Scaled Jewel Box Shell, Chama squamuligera

Scaled Jewel Box Shell, Chama squamuligera. Size: 1.9 cm (0.7 inches) x 1.6 cm (0.6 inches). Shell collected from the tidal pools within El Tule, Km 17, Baja California Sur, March 2010.

Phylogeny: The Scaled Jewel Box Shell, Chama echinata (Broderip, 1835), is a bivalve mollusk that is a member of the Chamidae Family of Jewel Boxes. The genus Chama is one of six genera in this family, and there are forty-two species in this genus. They are also known as the Spiny Jewel Box, and  in Mexico as Almeja Joyero.

Description: The Scaled Jewel Box Shell is chunky and irregularly circular in shape. Their shape is determined by the contour of the substrate to which they attach. The left valve is slightly larger and more curved than the right. The left valve is also the valve that attaches to the substrate. The exterior surface is covered with short, irregular spines. The interior margin may be crenulate to pustulate. These shells have a cream colored exterior, occasionally with pink on the base and spines. The interior is cream colored and may have pink or orange blush.  Scaled Jewel Box Shells reach a maximum of 3.8 cm (1.5 inches) in length and 3.2 cm (1.3 inches) in height.

Habitat and Distribution: Scaled Jewel Boxes are found attached to rocks and coral in the intertidal zone, and to depths up to 90 m (295 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean, including the Revillagigedo Islands, with the exception that they are absent from north of Cedros Island, Baja California, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior:  Scaled Jewel Boxes are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective they have not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Chama garthi and Chama squamuligera.