Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Petricolaria pholadiformis
(false angel wing)



Petricolaria pholadiformis (false angel wing)


  • Last modified
  • 19 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Petricolaria pholadiformis
  • Preferred Common Name
  • false angel wing
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Mollusca
  •       Class: Bivalvia
  •         Subclass: Heterodonta
  • Summary of Invasiveness
  • P. pholadiformis is a boring bivalve that lives in the shallow waters of coastal areas. Outside its native range, it has established viable populations in most areas that have been invaded. Its introduction has b...

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External view of Petricolaria pholadiformis shells
TitleExternal view
CaptionExternal view of Petricolaria pholadiformis shells
CopyrightStratos Xentidis
External view of Petricolaria pholadiformis shells
External viewExternal view of Petricolaria pholadiformis shellsStratos Xentidis


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Preferred Scientific Name

  • Petricolaria pholadiformis (Lamarck, 1818)

Preferred Common Name

  • false angel wing

Other Scientific Names

  • Gastanella tumida Verril, 1872
  • Petricola lata Dall, 1925
  • Petricola pholadiformis Lamarck, 1818

International Common Names

  • English: American piddock
  • Spanish: falso ala de ange
  • French: fausse aile d' ange; petricole d' Amérique; petricole pholadiforme

Local Common Names

  • Denmark: Amerikansk boremusling
  • Germany: Amerikanische bohrmuschel; Engelsflügel
  • Netherlands: Amerikaanse boormossel
  • Norway: Amerikansk boreskjell
  • Sweden: Amerikansk bormussla

Summary of Invasiveness

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P. pholadiformis is a boring bivalve that lives in the shallow waters of coastal areas. Outside its native range, it has established viable populations in most areas that have been invaded. Its introduction has been attributed to its accidental presence in oyster shipments coming to Europe from the USA for aquaculture purposes, but also to shipping and natural dispersal. It appears that reduced salinity facilitates its establishment (Zenetos et al., 2009). Although P. pholadiformis is present in the North Sea for more than a hundred years, its expansion and distribution are relatively limited. It was first reported as an invasive species in the Netherlands and Belgium where it outcompeted a native boring bivalve species Barnea candida, although no such effect has been documented in other countries (Budd, 2005).

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Mollusca
  •             Class: Bivalvia
  •                 Subclass: Heterodonta
  •                     Order: Veneroida
  •                         Unknown: Veneroidea
  •                             Family: Petricolidae
  •                                 Genus: Petricola
  •                                     Species: Petricolaria pholadiformis

Notes on Taxonomy and Nomenclature

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Petricola pholadiformis belongs to the genus Petricola Lamarck, 1801, of the family Petricolidae Deshayes, 1831, which belongs to the superfamily Veneroidea Rafinesque, 1815. There are five genera in the family Petricolidae: Choristodon, Cooperella, Mysia, Petricola, and Rupellaria. Members of the genus Petricola include Petricolacaliforniensis Pilsbry and Lowe, 1932; Petricola carditoides (Conrad, 1837); Petricola hertzana Coan, 1997; Petricola lapicida (Gmelin, 1791); Petricola lithophaga (Retzius, 1786); Petricola lucasana Herlein and Strong, 1948.

However, for the purposes of this datasheet the name Petricolaria pholadiformis with be used, with Petricola pholadiformis placed as a synonym, as in agreement with the World Register of Marine Species (


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Adult P. pholadiformis have a thin fragile shell with an elongate oval outline and cylindrical shape, which is similar in sculpture on both sides. The anterior end is short and rounded, and the posterior is elongated and slightly gaping. There is a well defined lunule in the front, whereas the beaks (tips) of each valve are in the anterior half, and turn downward and inwards. Both valves have clearly visible teeth.

The outside surface of the shell is covered with strong ribs (>40) radiating from the top, that cross numerous and distinct concentric growth lines. Ribs at the anterior end are large, coarse, widely spaced and elevated. These squamous projections are used by the animal to ‘bore’ through the substrate. Ribs at the posterior end are crowded and faint. The inside of the shell is smooth and white in colour. The ligament is external and prominent, stretching a quarter of the way between the beaks to the posterior margin.

The colour of the shell ranges from off-white to dirty cream yellow. Lime white, fawn and yellowish white are the most usual shell colourations, and the periostracum is dark brown. Older specimens are coloured brownish yellow.

The length of the shell ranges from 25-80 mm, but specimens are commonly up to 65 mm long.

Larvae of this species have a total length of 60-185 µm. The straight-hinge stage ends at ~105 µm length, at which time a broadly rounded umbo develops. The anterior end is slightly longer than posterior, the ends of the shell are nearly equally rounded, and the shoulders are straight and slope steeply. There is no distinctive color, though the margin is dark. The eye spot is not pigmented and the shell is heavier than in most clams. Metamorphosis occurs at ~175 µm (Chanley and Andrews, 1971).

To summarize, the key identification features of this species are:
- Shell is thin, brittle, equivalve, inequilateral, elongate and oval in outline.
- Beaks in anterior half are turned downwards and inwards, sometimes set back from the dorsal edge.
- Colour of the shell is off-white or fawn, with a dark brown periostracum.
- Interior of the shell white, with the coarse anterior ribs showing through.
- Prominent ligament.
- Sculpturing of concentric rings is crossed anteriorly by about 40 ribs that are spined at the anterior end.
- Anterior margin of shell crenulates where the large ribs meet it, while it is smooth elsewhere (Budd, 2005).


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The false angel wing P. pholadiformis originates from the western Atlantic, where it is present from the Gulf of St Lawrence to Uruguay (Abbott, 1974). In Great Britain, it is present along the south and west English coasts (Davison, 1996), from Lyme Regis, in Dorset, to the Humber. It is most common off the coast of Essex (River Crouch) (JNCC, 2009) and the Thames Estuary (River Medway). There are also isolated records from north Wales and Cornwall (Budd, 2005). It is not present in Scotland (Davison, 1996).

In the Netherlands it is present along the entire coastline, is locally very abundant, and is one of the most common species of the Dutch coast (Wolff, 2005). In Denmark, P. pholadiformis was first reported in 1905 from the Wadden Sea, and is presently established in the Wadden Sea, along the Skagerrak coast, the Limfjord, and in the northern Kattegat (Jensen and Knudsen, 2005).

The first record of P. pholadiformis from the Mediterranean Sea was in the Saronikos Gulf (southern Aegean Sea), Greece (Zenetos et al., 2009).

A record of this species from the western Mediterranean (Spain and Tunisia) (Poutiers, 1987), was not substantiated by literature, and was therefore disputed (Zenetos et al., 2004). According to local experts, the species is absent from both areas. However, the species was recently detected in the Nervión estuary, Spain, (southeastern Bay of Biscay) (Zorita et al., 2013), It is also reported as established in France (North Sea) (Müller, 2004; Dewarumez, 2011).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Sea Areas

Atlantic, NortheastWidespreadIntroduced<1890 Invasive Naylor, 1957
Atlantic, NorthwestPresentNative Not invasive Harvey-Clark, 1997
Atlantic, Western CentralPresentNative Not invasive Hill et al., 2005
Mediterranean and Black SeaPresent, few occurrencesIntroduced1985Zenetos et al., 2004Saronikos Gulf
Pacific, Eastern CentralPresentIntroduced1927Ray, 2005Newport Bay, San Francisco Bay, Willapa Bay


TunisiaAbsent, unreliable recordIntroducedPoutiers, 1987

North America

CanadaPresentNative Not invasive Harvey-Clark, 1997
MexicoPresentNative Not invasive Hill et al., 2005
USAPresentNative Not invasive Hill et al., 2005
-CaliforniaPresentIntroduced1927Ray, 2005
-WashingtonPresentIntroduced1943Cohen et al., 2001


BelgiumPresentIntroduced1899 Invasive Loppens, 1905unintentionally released
DenmarkPresentIntroduced1896Bagge, 1968naturalized
FranceLocalisedIntroduced1992Dewarumez et al., 2011
GermanyPresentIntroduced1896Schlesch, 1932In the Baltic Sea since 1927: unintentional-release from oyster farms (Schlesch 1932). In the North Sea
GreecePresent, few occurrencesIntroduced1985Zenetos et al., 2009
NetherlandsPresentIntroduced1899 Invasive Denker, 1907
NorwayPresentIntroduced1953Rustad, 1955accidental
SpainPresentIntroduced2007Zorita et al., 2013
SwedenPresentIntroduced1944 Invasive Hessland, 1944established
UKPresentIntroduced<1890Naylor, 1957naturalized

History of Introduction and Spread

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P. pholadiformis was introduced accidentally into the United Kingdom, in shipments of the American oyster Crassostrea virginica, sometime before 1890 (Eno et al., 1997). It was subsequently reported from Germany (1896) (NOBANIS, 2009) and the Wadden Sea, Denmark (1905) (Jensen and Knudsen, 2005). The species became common in Kattegat from where it spread to the coasts of Belgium (1899) and the Netherlands (1905) (ICES, 1972; Wolff, 2005). It is unknown how it spread from the British Isles to the shores of continental Europe, although expansion of the larval stage with marine currents is the most likely reason. Rosenthal (1980) suggested that P. pholadiformis may also have spread via driftwood. It was later reported from Norway (1955), and Sweden (NOBANIS, 2009).

During or before 1927, it was found in San Francisco Bay on the Pacific coast of North America and subsequently in Willapa Bay (1947), and Newport Bay (1972) (Ray, 2005). The most likely vector in these instances is oyster shipments, although ballast-water is a possibility (Cohen and Carlton, 1995).
In the Mediterranean Sea, it was first reported in 1985 in the Gulf of Saronikos (Greece), and its occurrence in the area is probably shipping related (Zenetos et al., 2009). The possibility of spreading by means of its pelagic larvae should be ruled out, because of its absence from the western Mediterranean Sea (Zenetos et al., 2009).



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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Belgium 1899 Breeding and propagation (pathway cause) Yes Loppens (1905) Unintentional
California 1927 Aquaculture (pathway cause) Yes Ray (2005) Unintentional
Denmark 1905 Breeding and propagation (pathway cause) Yes Bagge (1968) Unintentional
Germany 1896 Breeding and propagation (pathway cause) Yes Schlesch (1932) Unintentional
Greece 1985 Yes Zenetos et al. (2009) Unintentional, from the Atlantic
Netherlands  1905 Breeding and propagation (pathway cause) Yes Denker (1907) Unintentional
Norway 1955 Breeding and propagation (pathway cause) Yes Rustad (1955) Unintentional
Sweden 1905 Breeding and propagation (pathway cause)Hessland (1944) Unintentional
UK USA <1890 Aquaculture (pathway cause) Yes Naylor (1957) Unintentional

Risk of Introduction

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In the North Sea, the history of the expansion of P. pholadiformis shows that although it has been established for a significant period of time in some areas, it has failed to colonize nearby shores. A good example of this is its absence from the Scottish coast, despite its presence on the English coast for more than a century (Davison, 1996). Similarly, the fact that P. pholadiformis has been present in the west Baltic Sea since the 1950s but has not yet expanded eastwards, shows that it is not exhibiting an invasive behaviour. Furthermore, the tightening of legislation concerning oyster shipments and other items associated with aquaculture, including a recent European Council Directive (2006/88/EC) on this issue, is another factor that forces a certain limitation to its being accidentally imported to new areas. However, P. pholadiformis is mentioned as a “potential next pest” for Australia by Hayes and Sliwa (2003). It can therefore be assumed that this species has a low possibility for further spread outside its present range.


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P. pholadiformis is a mechanical borer, and is unable to live on open surfaces, requiring a hard substratum (hard clay, chalk, solid mud, peat, wood or limestone) to bore into, while it breathes and filters food through two long siphons (Budd, 2005; Zenetos et al., 2009). It is only found in fine sediments with a median grain size of < 250 µm. In sediments with a median grain size of 100-150 µm a relative occurrence of 50% is even noted. The mud content seems less decisive for the habitat preference. However, the species does not occur in sediments without mud and the relative occurrence increases as the mud content of the sediment increases (ERMS, 2009).
P. pholadiformis occurs in ports and lagoons, and is generally found in shallow waters from the lower intertidal zone down to 8 m (Zenetos et al., 2004). However, the maximum water depth for this species is not known (Zenetos et al., 2009). At all sites where P. pholadiformis has been found there is some freshwater inflow into the sea (Zenetos et al., 2009).

As the animal becomes older, it bores deeper into the substratum. According to the literature, the species in its native range inhabits environments with salinities between 29 and 35 ppt, while in the Baltic Sea it is reported from salinities 10-30 ppt (Gollasch and Mecke, 1996). According to Castagna and Chanley (1973), the lower salinity tolerance of P. pholadiformis is 7.5-10 ppt.

Habitat List

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Coastal areas Principal habitat
Estuaries Principal habitat
Lagoons Principal habitat
Inshore marine Principal habitat
Benthic zone Principal habitat

Biology and Ecology

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Please see Espiñeira et al. (2009) for more on the genetics of this species.


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Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)

Water Tolerances

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ParameterMinimum ValueMaximum ValueTypical ValueStatusLife StageNotes
Salinity (part per thousand) 29 35 Optimum 7.5-35 tolerated (Castagna and Chanley, 1973)

Means of Movement and Dispersal

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Natural Dispersal
After its initial introduction to the UK, P. pholadiformis spread from the British Isles to the shores of continental Europe via expansion of the larval stage with marine currents (Rosenthal, 1980). The same author suggests that adults of this species may also have spread via floating vegetation (i.e. driftwood).
Accidental Introduction
The initial introduction of P. pholadiformis in Europe (UK) was due to Crassostrea gigas oyster shipments, arriving from the Atlantic coast of the United States for aquaculture purposes (Eno et al., 1997). This species was also accidentally introduced, most likely in the same way, in San Fransisco Bay, in the Pacific coast of the United States (Cohen and Carlton, 1995). However, there is a possibility that its introduction in that area was due to shipping (Cohen and Carlton, 1995; Cohen, 1998), as is the case for its introduction to Greece in the Mediterranean Sea (Zenetos et al., 2005).
Intentional Introduction

There is no record of this species being intentionally introduced in any area.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Aquaculture Yes Yes Naylor, 1957
Breeding and propagation Yes Yes Rosenthal, 1980
Hitchhiker Yes Yes Rosenthal, 1980

Pathway Vectors

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Impact Summary

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Environment (generally) Negative

Environmental Impact

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P. pholadiformis may displace native species of boring bivalves. This has happened in Belgium and the Netherlands, where it has almost completely replaced the indigenous white piddock (Barnea candida) (ICES, 1972; Cohen and Carlton, 1995). In Britain, however, where this species is also common, there is no documentary evidence for its having displaced, or outcompeted native piddocks (Budd, 2005; JNCC, 2009).

P. pholadiformis bores into clay, peat, mud, sand and other soft sediments, and may therefore modify habitats (Cohen and Carlton, 1995).This burrowing creates a generally uneven surface on a small scale (5-15 cm) providing habitats for other animals that inhabit vacant burrows and crevices in the clay (Marshall, 2008).

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Barnea candidaNo details No detailsBelgium; NetherlandsCompetitionICES, 1972

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Long lived
Impact outcomes
  • Conflict
  • Ecosystem change/ habitat alteration
  • Modification of natural benthic communities
  • Reduced native biodiversity
  • Threat to/ loss of native species
Impact mechanisms
  • Fouling
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally

Similarities to Other Species/Conditions

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P. pholadiformis (false angel wing) is very similar to the real angel wing (Crytopleura costata). The major way to tell them apart is by the presence of the apophysis (a spoon-like projection located below the beak of Crytopleuracostata) that P. pholadiformis lacks. The Campeche angel wing (Pholas campechiensis) is also similar to this species, but the presence of a twelve-partitioned brace that curves up over on the hinge side of the shell, distinguishes it from P. pholadiformis that does not have such a feature.

P. pholadiformis may be confused with white piddock (Barnea candida), a native species in several countries, including Denmark, Sweden, Germany, the Netherlands and Britain. P. pholadiformis bears a superficial resemblance to Barnea candida, but has 2 cardinal teeth in the right valve and 3 in the left valve where Barnea candida has none (Tebble, 1966; Budd, 2005). P. pholadiformis may also be confused with the oval piddock (Zirphaea crispata), which can be distinguished by a conspicuous groove in each valve of its shell and a large gape where its foot protrudes.

Gaps in Knowledge/Research Needs

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Unfortunately, there is very little actual data on most aspects of the biology and ecology of the false angel wing P. pholadiformis.


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Abbott R, 1974. American Seashells. New York, : Van Nostrand Reinhold, 663 pp.

Bagge O, 1968. Faunaforurening. In: Danmarks Natur [ed. by Nørrevang A, Meyer TJ]: Politiken, 483-485.

Budd GC, 2005. Petricola pholadiformis. American piddock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom.

Castagna M; Chanley P, 1973. Salinity tolerance of some marine bivalves from inshore and estuarine environments in Virginia waters on the western mid-Atlantic coast. Malacologia, 12:47-96.

Chanley P; Andrews JD, 1971. Aids for identification of bivalve larvae of Virginia. Malacologia, 11(1):45-119.

Cohen AN, 1998. Ships' Ballast Water and the Introduction of Exotic Organisms into the San Francisco Estuary: Current Status of the Problem and Options for Management. Richmond CA, : San Francisco Estuary Institute.

Cohen AN; Berry HD; Mills CE; Milne D; Britton-Simmons K; Wonham MJ; Secord DL; Barkas JA; Bingham B; Bookheim BE; Byers JE; Chapman JW; Cordell JR; Dumbauld B; Fukuyama A; Harris LH; Kohn AJ; Li K; Mumford TF; Radashevsky V; Sewell AT; Welch K, 2001. A rapid survey of exotic species in the shallow waters of Elliott Bay, Totten and Eld Inlets, and Willapa Bay. WSEE 2000. Report prepared for the Nearshore Habitat Program, Washington State Department of Natural Resources., 1-52 pp.

Cohen AN; Carlton JT, 1995. Biological Study. Nonindigenous Aquatic Species in a United States Estuary: A Case Study of the Biological Invasions of the San Francisco Bay and Delta. A Report for the United States Fish and Wildlife Service, Washington DC, and The National Sea Grant College Program, Connecticut Sea Grant, NTIS Report Number PB96-166525., 701.

DAISIE, 2009. Delivering Alien Invasive Species Inventories for Europe.

Davison DM, 1996. An estimation of the total number of marine species that occur in Scottish coastal waters. Scottish Natural Heritage Review, No 63.

Delamotte M; Vardala-Theodorou E, 1994. Shells from the Greek seas. Athens, : The Goulandris National History Museum, 313 pp.

Denker C, 1907. [English title not available]. (Een nieuw schelpdier voor onze fauna) De Levende Natuur, 12:215.

Dewarumez JM; Gevaert F; Massé C; Foveau A; Desroy N; Grulois D, 2011. [English title not available]. Les espèces marines animales et végétales introduites dans le bassin Artois-Picardie. UMR CNRS 8187 LOG et Agence de l'Eau Artois-Picardie, 140 pp.

Duval DM, 1963. The biology of Petricola pholadiformis Lamarck (Lammellibranchiata: Petricolidae). Proceedings of the Malacological Society, 35:89-100.

Eno NC; Clark RA; Sanderson WG, 1997. Non-native marine species in British waters: a review and directory. UK: Joint Nature Conservation Committee, 152.

ERMS, 2009. The European Register of Marine Species. MarBEF Data System.

Espiñeira M; González-Lavín N; Vieites JM; Santaclara FJ, 2009. Development of a method for the genetic identification of commercial bivalve species based on mitochondrial 18S rRNA sequences. Journal of Agricultural and Food Chemistry, 57(2):495-502.

Gollasch S; Mecke R, 1996. [English title not available]. (Eingeschleppte Organismen) In: Warnsignale aus der Ostsee [ed. by Lozan JL, Lampe R, Matthaus W, Rachor E, Rumohr H, Westernhagen H] Berlin, : Parey Buchverlag, pp. 146-150.

Gollasch S; Nehring S, 2006. National checklist for aquatic alien species in Germany. Aquatic Invasions, 1(4):245-269.

Hansson HG, 1998. [English title not available]. (Sydskandinaviska marina flercelliga evertebrater. Utgava 2) Miljöavdelningen, Länsstyrelsen Västra Götaland 4, 294 + ix pp., 294 + ix pp.

Harvey-Clark C, 1997. Eastern tidepool and reef: North-Central Atlantic Marinelife Guide. Hancock House Publishers, 64 pp.

Hayes KR; Sliwa C, 2003. Identifying potential marine pests - a deductive approach applied to Australia. Marine Pollution Bulletin, 46(1):91-98.

Hessland I, 1944. [English title not available]. (Petricola pholadiformis - en nordamerikansk mussla under frammarsch pa Sveriges västkust.) Fauna och Flora, 39(1):15-26.

Hill M; Baker R; Broad G; Chandler PJ; Coop GH; Ellis J; Jones D; Hoyland C; Laing I; Longshaw M; Moore N; Parrott D; Pearman D; Preston C; Smith RM; Waters R, 2005. Audit of Non-native species in England. English Nature Research Reports, No 662:82 pp.

ICES, 1972. Report of the working group on introduction of non-indigenous marine organisms. Cooperative Research Reports., 59 pp.

Jensen KR; Knudsen J, 2005. A summary of alien marine benthic invertebrates in Danish waters. Oceanological and Hydrobiological Studies, XXXIV(Supplement 1):137-162.

JNCC, 2009. Joint Nature Conservation Committee.

Loppens K, 1905. [English title not available]. (Animaux marins vivant dans l'eau saumâtre) Annales de la Société Royale Zoologique et Malacologique de Belgique, 40:7-8.

Marshall CE, 2008. Mytilus edulis and piddocks on eulittoral firm clay. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth, : Marine Biological Association of the United Kingdom.

Müller Y, 2004. Faune et flore du littoral du Nord, du Pas-de-Calais et de la Belgique: inventaire. France: Commission Régionale de Biologie Région Nord Pas-de-Calais, 1-307.

Naylor E, 1957. Immigrant marine animals in Great Britain. New Scientist, 2:21-53.

NOBANIS, 2009. North European and Baltic Network on Invasive Alien Species.

Poutiers JM, 1987. Bivalves. In: Fiches FAO d'identification des espèces pour les besoins de la pêche. - Méditerranée et Mer Noire. Zone de pêche 37. Révision 1 [ed. by Fischer W, Schneider M, Bauchot M-L]: CEE, FAO, 369-512.

Purchon RD, 1955. The Morphology of the Rock-Boring Lamellibranch Petricola pholadiformis Lamarck. J. Mar. Biol. Ass. UK, 34:257-278.

Ray GL, 2005. Invasive estuarine and marine animals of California. Technical Notes Collection (ERDC/TN ANSRP-05-2). Vicksburg, MS, : U.S. Army Engineer Research and Development Center.

Rosenthal H, 1980. Implications of transplantations to aquaculture and ecosystems. Marine Fisheries Review, 42:1-14.

Rustad D, 1955. [English title not available]. (Boremuslingen Petricola pholadiformis Lmk., ny for Norge?) Fauna:60-62.

Schlesch H, 1932. Petricola pholadiformis Lamk. in Europe. Naturalist, Lond, 906:213-214.

Tebble N, 1966. British Bivalve Seashells. A Handbook for Identification. Edinburgh, : British Museum (Natural History), Her Majesty's Stationary Office.

Todd JA, 2009. Bivalve life habits. Neogene Marine Niota of Tropical America.

Wolff WJ, 2005. Non-indigenous marine and estuarine species in The Netherlands. Zoologische Mededelingen, 79(1):1-116.

WoRMS, 2009. World Register of Marine Species.

Zenetos A; Gofas S; Russo G; Templado J, 2004. Molluscs [ed. by Briand F]. Monaco: CIESM Publishers.

Zenetos A; Koutsoubas D; Vardala-Theodorou E, 2005. Origin and Vectors of Introduction of Exotic Molluscs in Greek Waters. Belgian Journal of Zoology, 135(2):279-286.

Zenetos A; Ovalis P; Vardala-Theodorou E, 2009. The American piddock Petricola pholadiformis Lamarck, 1818 spreading in the Mediterranean Sea. Aquatic Invasions, 4(2):385-387.

Zorita I; Solaun O; Borja A; Franco J; Muxika I; Pascual M, 2013. Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1989-2008 in the Nervión estuary (southeastern Bay of Biscay). Journal of Sea Research [XVII Iberian Symposium of Marine Biology Studies, Donostia-San Sebastian, Spain, 11-14 September.], 83:104-110.

Links to Websites

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AquaNIS system on aquatic non-indigenous and cryptogenic species
Commission Internationale pour l'Exploration de la mer Mediterranee
DAISIE Delivering Alien Invasive Species Inventories for Europe
EASIN (European Alien Species Information Network) developed by the European Commission’s Joint Research Centre which enables access to data on Alien Species reported in Europe.
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.
Joint Nature Conservation Committee
Marine Life Information Network: Biology and Sensitivity Key Information
NOBANIS (2011) European Network on Invasive Alien Species
World Register of Marine Species (WoRMS)


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15/02/16 Updated by:

Argyro Zenetos, Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research, P.O. BOX 712, Anavissos 19013, Greece

21/07/09 Original text by:

Argyro Zenetos, Institute of Oceanography, Hellenic Centre for Marine Research, P.O. BOX 712, Anavissos 19013, Greece

Distribution Maps

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