Pterynotus elongatus (Lightfoot, 1786)
89.9mm

Pterynotus elongatus is rare in the Marshalls. A few specimens have been found on lagoon pinnacles, but mostly they are exposed on hard reef or rubble at the upper edge of the seaward reef slope, where they blend in well with their surroundings.

The animal coloration is similar to Pterynotus martinetanus and P. bipinnatus . The young specimen immediately below was photographed in Hawaii.

This young individual had an orange shell.

This tiny juvenile appears to be either a P. elongatus or P. tripterus.

Adult shells have elongate spires such as the one at left below. One specimen (center) was found that had a very short, stubby but intact spire. At first glance, the encrusted shell appeared to be a Pterynotus tripterus (right). However, the shape of the outer margin and the remnant wings near the top of the spire clearly ally it with Pterynotus elongatus. It seems most likely this is a deformed P. elongatus, but we have not completely ruled out the possibility of a hybrid with Pterynotus tripterus.

Here are top and bottom views of the questionable P. elongatus. The smooth aperture is another feature of P. elongatus; Pterynotus tripterus has distinct denticles around the inner edge of the aperture.

Created 1 October 2010
Updated 16 March 2020

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