For our October Shell of the Month we have three specimens of Oliva irisans Lamarck, 1811, one orange, one black and an unusual one overlaid with brown yet revealing the pattern underneath. Typical specimens, if there is such a thing, are whitish with faint overall mottling and big bold streaks of brown. Possibly the typical pattern has two interrupted brown bands instead.
Olives are scavengers, generally found burrowed in sand with just their siphon exposed. They are communal by nature and will share a meal. Up until anout10 years ago olives were abundant off the coast of Broward County. They were easily collected on the off shore sandbars that weould be exposed at low tide. After a heavy storm dozens would be found washed up on the beach. Wiith all the beach reconstructions and dredging in recent years, they are no more. On the west coast olives are still abundant.
Olives are fun to collect as there are so many species. Most are colorful, the patterns are interesting and varied and most all are small in size. Identifification is another story all together as olives are all so similar. Olives have been named and renamed so one needs a very current book to have the latest name. There is a good chance the name on the label of a specimen one bought few years ago is no longer valid.
Oliva irisans Lamarck, 1811is sometimes mislabeled as Oliva lignaria Marrat, 1868 as they are quite similar.. Irisans is distinguished by the heavy callous on the apex and spire. The color varieties of irisans all have individual names which are not currently recognized, but still used in the trade.
Two of the specimens are from the Philippines and the third is from Indonesia. They are matched in size and about gem in condition. Donated from the collection of Richard Kent