Variable Wormsnail
Petaloconchus varians (d'Orbigny, 1839)
Family Vermetidae
Variable Wormsnails form large "worm rocks" and reefs of these colonies are found offshore. These worm rocks break off and come ashore and may be found regularly on S. Hutchinson Island beaches. Pictured below is a group of Variable Wormsnails about 6" by 6" which almost resemble a human brain:
A clump of Variable Wormsnails: S. Hutchinson Island, January 2021
Harry Lee: The worm rock is a blanched colony of Petaloconchus varians (d’Orbigny, 1841) Variable Wormsnail. Some people believe that name is based on unrecognizable (and lost) type material, and they employ the scientific name Petaloconchus nigricans (Dall, 1884) . Either way, the vernacular name is OK.
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Family Vermetidae
Petaloconchus varians
(d'Orbigny, 1839)
Variable Worm Snail
Shell size (diameter) to 7 mm; a colonial gastropod that may form massive offshore reef-like structures. Usually found as clumps of calcareous tubes in shades of brown color. Tubes are usually about 7 mm in diameter and may have a finely reticulated surface sculpture.