Ophiothela mirabilis

Ophiothela mirabilis is a very minute brittle star, which rarely reaches more than 1 cm including arms. It has in general 6 arms, however because of its mode of reproduction by division (scissiparity), its shape is often very irregular (one half more developed than the other, only 4 or 5 arms, or on the contrary 7 or 8...).

Its coloration is extremely variable and made believe for a long time in a complex of several species: it can thus be orange plain or white mottled with bright colors (in particular yellow and blue) with ringed arms.[1]

All have arms with delicate translucent, thorny spines. The arms are flexible in all directions. The jaws contain clusters of well-developed tooth papillae on the apex but not on the sides. There are no mouth papillae. Inside the mouth edge there is a second pair of tube feet. The dorsal surface of the disc is covered with spines and thorny towers.

The former species Ophiothela danae is now considered a junior synonym of Ophiothela mirabilis.[1]

Ophiothela mirabilis is found in the tropical ecosystems of the Indo-Pacific, where it lives coiled, sometimes in hundreds, on larger animals (sponges, echinoderms, gorgonians, corals...).[2]

Recently, it has appeared in the Caribbean, where it seems to be becoming invasive: it has probably been transported by commercial ships.[1]

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  With 7 arms
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  Wrapped by dozens around a gorgonian
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  Preserved specimen
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Media related to Ophiothela mirabilis at Wikimedia Commons