dshubble's picture

Mystery urchin structure

Observed: 4th December 2009 By: dshubble
Leaf Beetle Recording SchemeSouthampton Natural History Society
Invertebrates expert
urchin epi1g
urchin epi1k
urchin epi1p
urchin epi1r

About 0.5mm long (not including threads), fairly numerous and attached to spines of the sea urchin Psammechinus miliaris. After initially having no idea what it was (I thought it was a separate organism), it turns out to be one of the pedicellariae of P. miliaris.

Species interactions

No interactions present.


dshubble's picture


Having now had a look on the web for pedicellariae, I agree that it's exactly what this structure is. I was initially thrown by the lack of a stalk, but now it appears that this is the tip (or 'business end') separated from the stalks that lie all over the surface of the urchin. I've learned more than expected about urchins - thanks!


dejayM's picture


As you see, I have agreed to Andy's as well. He is sorely missed from these pages - wish I'd've known him.