Physical Description

Shape and Size

Cypraea xanthodon is a species of cowrie, and as such, has a shiny, polished external shell. This is due to the fact that they are able to completely, or nearly completely enclose their shell within their mantle. Cowrie shells appear to be bilateral because the coiling of the shell is completely surrounded by the outer whorl of the shell. The aperture, or opening of the shell is slightly off-centre and continues the entire length of the shell. They also have obvious teeth along both sides of the opening.  The bottom of the shell slightly bulges out in this species, but not to the extent of other species (for example, see Cypraea annulus).

The shells of other cowrie species have been found to stop growing once they reach their adult form and this is hypothesised to be the same for all species. C. xanthodon grow up to 30 – 38 mm (Jansen 1995; Rippingale & McMichael 1961).

            
                          (adapted from Smithsonian 2012)

Colouration

For the individuals found on Heron Island, the pattern of the upper part of the shell, as seen in the image above, has three dark bands interspaced by two lighter bands. These bands are then overlayed by small brown specs which vary in size. The bottom, or anterior, part of the shell contrasts the posterior side, having a pastel pink to cream colouration with larger black to brown spots. These spots can intrude into the pattern above. Other variations of this specie’s colouration have been described, with dark green to blue colouration of the upper part of the shell (Rippingale & McMichael 1961).

The mantle which covers the shell of C. xanthodon, as with other cowries has many projections, which have been described by some to be coral polyp-like in appearance, which may provide clues as to their purpose. The mantle of C. xanthodon is transparent with white lace-like patterns extending out from the projections. The mantle margin has bands of black and white, which are distinguishable from the rest of the mantle. The mantle projections appear to be white to light brown in colour, varying within an individual with no recognisable pattern.
                                      

Cephalic features

The siphon, as can be seen in the photo, is creamy in colour and is able to protrude significantly from the shell. The siphon has finger-like projections along its margin. C. xanthodon also has two tentacles, just in front of the eyes, which are bright orangey-yellow, in stark contrast to the more subdued colours of the rest of the individual. The mouth is situated directly underneath the siphon and is also orange in colour.