Staphylaea semiplota (Mighels, 1845)
Half-swimmer cowry, 20mm

Staphylaea semiplota was apparently quite common around Oahu in the 1940s, but apparently disappeared in the 50s. Many earlier records were from the Waikiki area, which started to change greatly with the growth of hotels along the beach during that period. Possible the habitat was altered too much for the species. Only an occasional specimen was reported in the Hawaiian Shell News over the next couple of decades. In the mid 1970s, specimens began to show up on the reef at Fort Kam, near the mouth of Pearl Harbor, at depths of 1 to 4m, and on a reef directly offshore from there at 13-15m. While they did not again become common, they were not hard to find. This species is endemic to the Hawaiian Islands. We found many empty shells along the beach of Green Island at Kure Atoll in 1979, suggesting they may be more common in the northwestern Hawaiian chain.

Occasional specimens become frosted with white, and were given the name annae. Now it is considered a variety of S. semiplota.

19.0 specimen below.

15.2mm specimen below.

Created 25 July 2010
Updated 25 December 2020

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