Mike Schilperoort took this photo on Fish Hoek beach yesterday morning. He asks what type of mussels they are.
I checked with Prof George Branch, co- author of Two Oceans: A guide to the marine life of southern Africa (authored by GM Branch, CL Griffiths, ML Branch and LE Beckley) as to whether they were goose barnacles and his response was:
“Yup: Correct. Despite these animals having an external shell and looking a bit like a mussel, they are relatives of shrimps and lobsters (Crustacea) and have jointed limbs like all arthropods. This particular goose barnacle is Lepas testudinata.”
These goose barnacles attach themselves to floating driftwood and other objects by means of their long fleshy stalks. According to Prof Branch’s book, their common name “originates from the medieval myth that these barnacles grow into Barnacle Geese!”
Two Oceans: A guide to the marine life of southern Africa is a must have for those interested in all creatures marine.
See also an earlier article about the rare bouy barnacle, specimens of which were washed up at Fish Hoek beach last year http://scenicsouth.co.za//2011/11/bouy-barnacles-found-on-fish-hoek-beach/.