64 — Stalked barnacle, Smilium spinosa

A stalked barnacle, in a cave at north
Piha, 26/12/15.

A stalked barnacle, in a cave at north
Piha, 26/12/15.

A stalked barnacle, in a cave at north
Piha, 26/12/15.

Most of the barnacles people are familiar with are the acorn barnacles seen on rocks between the tides. However, they are not the only kind of barnacle. There are also stalked barnacles. These are barnacles which have a flexible stalk attaching them to the rocks, rather than a calcareous base.

Stalked barnacles are not as common as acorn barnacles, but can be found if you are patient and know where to look. Smilium spinosa* is a stalked barnacle often seen in caves and dark crevices around the New Zealand coastline. There a few species of stalked barnacle found around New Zealand and this is the largest and most common.

Why they live in caves is not clear. It could be to avoid predators or to protect them from desiccation.

They are about 30–40mm in size and commonly seen in the caves at the northern end of Piha beach, which is where the these pictures were taken. They co-occur with the anemone Actinia tenebrosa (which are the red blobs).

*(Quoy & Gaimard, 1834)








More info: 

http://rsnz.natlib.govt.nz/volume/rsnz_83/rsnz_83_02_005360.pdf