
| Tidal strength preferences | Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.) |
| Wave exposure preferences | Sheltered |
| Salinity preferences | Variable (18-40 psu) |
| Depth range | Not relevant |
| Other preferences | No information |
| Migration Pattern |
Habitat Information
Paludinella globularis is probably under-recorded due to its small size, inaccessible habitat and the similarity of its shell to that of Littorina saxatilis. An update on the distribution of Paludinella globularis (as littorina) was compiled by Light & Killeen (2001). Frequent molluscan associates are the pulmonate Otina ovata in the crevice or cave habitat, and the pulmonates Ovatella myosotis and Leucophytia bidentata and prosobranch Truncatella subcylindrica in shingle interstices. Other species particularly associated with Paludinella gobularis are the Isopoda Ligia oceanica in cave habitats (unless Ligia oceanica is excessively dominant, then Paludinella globularis is excluded), and Bdella mites in the interstitial habitat of the upper shore shingle or boulders (Light & Killeen, 2001).Life history
Adult characteristics
| Reproductive type | No information | |
| Reproductive frequency | No information | |
| Fecundity (number of eggs) | No information | |
| Generation time | Insufficient information | |
| Age at maturity | No information | |
| Season | No information | |
| Life span | Insufficient information |
Larval characteristics
| Larval/propagule type | No information |
| Larval/juvenile development | No information |
| Duration of larval stage | No information |
| Larval dispersal potential | No information |
| Larval settlement period | No information |
Life history information
-none-Sensitivity review
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Physical pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| High | Low | High | Very low | |
Paludinella globularis would be removed upon substratum loss. Light & Killeen (1997) suggest that cliff instability may be the main threat to those colonies. Recoverability would be low because populations of the species are sparse. | ||||
| High | Low | High | Very low | |
Smothering could block shingle interstices, prevent movement of the snail and reduce the level of oxygenation. Recovery would be low because it probably lacks an aquatic dispersal phase and other colonies are distant. | ||||
| Intermediate | Moderate | Moderate | Very low | |
The species should be able to move through new silt and may be able to feed on it, so long as interstices remain clear. | ||||
| Intermediate | Low | High | Very low | |
Paludinella globularis is adapted to tolerate desiccation by its hard shell and operculum. However, the individuals that occur in crevices may not be able to tolerate twenty five percent increase in the time exposed to air. Those animals that are found in shingle will be largely sheltered from the effects of desiccation. | ||||
| Low | Moderate | Low | Very low | |
Increased or decreased emergence is likely to occur on a relatively long time scale during which the habitat and animals will probably be able to re-adjust. | ||||
| Low | Moderate | Low | Very low | |
Living at the high water mark, the species is inundated for only short periods so that increased water flow is unlikely to have a significant effect unless it is so great as to erode the substrate and wash animals away. | ||||
| Intermediate | Moderate | Moderate | Very low | |
The species reaches the northern limits of its distribution in England so may be particularly intolerant of reductions in temperature. The species would be protected from extremes in temperature where it lives in shingle or in crevices and caves. | ||||
| Tolerant | Not relevant | Not sensitive | Very low | |
The species will probably not be affected by a change in turbidity as it is not dependant on light availability. | ||||
| Intermediate | Low | High | Very low | |
Increased wave action may damage or wash away this species or move shingle, damaging the animal by abrasion. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| High | Very low / none | Very High | Low | |
Individuals living in caves and crevices are likely to be protected from physical disturbance. However, significantly increased pressure or trampling along high water mark at shingle sites could produce serious abrasion, which would damage the delicate shells. Therefore, intolerance has been assessed as high. Recovery would be low because populations are sparsely distributed. | ||||
| High | Low | High | Low | |
Habitat displacement would cause physical damage to animals. | ||||
Chemical pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| No information | Not relevant | No information | Not relevant | |
Observations following the Sea Empress oil spill off Pembrokeshire found that the populations of Paludinella globularis were not affected (Light & Killeen, 1997). However, prosobranchs usually are affected by hydrocarbons. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| Low | Low | Moderate | High | |
Paludinella globularis can tolerate a wide range of salinities as evidenced by its distribution in lagoons and on open shore. The species may not be able to withstand low salinity for long periods of time. | ||||
| No information | Not relevant | No information | Not relevant | |
| No information. | ||||
Biological pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| No information | Not relevant | No information | Not relevant | |
No information. | ||||
| Not relevant | Not relevant | Not relevant | Not relevant | |
Not relevant. | ||||
| High | Low | High | Very low | |
Could cause huge disturbance and damage but is unlikely. | ||||
Additional information
Importance review
Policy/legislation
| IUCN Red List | Least Concern (LC) |
Status
| National (GB) importance | Not rare/scarce | Global red list (IUCN) category | Least Concern (LC) |
Non-native
| Native | - | ||
| Origin | - | Date Arrived | - |
Importance information
-none-Bibliography
Datasets
Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2018-09-25.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-03-28
Citation
This review can be cited as:
Last Updated: 23/05/2000
