American oyster drill (Urosalpinx cinerea)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



The shell of Urosalpinx cinerea is tall and conical with a sharply pointed spire. There are 7-8 whorls. The last whorl has with 10-12 ridges across the whorl and 16-18 prominent spiral lengthway ridges. The shell is yellowish or grey, sometimes with irregular brown marks. The shell is up to 4 cm high and 2 cm broad. The last whorl occupies about 70% of the shell height and the aperture 45-50%.The oval shell aperture has a thin and crenullate outer lip. The external features of the animal are similar to the dog whelk Nucella lapillus. The body is cream with dark markings on the tentacles and mantle edge. The head tentacles are flattened with eyes at the junction with the broader base. The foot is similar to Nucella lapillus.

Recorded distribution in Britain and Ireland

Urosalpinx cinerea is found on the Essex and Kent coasts, especially in estuaries and is associated with oysters.

Global distribution

East coast of the USA.


Found on the lower shore and sublittoral to a depth of about 12 m, feeding especially on oysters.

Depth range


Identifying features

  • Shell tall and conical with a sharply pointed spire.
  • 7-8 rounded whorls bearing pronounced ridges and ribs.
  • Colour yellowish or grey, sometimes with irregular brown marks.
  • Shell up to 4 cm high and 2 cm broad.
  • Siphonal canal is short and open with the siphonal groove bent towards the left.

    Additional information

    Urosalpinx cinerea was an unintentional introduction with American oysters Crassostrea virginica. It has limited adult mobility and the lack of a free-swimming larval stage prevents it spreading quickly. It was severely affected by tributyl tin (TBT) pollution. Urosalpinx cinerea predates native oysters and commercial oyster beds. It feeds by boring through oyster shells. The eggs of Urosalpinx cinerea are laid in capsules attached to oyster shells or stones. Each capsule has about 12 eggs, most of which hatch as juveniles. Urosalpinx cinerea resembles Ocenebra erinacea but the siphonal aperture is closed in Ocenebra erinacea and the shell is rough with uneven sculpturing. Urosalpinx cinerea also has a broader and fatter shell.

    Listed by

    - none -


    1. Cohen, A.N., 2005. Guide to the exotic species of San Francisco Bay.,

    2. Eno, N.C., Clark, R.A. & Sanderson, W.G. (ed.) 1997. Non-native marine species in British waters: a review and directory. Peterborough: Joint Nature Conservation Committee.

    3. Gibson, R., Hextall, B. & Rogers, A., 2001. Photographic guide to the sea and seashore life of Britain and north-west Europe. Oxford: Oxford University Press.

    4. Graham, A., 1988. Molluscs: prosobranchs and pyramellid gastropods (2nd ed.). Leiden: E.J. Brill/Dr W. Backhuys. [Synopses of the British Fauna No. 2]

    5. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

    6. Hayward, P.J. & Ryland, J.S. 1990. The marine fauna of the British Isles and north-west Europe. Oxford: Oxford University Press.


    1. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: accessed via on 2018-09-25.

    2. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: accessed via on 2018-10-01.

    3. NBN (National Biodiversity Network) Atlas. Available from:

    4. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-07-14


    This review can be cited as:

    Oakley, J.A. 2006. Urosalpinx cinerea American oyster drill. 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 14-07-2024]. Available from:

    Last Updated: 10/08/2006