Lyncina carneola

Lyncina carneola (Linnaeus, 1758)
Carnelian cowry, 20-48mm

Lyncina carneola might occupy the widest range of Marshall Islands habitats. They can be found commonly under rocks from the intertidal reef on down as least to 45m and deeper in the lagoon and on the seaward slope. Within the lagoon, they can be found under rocks along shallow interisland reefs on both leeward and windward shores. Dead empty shells are abundant in oceanside surge channels and common on deep lagoon shipwrecks. In shell color and pattern, this species is almost identical to one or perhaps two other cowries, Lyncina leviathan and L. propinqua. We have to admit we still have trouble telling them apart, and feel that some of the characters that have been used to differentiate them are not consistent. The shell of Lyncina carneola is smaller and smoother along the margins than L. leviathan, which tends to have an irregularly bumpy margin. Lyncina carneola and L. propinqua are said to usually have a diffuse bluish-white band between the dorsal orange and brownish marginal coloration; this is clearly visible in the first and several other photos below. Lyncina leviathan is supposed to always lack this bluish-white band. But the real difference that has been given in the past is in the animal. In addition to consistent and distinct differences in the radulae of L. carneola and L. leviathan, the mantle papillae have been reported to be quite different. The papillae on the mantle of Lyncina carneola are supposed to be mostly small spike-shaped projections, interspersed with larger flat ones that have several fingerlike branches near the top. The larger papillae on Lyncina leviathan are more tree-like with numeous branches. The other shell that might represent another species or may be just a form of L. carneola is L. propinqua. Lyncina propinqua is supposed to differ from L. carneola in part in the structure of its mantle papillae, which are square flattened sails with serrated tops. Burgess (1985) considered L. propinqua distinct from L. carneola, but Lorenz & Hubert (2000) consider L. carneola propinqua a subspecies of L. carneola. Lacking other evidence, and since we couldn't find a photo in our collection that clearly fit the description of L. propinqua, we are inclined to agree with Lorenz and Hubert, but are keeping our options open. A few more comments about the mantle papillae of the different species are interspersed with the photos below. Lyncina carneola is known from most of the Indo-Pacific.

Here is a close view of some of the larger papillae from the specimen above. Would these be considered flat with fingerlike branches near the top? Maybe.

The specimens above and below clearly have the bluish-white band (less clean in the photo below) separating the dorsal from the marginal coloration. However, the papillae of the photo above look like some more problematic photos below (the 4th and 5th).

This slightly fuzzy shot, taken in the Solomon Islands, illustrates papillae that seem to me to more closely match the description of Lyncina carneola, which Burgess says are round at the base with "flat blunt branches that closely resemble the flattened human hand with the fingers spread on the same plane." It also matches the color photo on page 80 of Burgess (1985). Or would these be better considered square flattened sails with serrated tops, as described for L. propinqua? Compare this with the following two photos.

The next three shots illustrate a specimen we considered Lyncina carneola due to its small size and lack of bumps along the lateral shell margins. However, its papillae are distinctly branched up near the top, much more like Lyncina leviathan's "shavingbrush-like dendritic papillae" of Lorenz & Hubert (2000, p69). Of course, this could have been a small L. leviathan with no lateral bumps, but its papillae seem to us at least similar to the obvious L. carneola in the first photo on this page. We think this group of cowries has a fair bit more work that needs to be done on it. In particular, we would be interested in seeing the results of DNA analysis on particular specimens whose living anatomical features have also been clearly photographed for comparison.