Six-plated Barnacle

Description:

Encrustations of barnacles on a beach-groyne. These barnacles had broad bases with six hard peripheral plates and two top plates, forming the operculum. Some barnacles showed smooth plates (pic 2/3) while some had plates with ridges (pic 4).

Habitat:

Found studding a beach-groyne ( a wooden "fence" perpendicular to the shore line to stop sand drift/erosion ) high up on the shore. This part of the beach is submerged during high tides.

Notes:

These might seem uninteresting encrustations but are really fascinating relatives of crabs, prawns. The link below has interesting information
http://www.mesa.edu.au/friends/seashores... The plates on the barnacle in pic 2 are heavily worn. Barnacles like the one in pic 4 show ridged plates that might indicate less intra-species competition. http://www.mesa.edu.au/friends/seashores...
Subphylum: Crustacea Class: Maxillopoda Subclass: Thecostraca Infraclass: Cirripedia