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Chamaesipho tasmanica
Each barnacle was about 1 cm high and fused with its neighbour in large mats to form a honeycomb-like colony. The barnacles have 4 non-porous side plates and the free ends are closed by opercular valves whose edges come together to form a "cross".
Seen on rocks at the high tide mark - tidal zone of Port Phillip Bay.
This is the most common of barnacles seen only along the south-east coast of Australia- from NSW to Tasmania. Also found in New Zealand.
These barnacles are found only on rocks and never on wood and are never found in estuaries. In rugged west Victorian coast they can grow to 25 mm , it is reported. Elsewhere on rocky shores they remain the smallest of barnacles.
Barnacles are arthropods, related to crabs and prawns.
Spotted on Nov 20, 2023
Submitted on Nov 23, 2023
3 Comments
To John, thanks for your comments. I am constantly learning too...I did not know of these barnacles until I spotted huge spreads of such small ones on rocks and then of course I read about them.
Yes, they are arthropods. When under water and open, you can see feathery structures ( filter baskets) from their legs flick in and out and catch food particles.
To Ava, thanks for your generous comment.
Thanks Leuba for your excellent spotting, and John B. for your self-effacing comment. You are both treasures.
Hi Leuba,
I always like your notes as I learn something new from them every time, but your last sentence really shocked me because it made me realize that there was a huge, embarrassing gap in my knowledge and I was completely unaware of it until now. I have always thought that barnacles were molluscs, but now I know that they are arthropods, not cephalopods. Thank you for that last sentence. Now all I have to do is click on the "Post comment" button and expose my ignorance to everyone....or will I take the easy way out and just erase .... Here goes...