Translucent Screw Shell, Vermicularia pellucida 

Translucent Screw Shell, Vermicularia pellucida. Shell collected off the beach in the greater Los Cabos area, Baja California Sur, May 2011. Size: 4.0 cm (1.6 inches) x 2.0 cm (0.8 inches).

Phylogeny: The Translucent Screw Shell, Vermicularia pellucida (Broderip & G. B. Sowerby I, 1829), is a gastropod mollusk that is a member of the Turretellidae Family of Turret Shells. The genus Vermicularia is one of twenty-four genera in this family, and there are seven species in this genus. They are also known as the Eburnea Screw Shell and in Mexico as Caracol Tornillo.

Description: Translucent Screw Shells are named for their thin walls that are translucent. As juveniles that look very much like other Turret Shells, however, as they mature the whorls separate and the shell grows in random directions. These shells can become intertwined with other Translucent Screw Shells growing nearby, forming an inseparable cluster of individuals. The exterior of the shell is white to yellowish tan in color.  Translucent Screw Shells reach a maximum of 6.0 cm (2.4 inches) in length and 3.0 cm (1.2 inches) in height.

Habitat and Distribution: Translucent Screws are found anchored in coarse substrates such as gravel and rubble within the intertidal zone, and at depths up to at least 30 m (100 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean.

Ecology and Behavior:  Translucent Screws are suspension feeders, which use mucous strings to capture plankton and suspended organic matter. They are gonochoric. Reproduction is sexual, with internal fertilization. Their engagement in any form of commensal, parasitic, or symbiotic relationships has not been formally documented. From a conservation perspective the Translucent Screw has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Vermetus eburneus, Vermetus fewkesi, Vermetus pellucidus, Vermicularia fewkesi, Vermicularia pellucida eburnea, Vermicularia pellucida pellucida, Vermiculus pellucidus, and Vermiculus pellucidus var. planorboides.