The ‘purple-under-a-stone’ sea cucumber as named in Ria’s wildfact sheets is identified as Afrocucumis africana! This was reported in a short note in Nature in Singapore which me, Lionel and some other friends from plant systematics lab did. You may click on the picture to download the free article.
We have another sea cucumber article in review (which was actually submitted before this paper, but for some reason delayed). Watch out for it!