Vesicularia spinosa (Linnaeus, 1767)

Growth: 

Colonies form erect, slender tufts.

Look alikes: 

This species may be confused with some of the Bugula species and possibly with erect hydroids such as Sertularia cupressina.

Morphology: 

Colonies form erect, dense tufts; these are light grey-brown in colour and appear as slender plumes rather than spreading bushy tufts. The tufts can grow up to 30cm long in clumps. The autozooids develop into branches that divide in a regular dichotomous or trichotomous pattern. This gives the colony a very distinctive zig-zag appearance.

Size: 

Colonies are often 50-60mm long, however, in well-developed specimens they can reach 300mm or more. Autozooids are 0.45x0.2mm and are squat, cylindrical shaped structures, attached to kenozooidal branches.

Distribution: 

Vesicularia spinosa has been reported from all British coasts, from the southern English Channel and from the coasts of Ireland. There is a lack of contemporary records for this species. It may be poorly recorded.

Ecology: 

Very little is known of its biology or ecology. The arrangement of the short branches around the main stem of the colony leads it to accumulate a layer of sediment giving the colonies a ‘cruddy’ appearance.

Habitat: 

Vesicularia spinosa occurs on the lower shore and into the subtidal zone. It is often attached to small stones or shell gravel.

Trophic strategy: 

In this species the polypide is quite large with 8 feeding tentacles.