The Exotics Guide

Littorina littorea (Linnaeus, 1758)

COMMON PERIWINKLE

  • Kingdom: Animalia
  • Phylum: Mollusca
  • Class: Gastropoda
  • Order: Neotaenioglossa
  • Family: Littorinidae

Littorina littorea is a European periwinkle that has become established in eastern North America. Though it has been found on the Pacific Coast on several occasions ranging from discoveries of single individuals to populations of several thousand snails, most of these have died out (sometimes assisted by eradication efforts), and it is not yet known to be established. Littorina littorea often occurs in the seaweed used to pack shipments of New England bait worms and lobsters, and is also sold as live seafood in Asian food markets in California.

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Styela clava 5-another view of 3 individuals

Another view of three of the Styela clava in the previous image, with bits of red and green seaweed growing on them.

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Styela clava 4-four on mussel

A mussel (Mytilus trossulus-galloprovincialis complex) collected in San Francisco Bay with 4 Styela clava growing on it, the smallest one lacking a stalk. A green seaweed (Ulva sp.) is also growing on the mussel.

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Styela clava 3-upper end

The upper end of a Styela clava on an intertidal rock in San Francisco Bay.

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Styela clava 2-three hanging

Three Styela clava hanging from the underside of a rock in large riprap in San Francisco Bay. There are two white barnacles (Balanus glandula) and a gray, flat encrusting bryozoan (Conopeum sp.) growing on the middle specimen. A gray fuzzy bryozoan (Bowerbankia sp.) covers part of the right-hand specimen. A red and black bryozoan (Watersipora subtorquata) encrusts some of the rocks.

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Styela clava Key Image

Styela clava collected in San Francisco Bay. Note the stout stalks and brown, bumpy skin. The two bumps at the very top of the middle and right-hand specimens are the inhalant and exhalant siphons.

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Styela clava Herdman, 1881

CLUB SEA SQUIRT, CLUB TUNICATE, ASIAN TUNICATE, LEATHERY SEA SQUIRT, ROUGH SEA SQUIRT

  • Kingdom: Animalia
  • Phylum: Chordata
  • Subphylum: Tunicata
  • Class: Ascidiacea
  • Order: Stolidobranchia
  • Family: Styelidae

Styela clava is a solitary sea squirt with a leathery, bumpy and often wrinkled outer skin that is yellowish or dark brown. It commonly grows to 8-12 cm long, with the largest reported specimens reaching 20 cm. Its overall shape is club-like, with a cylindrical body that tapers either abruptly or gradually to a sturdy stalk attached to rock, wood, shell or some other hard surface. The base of the stalk sometimes spreads out into a thin plate, up to 2.5 cm across, encrusting the surface.

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Didemnum 9-Georges Bank

Didemnum sp. A covering gravel bottom at 47 m depth on Georges Bank in the Gulf of Maine.

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Didemnum 8-closeup of surface

Closeup of the surface of a Didemnum sp. A colony, from San Francisco Bay.

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Didemnum Key Image

Detail of a Didemnum sp. A colony from San Francisco Bay.

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