U is for URCHINS and not anything else on Jessica’s Nature Blog. Not many sea urchin pictures but here they are. The remaining few letters of the alphabet will be similarly challenging. I wonder what I can find.
https://natureinfocus.blog
I always find sea urchins very appealing, I think its a combination of their varied colours and spikiness.
I don’t know anything about sea urchins but your photos have made me curious. And what great images you’ve captured.
regular and irregular echinoids
Yes, they are attractive to look at, and it’s fascinating to observe at close quarters the way their spines are arranged in a pentamerous fashion, each one attached and articulating on a small tubercle.
Thank you, Claudia.
Yes, the shape of the test varies quite a bit between the species even though they are all built to the same basic design with a five way pentamerous symmetry, just like other members of the Ecinodermata like starfish and sea cucumbers.