Radiant Button Shell, Pusula radians

Radiant Button Shell, Pusula radians. Shell collected off the beach of El Mezquital, Baja California Sur, December 2022. Size: 2.2 cm  (0.9 inches) x 1.1 cm (0.4 inches) x 1.1 cm (0.4 inches). Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Radiant Button Shell, Pusula radians. Shell collected off the beach of El Mezquital, Baja California Sur, December 2022. Size: 2.3 cm  (0.9 inches) x 1.7 cm (0.7 inches) x 1.1 cm (0.4 inches). Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

The Radiant Button, Pusula radians (Lamarck, 1810), is a gastropod mollusk that is a member of the Triviidae Family of Trivias. They are also known as Radiating Trivia.

The shells have an ovate profile and are a dark brown to a pinkish light sand color with large brown spots and wart-like tubercles on the dorsum and strong transverse ribs on the base.  The aperture runs the length of the shell and has teeth along the margins. The Radiant Button Shells reach a maximum of 2.1 cm (0.8 inches) in length and 1.5 (0.8 inches) in diameter.

The Radiant Buttons reside attached to and under rocks in the intertidal zone. When actively feeding the mollusk its soft mantle sides emerge and join together at the mid-line of the back. In Mexico they are found throughout the Pacific Ocean with the exception they are absent from north of Magdalena Bay northward along the central and western coasts of the Baja.

The Radiant Button Shell is very similar to the Coffee Bean Shell, Pseudopusula californiana (larger in stature with ribs that do not cross the midline).

A synonym is Cypraea radians.