Naviculavolva kurziana (Cate, 1976)
Kurz' egg shell, 17mm

Naviculavolva kurziana is relatively common in the Marshalls. It is found exclusively on the gorgonian Rumphella, which is often erroneously called "black coral" here in the Marshalls. Rumphella is definitely a gorgonian (soft coral) and is quite distinct from true black corals. Naviculavolva kurziana and two look-alike species, N. deflexa and N. malaita, all feed on Rumphella. During the day, they usually hide in holes or tufts of algae and debris around the base of the gorgonian, coming out onto the branches at night to feed. We long considered all the little egg shells living on Rumphella to be the same species, but have been informed by experts in the group that there are indeed three different species. N. deflexa differs externally in having an orange or yellow line circling around the lower sides of the shell, just above the base. N. malaita has a shell that is finely striated; the other two species are smooth. We have seen no studies on the animals' anatomy or biochemistry (DNA) to confirm or deny these differences, but for now we are keeping them separate. Although we seem to have photos only of N. kurziana and N. malaita, we have seen all three species, sometimes intermixed on the same colony of Rumphella.

The two specimens below are flanked by the spiny arms of a brittle star. The black patch on the thick gorgonian stalk just above the larger shell is the gorgonian's black skeleton showing through where the brown tissue has been grazed away by the mollusks.

Created 22 September 2008
Updated 9 July 2009

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