Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
Researched by | Angus Jackson | Refereed by | Dr Andrew C. Campbell |
Authority | (Östergren, 1898) Deichmann, 1944 | ||
Other common names | - | Synonyms | Pseudocucumis mixta (Östergren, 1898) Deichmann, 1944 |
Neopentadactyla mixta is a cylindrical sea cucumber up to about 20 cm long and creamy yellow in colour. The body tapers towards either end and there are a bunch of profusely branching tentacles around the mouth. The tentacles are usually light grey but may be darker, appearing almost transparent when fully extended. The gravel sea cucumber lives within the substratum so the only parts visible are the tentacles, when extended.
Various descriptions of the tentacles have been made regarding the layout and size of the rings. One of the most recent states that there are twenty in total arranged pentaradially around the mouth. There are ten large outer tentacles arranged as five pairs, then within these, five single intermediate tentacles and then the inside ring is of five small tentacles. Tube feet are usually confined to the radii and may be crowded in the middle of the body.
- none -
Phylum | Echinodermata | Starfish, brittlestars, sea urchins & sea cucumbers |
Class | Holothuroidea | Sea cucumbers |
Order | Dendrochirotida | |
Family | Phyllophoridae | |
Genus | Neopentadactyla | |
Authority | (Östergren, 1898) Deichmann, 1944 | |
Recent Synonyms | Pseudocucumis mixta (Östergren, 1898) Deichmann, 1944 |
Typical abundance | High density | ||
Male size range | Up to 25cm | ||
Male size at maturity | |||
Female size range | Medium-large(21-50cm) | ||
Female size at maturity | |||
Growth form | Cylindrical | ||
Growth rate | No information found | ||
Body flexibility | |||
Mobility | Burrower | ||
Characteristic feeding method | Passive suspension feeder | ||
Diet/food source | Omnivore | ||
Typically feeds on | Seston | ||
Sociability | Solitary | ||
Environmental position | Infaunal | ||
Dependency | No text entered. | ||
Supports | Host Melanella alba. | ||
Is the species harmful? | Data deficient |
Physiographic preferences | Open coast, Strait / sound, Sea loch / Sea lough, Ria / Voe |
Biological zone preferences | Lower infralittoral, Upper circalittoral |
Substratum / habitat preferences | Gravel / shingle, Maerl |
Tidal strength preferences | Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Weak < 1 knot (<0.5 m/sec.) |
Wave exposure preferences | Exposed, Moderately exposed, Sheltered, Very sheltered |
Salinity preferences | Full (30-40 psu) |
Depth range | 15-70 |
Other preferences | No text entered |
Migration Pattern | Diel, Seasonal (feeding) |
Reproductive type | No information | |
Reproductive frequency | No information | |
Fecundity (number of eggs) | No information | |
Generation time | Insufficient information | |
Age at maturity | No information found. | |
Season | Insufficient information | |
Life span | Insufficient information |
Larval/propagule type | - |
Larval/juvenile development | No information |
Duration of larval stage | No information |
Larval dispersal potential | No information |
Larval settlement period | Insufficient information |
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.
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
High | No information | High | Low | |
Neopentadactyla mixta lives within gravel or maerl substrata. Loss of this substrata would result in the loss of the population. | ||||
Low | No information | Moderate | Moderate | |
Although not a fast mover, Neopentadactyla mixta is a quite large active burrower. Smothering by five cm of sediment should not cause too many problems and the sea cucumber will probably be able to burrow back up to the surface. Individuals of this species spend much of the winter buried up to 60 cm deep in aerobic sediment. During this winter period, a torpid stage is entered with respiration and activity greatly reduced. Given sufficient aeration, this species can tolerate long periods without feeding. This may indicate that even if the surface cannot be regained immediately then the species could tolerate a period of smothering. There will be an energetic cost and feeding will be curtailed. Smothering for a month will be less problematic if it occurs during the period when the sea cucumbers are buried within the substratum. | ||||
High | No information | High | Low | |
A slight increase in siltation may benefit this species through greater availability of food particles. Larger increases in siltation will cause feeding to stop, the tentacles to be retracted and withdrawal into the substratum. Although the species can tolerate long periods (up to 8 months) without feeding within the substratum, considerable loss of condition occurs during this time. Prevention of feeding for a whole year through increased siltation will probably cause death. | ||||
No information | ||||
High | No information | High | Low | |
The species only occurs subtidally (below 15 m). The tube feet and tentacles provide surfaces through which water could easily be lost. Exposure to desiccating influences for an hour will probably cause death. | ||||
High | No information | High | Low | |
The species only occurs subtidally (below 15 m) and is not subject to emergence. Emergence for an hour will probably cause death. | ||||
No information | ||||
High | No information | High | Moderate | |
The gravel sea cucumber is a passive suspension feeder and requires a reasonable flow of water to provide sufficient food particles. The tentacular crown is held up in the water column in order to feed. Strong water flow causes the tentacles to be displaced and bent. This can only be tolerated up to a point and beyond that sea cucumber retracts its tentacles and withdraws into substratum. This would prevent feeding. Although the species can tolerate long periods (up to 8 months) without feeding within the substratum, considerable loss of condition occurs during this time. Prevention of feeding for a whole year will probably cause death. | ||||
No information | ||||
Intermediate | No information | High | Low | |
The British Isles falls in the middle of the geographic range of this species. Small chronic changes in temperature will probably have little effect. Short acute changes in temperature may cause death. Temperature changes will have less effect when the population is buried within the substratum and respiration and metabolism are greatly reduced. | ||||
No information | ||||
Tolerant | No information | Not sensitive | Low | |
The species has no requirement for photosynthesis and probably only has very limited facility for visual perception. Changes in turbidity will probably have no effect. | ||||
No information | ||||
High | No information | High | Moderate | |
The gravel sea cucumber is a passive suspension feeder and requires a reasonable water movement to provide sufficient food particles. The tentacular crown is held up in the water column in order to feed. Strong wave action causes the tentacles to be displaced and bent. This can only be tolerated up to a point and beyond that sea cucumber retracts its tentacles and withdraws into substratum. This would prevent feeding. Although the species can tolerate long periods (up to 8 months) without feeding within the substratum, considerable loss of condition occurs during this time. Prevention of feeding for a whole year will probably cause death. One large storm on the west coast of Ireland was noted to cause Neopentadactyla mixta to withdraw into the sediment and remain there for ten days (Smith and Keegan, 1984). | ||||
No information | ||||
Low | No information | Moderate | Moderate | |
Slight vibrations within the immediate substratum will provoke total withdrawal. This will prevent feeding. If the vibration is continuous, habituation may occur. If the noise occurs during the period of torpor then the species will be tolerant. | ||||
Tolerant | Not relevant | Not sensitive | High | |
The species probably only has very limited facility for visual perception. | ||||
Intermediate | No information | High | Low | |
The gravel sea cucumber is highly flexible and has a tough skin but the tentacles are more likely to be damaged by abrasion. Neopentadactyla mixta lives infaunally and hence may avoid physical disturbance caused by a passing dredge, particularly when deeply buried in a state of torpor. Echinoderms are well known for their regenerative abilities. However, no information regarding recruitment or recovery was found. | ||||
Tolerant | Not relevant | Not sensitive | Low | |
The species is an active burrower within the substratum. Displacement will probably have little effect and individuals would be able to re-burrow. |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
High | No information | High | Moderate | |
Hypo and hypersaline water causes tentacle retraction (Smith, 1983). Neopentadactyla mixta lives in fully saline conditions. Reductions in salinity would cause the sea cucumber to stop feeding. A short term reduction in salinity will probably not be serious, particularly if it occurs during a period of torpor within the substratum. Long term reductions in salinity are more problematic Although the species can tolerate long periods (up to 8 months) without feeding within the substratum, considerable loss of condition occurs during this time. Prevention of feeding for a whole year will probably cause death. | ||||
No information | ||||
Low | No information | Moderate | Moderate | |
The species can survive with very low oxygen consumption when buried in the substratum during periods of torpor |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
Not relevant | Not relevant | Not relevant | Low | |
It is highly unlikely that this species would be extracted for any reason. | ||||
Intermediate | No information | High | Moderate | |
Neopentadactyla mixta frequently lives in maerl beds. The algal nodules form a ideal, coarse, mobile substratum that the sea cucumber can burrow through. Maerl beds are exploited commercially. The effects of maerl removal may be less when the sea cucumber is in a state of torpor buried deep within the substratum. |
- no data -
National (GB) importance | - | Global red list (IUCN) category | - |
Native | - | ||
Origin | - | Date Arrived | - |
Hansen, B. & McKenzie, J.D., 1991. A taxonomic review of northern Atlantic species Thyonidiinae and Semperiellinae (Echinodermata: Holothuroidea: Dendrochirotida). Zoological Journal of the Linnean Society, 103, 101-127.
Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]
Keegan, B.F., 1974. The macro fauna of maerl substrates on the west coast of Ireland. Cahiers de Biologie Marine, XV, 513-530.
Konnecker, G. & Keegan, B.F., 1973. In situ behavioural studies on echinoderm aggregations. Helgolander Wissenschaftliche Meeresuntersuchungen, 24, 157-162.
Mortensen, T.H., 1927. Handbook of the echinoderms of the British Isles. London: Humphrey Milford, Oxford University Press.
Smith T.B. & Keegan, B.F., 1985. Seasonal torpor in Neopentadactyla mixta (Ostergren) (Holothuroidea: Dendrochirotida). In Echinodermata. Proceedings of the Fifth International Echinoderm Conference. Galway, 24-29 September 1984. (B.F. Keegan & B.D.S O'Connor, pp. 459-464. Rotterdam: A.A. Balkema.
Smith, T.B., 1983. Tentacular ultrastructure and feeding behaviour of Neopentadactyla mixta (Holothuroidea: Dendrochirota). Journal of the Marine Biological Association of the United Kingdom, 63, 301-311.
Smith, T.B., 1984. Ultrastructure and function of the proboscis in Melanella alba (Gastropoda: Eulimidae). Journal of the Marine Biological Association of the United Kingdom, 64, 503-512.
Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.
Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset:https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.
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: 2023-06-07
This review can be cited as:
Last Updated: 17/04/2008