A brachiopod (Novocrania anomala)

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Summary

Description

Brachiopods are bivalved animals unrelated to molluscs. Novocrania anomala looks rather like a limpet with a low conical shell or valve attached to a hard surface. The shell is oval in vertical view and up to 1.5 cm long. The other valve is cemented to the surface beneath the animal. The shell surface is smooth and has fine concentric lines. Shell colour is pale grey, yellow or white and is overlaid with a thin brown periostracum.

Recorded distribution in Britain and Ireland

From the Firth of Clyde up the west coast of Scotland including the Hebrides, Shetland, the south coast of England and the Isle of Man. In Ireland along the south coast, the north-west and the north-east.

Global distribution

From the Canary Isles, the Britain Isles, the Faeroe Isles, Norway, Iceland and Spitzbergen.

Habitat

Typically inhabits rocky current-swept bottoms in moderately shallow water. The species is not very tolerant of wave exposure and so is found in deep water or in sheltered fjordic sea lochs.

Depth range

15-1500

Identifying features

  • Ventral valve is cemented to substratum.
  • Dorsal valve conical with the apex posterior to the midpoint.
  • Valves lack articulation.
  • There is no pedicle.
  • Calcium carbonate based shell.

Additional information

Unusually for the inarticulate brachiopods, the shell contains calcium carbonate. In brachiopods the valves of the shell are dorso-ventral whereas in molluscs the valves are lateral.

Listed by

- none -

Biology review

Taxonomy

LevelScientific nameCommon name
PhylumBrachiopoda
ClassCraniata
OrderCraniida
FamilyCraniidae
GenusNovocrania
Authority(O. F. Müller, 1776)
Recent SynonymsCrania anomala (Müller, 1776)Neocrania anomala (Müller, 1776)

Biology

ParameterData
Typical abundanceModerate density
Male size range0.23 - 15mm
Male size at maturity
Female size rangeSmall(1-2cm)
Female size at maturity
Growth formBivalved
Growth rateData deficient
Body flexibilityNo information
MobilitySessile, permanent attachment
Characteristic feeding methodActive suspension feeder
Diet/food sourcePlanktotroph
Typically feeds onseston
SociabilityNo information
Environmental positionEpifaunal
DependencyNo information found.
SupportsNo information found
Is the species harmful?No

No text entered

Biology information

The lophophore forms the main feeding organ. Mucus is not used in particle capture, only for transport. Novocrania anomala exhibits some degree of particle selectivity. There is a complex mechanism for particle rejection. There is little information on growth rate except that it is believed to be represented by an exponentially declining curve but dependent on depth, food, population density etc. Growth after the first year is slow. Four or five year classes can be identified. Novocrania anomala is capable of recovery from considerable damage to the shell and soft tissue. The adults can be maintained quite well in aquaria and are generally hardy organisms.

Habitat preferences

ParameterData
Physiographic preferencesOpen coast, Offshore seabed, Sea loch or Sea lough, Open coast, Offshore seabed, Sea loch or Sea lough
Biological zone preferencesLower circalittoral, Lower infralittoral, Upper circalittoral, Lower circalittoral, Lower infralittoral, Upper circalittoral
Substratum / habitat preferencesBedrock, Large to very large boulders, Other species, Small boulders, Bedrock, Large to very large boulders, Other species, Small boulders
Tidal strength preferencesModerately strong 1 to 3 knots (0.5-1.5 m/sec.), Very weak (negligible), Weak < 1 knot (<0.5 m/sec.), Moderately strong 1 to 3 knots (0.5-1.5 m/sec.), Very weak (negligible), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesExtremely sheltered, Moderately exposed, Sheltered, Ultra sheltered, Very sheltered, Extremely sheltered, Moderately exposed, Sheltered, Ultra sheltered, Very sheltered
Salinity preferencesFull (30-40 psu), Full (30-40 psu)
Depth range15-1500
Other preferencesNo text entered
Migration PatternNon-migratory or resident

Habitat Information

Absent from the Irish Sea and from the east coast of Britain. Can often be found living on Modiolus sp. or empty scallop shells.

Life history

Adult characteristics

ParameterData
Reproductive typeGonochoristic (dioecious)
Reproductive frequency Annual protracted
Fecundity (number of eggs)No information
Generation timeInsufficient information
Age at maturityData deficient.
SeasonApril - November
Life span5-10 years

Larval characteristics

ParameterData
Larval/propagule type-
Larval/juvenile development Lecithotrophic
Duration of larval stage2-10 days
Larval dispersal potential 100 -1000 m
Larval settlement periodInsufficient information

Life history information

Longevity is suspected to be between 8-10 years. There is no obvious sexual dimorphism although the colour of the gonads may be distinguishing. Testes are light coloured white, pink, cream or blue and ovaries are orange-brown. Egg diameter is 120-125 microns. The species is free-spawning and fertilisation is external in the surrounding water column. The eggs are more dense than seawater and hatch into a free-swimming larval stage. The larvae are fully developed within three days and settle out in no more than a few days. Most of the literature suggests that dispersal ability is not great. Although the species may inhabit areas with water flow rates of up to 3 knots, the often restricted and sheltered habitat such as sea lochs may reduce dispersal ability. The breeding season in western Scotland has been inferred from the presence of recently settled juveniles. The larva may be able to delay settlement if the initial substratum is unsuitable or the water is too deep.

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

Use / to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Substratum loss [Show more]

Substratum loss

Benchmark. All of the substratum occupied by the species or biotope under consideration is removed. A single event is assumed for sensitivity assessment. Once the activity or event has stopped (or between regular events) suitable substratum remains or is deposited. Species or community recovery assumes that the substratum within the habitat preferences of the original species or community is present. Further details

Evidence

The adults are permanently cemented to the substratum so substratum loss would result in the death of the population. Adults are permanently attached to the substratum so no adult immigration is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). Reproduction occurs annually and over an extended period of time.
High Moderate Moderate Low
Smothering [Show more]

Smothering

Benchmark. All of the population of a species or an area of a biotope is smothered by sediment to a depth of 5 cm above the substratum for one month. Impermeable materials, such as concrete, oil, or tar, are likely to have a greater effect. Further details.

Evidence

The dorsal valve of the shell can be clamped down and low oxygen concentrations can be tolerated for a few days. However smothering by sediment for a month will prevent feeding and restrict oxygen concentrations for considerably longer and will probably cause death. Adults are permanently attached to the substratum so no adult immigration is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). Reproduction occurs annually and over an extended period of time.
High Moderate Moderate Moderate
Increase in suspended sediment [Show more]

Increase in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

Neocrania anomala has a complex mechanism for removing unwanted particulate material brought in with the inhalant water current. Increases in siltation rate will result in a more regular requirement for this material to be removed. This will have an energetic cost and interfere with feeding. On removal of the factor it may take some time for the animals to regain condition.
Low Very high Very Low Moderate
Decrease in suspended sediment [Show more]

Decrease in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

No information
Desiccation [Show more]

Desiccation

  1. A normally subtidal, demersal or pelagic species including intertidal migratory or under-boulder species is continuously exposed to air and sunshine for one hour.
  2. A normally intertidal species or community is exposed to a change in desiccation equivalent to a change in position of one vertical biological zone on the shore, e.g., from upper eulittoral to the mid eulittoral or from sublittoral fringe to lower eulittoral for a period of one year. Further details.

Evidence

The species tends to be attached to hard substrata at depths of at least 15 metres. It is extremely unlikely that the population would be exposed to desiccation.
Not relevant Not relevant Not relevant Moderate
Increase in emergence regime [Show more]

Increase in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

The species tends to be attached to hard substrata at depths of at least 15 metres. It is extremely unlikely that the population would be exposed to an emergence regime.
Not relevant Not relevant Not relevant Moderate
Decrease in emergence regime [Show more]

Decrease in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

No information
Increase in water flow rate [Show more]

Increase in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

The species is found in waters with a maximum velocity of 2-3 knots. Increases above this level would probably cause death. Decreases in water flow rate are unlikely to have any effect as feeding currents are generated by the animal itself. Adults are permanently attached to the substratum so no adult immigration is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). Reproduction occurs annually and over an extended period of time.
High Moderate Moderate Moderate
Decrease in water flow rate [Show more]

Decrease in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

No information
Increase in temperature [Show more]

Increase in temperature

  1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
  2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

The geographic distribution of Neocrania anomala extends to the north and south of the British Isles and so is exposed to higher and lower water temperatures. Small, long term changes in temperature are unlikely to have much effect. Short acute changes, particularly increases may cause death. Adults are permanently attached to the substratum so no adult immigration to supplement the population is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). The species may live for up to ten years. Reproduction occurs annually and over an extended period of time.
Intermediate High Low
Decrease in temperature [Show more]

Decrease in temperature

  1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
  2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

No information
Increase in turbidity [Show more]

Increase in turbidity

  1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
  2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

The species has no reliance on light availability. It is found at up to 1500 metres in depth where light availability is virtually nil. Changes in light transmission and attenuation are unlikely to affect this species.
Tolerant Not relevant Not sensitive Low
Decrease in turbidity [Show more]

Decrease in turbidity

  1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
  2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

No information
Increase in wave exposure [Show more]

Increase in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

This species is not very tolerant of wave exposure being generally found in sheltered locations like fjords and sea lochs or in deeper water. Increases in wave exposure above moderately exposed would probably cause death. Adults are permanently attached to the substratum so no adult immigration is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). Reproduction occurs annually and over an extended period of time.
High Moderate Moderate Moderate
Decrease in wave exposure [Show more]

Decrease in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

No information
Noise [Show more]

Noise

  1. Underwater noise levels e.g., the regular passing of a 30-metre trawler at 100 metres or a working cutter-suction transfer dredge at 100 metres for one month during important feeding or breeding periods.
  2. Atmospheric noise levels e.g., the regular passing of a Boeing 737 passenger jet 300 metres overhead for one month during important feeding or breeding periods. Further details

Evidence

The species probably has limited facility for detection of noise vibrations. Local noise may cause the animal to close its valves.
Low Very high Very Low Low
Visual presence [Show more]

Visual presence

Benchmark. The continuous presence for one month of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans) within the visual envelope of the species or community under consideration. Further details

Evidence

Although the species does not have eyes or pigment spots, there is a mechanism for visual detection and a highly developed 'shadow reflex' in response to moving objects where the dorsal valve snaps shut. How this is of use in deep water with very low light levels is uncertain. On removal of the factor it may take some time for the animals to regain condition.
Low Very high Very Low Moderate
Abrasion & physical disturbance [Show more]

Abrasion & physical disturbance

Benchmark. Force equivalent to a standard scallop dredge landing on or being dragged across the organism. A single event is assumed for assessment. This factor includes mechanical interference, crushing, physical blows against, or rubbing and erosion of the organism or habitat of interest. Where trampling is relevant, the evidence and trampling intensity will be reported in the rationale. Further details.

Evidence

Although the animal is protected by a calcified shell, it is not massively strong and physical disturbance due to a passing scallop dredge will probably cause damage and death. Adults are permanently attached to the substratum so no adult immigration to supplement the population is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). The species may live for up to ten years. Reproduction occurs annually and over an extended period of time (Long & Stricker, 1991; James et al., 1992).
Intermediate High Low Moderate
Displacement [Show more]

Displacement

Benchmark. Removal of the organism from the substratum and displacement from its original position onto a suitable substratum. A single event is assumed for assessment. Further details

Evidence

Neocrania anomala is permanently attached to the substratum. If removed, the attachment cannot be reformed. Once detached, the brachiopod can then be moved around by water currents into unsuitable orientations or habitat and will probably cause death. Adults are permanently attached to the substratum so no adult immigration is possible. No information is available about fecundity. Dispersal ability is not considered to be that great although in many locations there are nearby populations (particularly the west coast of Scotland). Reproduction occurs annually and over an extended period of time.
High Moderate Moderate Moderate

Chemical pressures

Use [show more] / [show less] to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Synthetic compound contamination [Show more]

Synthetic compound contamination

Sensitivity is assessed against the available evidence for the effects of contaminants on the species (or closely related species at low confidence) or community of interest. For example:

  • evidence of mass mortality of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as high sensitivity;
  • evidence of reduced abundance, or extent of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as intermediate sensitivity;
  • evidence of sub-lethal effects or reduced reproductive potential of a population of the species or community of interest will be assessed as low sensitivity.

The evidence used is stated in the rationale. Where the assessment can be based on a known activity then this is stated. The tolerance to contaminants of species of interest will be included in the rationale when available; together with relevant supporting material. Further details.

Evidence

Insufficient
information
No information No information No information Not relevant
Heavy metal contamination [Show more]

Heavy metal contamination

Evidence

Insufficient
information
No information No information No information Not relevant
Hydrocarbon contamination [Show more]

Hydrocarbon contamination

Evidence

Insufficient
information
No information No information No information Not relevant
Radionuclide contamination [Show more]

Radionuclide contamination

Evidence

Insufficient
information
No information No information No information Not relevant
Changes in nutrient levels [Show more]

Changes in nutrient levels

Evidence

Insufficient
information
No information No information No information Not relevant
Increase in salinity [Show more]

Increase in salinity

  1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
  2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

Neocrania anomala is found in a variety of salinity conditions ranging from full down through variable and reduced to low (Connor et al., 1997a.)
Tolerant Not relevant Not sensitive High
Decrease in salinity [Show more]

Decrease in salinity

  1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
  2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

No information
Changes in oxygenation [Show more]

Changes in oxygenation

Benchmark.  Exposure to a dissolved oxygen concentration of 2 mg/l for one week. Further details.

Evidence

Brachiopods generally have low metabolic rates with oxygen consumption being about half that of a similar sized bivalve mollusc. They can sustain anaerobic metabolism for 3-5 days. The articulate brachiopod Terebratulina unguicula is found in conditions where oxygen concentrations are frequently below 0.1 mg/l. At low oxygen concentrations activity may be reduced. On removal of the factor it may take some time for the animals to regain condition.
Low Very high Very Low High

Biological pressures

Use [show more] / [show less] to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Introduction of microbial pathogens/parasites [Show more]

Introduction of microbial pathogens/parasites

Benchmark. Sensitivity can only be assessed relative to a known, named disease, likely to cause partial loss of a species population or community. Further details.

Evidence

Insufficient
information
No information No information No information Not relevant
Introduction of non-native species [Show more]

Introduction of non-native species

Sensitivity assessed against the likely effect of the introduction of alien or non-native species in Britain or Ireland. Further details.

Evidence

Insufficient
information
No information No information No information Not relevant
Extraction of this species [Show more]

Extraction of this species

Benchmark. Extraction removes 50% of the species or community from the area under consideration. Sensitivity will be assessed as 'intermediate'. The habitat remains intact or recovers rapidly. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

It is extremely unlikely that this species will be subject to targeted extraction.
Not relevant Not relevant Not relevant Low
Extraction of other species [Show more]

Extraction of other species

Benchmark. A species that is a required host or prey for the species under consideration (and assuming that no alternative host exists) or a keystone species in a biotope is removed. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

Neocrania anomala has no known obligate relationships.
Tolerant Not relevant Not sensitive Low

Additional information

Importance review

Policy/legislation

- no data -

Status

Non-native

ParameterData
Native-
Origin-
Date Arrived-

Importance information

Novocrania anomala may be a dominant component of species assemblages in which it is found. Novocrania anomala may be preyed upon by starfish, crustacea, gastropods and fish. The shells of brachiopods are easily drilled into, in comparison to molluscs, and the shells of Novocrania anomala are often heavily bored. However, predation levels are apparently low, possibly because of a low energy yield or because it is an unpalatable species.

Bibliography

  1. Atkins, D. & Rudwick, M.J.S., 1962. The lophophore and ciliary feeding mechanisms of the brachiopod Crania anomala (Müller). Journal of the Marine Biological Association of the United Kingdom, 42, 469-480.

  2. Brunton, C.H.C. & Curry, G.B., 1979. British Brachiopods. London: Academic Press. [Synopses of the British Fauna, no. 17.]

  3. Connor, D.W., Dalkin, M.J., Hill, T.O., Holt, R.H.F. & Sanderson, W.G., 1997a. Marine biotope classification for Britain and Ireland. Vol. 2. Sublittoral biotopes. Joint Nature Conservation Committee, Peterborough, JNCC Report no. 230, Version 97.06., Joint Nature Conservation Committee, Peterborough, JNCC Report no. 230, Version 97.06.

  4. Harper, D.A.T., 1991. The brachiopods Neocrania and Terebratulina from Galway Bay. Irish Naturalists' Journal, 23, 371-376.

  5. 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.]

  6. James, M.A., Ansell, A.D., Collins, M.J., Curry, G.B., Peck, L.S. & Rhoda, M.C., 1992. Biology of living brachiopods. Advances in Marine Biology, 28, 175-387.

  7. Long, J.A. & Stricker, S.A., 1991. Brachiopoda. In Reproduction of marine invertebrates, Vol. VI. Echinoderms and Lophophorates. (ed. A.C. Giese, J.S. Pearse & V.B. Pearse). California: The Boxwood Press.

  8. Rowell, A.J., 1960. Some early stages in the development of the brachiopod Crania anomala (Müller). Annals and Magazine of the Natural History Society, 13th Series, 3, 35-52.

  9. Rudwick, M.J.S., 1970. Living and fossil brachiopods. London: Hutchinson University Library

Datasets

  1. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-06-15

Citation

This review can be cited as:

Jackson, A. 2000. Novocrania anomala A brachiopod. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 15-06-2024]. Available from: https://www.marlin.ac.uk/species/detail/1331

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Last Updated: 19/04/2000