dejayM's picture

Trivia and Ascidian

Observed: 8th June 2013 By: dejayM
Biological Recording In ScotlandHighland Biological Recording GroupOrkney Biodiversity Records Centre
dejayM’s reputation in InvertebratesdejayM’s reputation in InvertebratesdejayM’s reputation in InvertebratesdejayM’s reputation in Invertebrates
the ascidian
3 for 20p

A Groatie Buckie (Trivia monacha) on its preferred food source - an Ascidian.
Two sorts of Groatie, one without spots too.
I have found many shells on the North Sea coasts; this is my first from Scapa Flow and my first ever live one.
See comment

Species interactions

No interactions present.


dejayM's picture


Star Ascidian is a Sea squirt colony (Bryozoa).
The structure and identity of these yellow ones is the subject of a debate here

JoC's picture

star ascidians

are usually placed in the hemi-chordates, not Bryozoa.


dejayM's picture


That's fair, I had read this in H&R
Phylum Chordata: Subphyllum Urochordata (=Tunicta) which I think is one step removed...
but was afraid to overstep my meagre experience.
I have YET to look at the systematic way Phylum, Class, Order, Family and Genus are sorted - particularly for the squidgy things.

The post was for you specially Jo. - see

DivingDave1980's picture


The non-spotted cowrie (groatie) is likely to be Trivia arctica. If I remember correctly there are two species of cowrie (groatie) in the UK - one with spots (monacha) and the other without (arctica).

DivingDave1980's picture

But not all that simple...

This post suggests that it is more complicated than a simple lack of spots and that juvenile monacha also lack spots. Just for info...

dejayM's picture

third picture

Yes David, thanks. It's true that they are sometimes very difficult to separate and my third pic above does not help.
See also

DivingDave1980's picture

Thanks for the... I love the picture linked to - very macabre!

I have some pics of Trivia underwater, which aren't great. I'll be sure to look out for them when I'm diving this weekend...


dejayM's picture


Dave welcome back - (recent marine agreements). I have another T.arctica here - read the comments, so valuable.
Time for some more posts then?