Western ringed lucine • Lucinoma annulatum

Photo by Angeleen Olson.
Identification
Like other lucine clams (Family Lucinidae), the western ringed lucine's shell valves are almost circular, with flattened edges near the hinge (the clam's dorsal margin; click here for information on shell orientation). The shell is compressed into a relatively flattened shape, and the valves are lined with sharp, evenly-spaced, rounded ridges. The white shell is covered with a thin greenish-brown layer of periostracum. This clam grows to 8.2 cm across.
Habitat & Range
The western ringed lucine can be found in muddy-sandy substrates in the intertidal and subtidal to 750 m deep. Its range extends from central Alaska to the Gulf of California.
Similar Species
The rough diplodon (Diplodonta impolita) also has a circular shell; this shell is more inflated (not as flat), and is lined with less evenly-spaced ridges.
Intriguing Info
The sharp ridges on the shell valves are growth lines which represent growth intervals rather than years.
iNaturalist
https://www.inaturalist.org/taxa/496449-Lucinoma-annulatum
Like other lucine clams (Family Lucinidae), the western ringed lucine's shell valves are almost circular, with flattened edges near the hinge (the clam's dorsal margin; click here for information on shell orientation). The shell is compressed into a relatively flattened shape, and the valves are lined with sharp, evenly-spaced, rounded ridges. The white shell is covered with a thin greenish-brown layer of periostracum. This clam grows to 8.2 cm across.
Habitat & Range
The western ringed lucine can be found in muddy-sandy substrates in the intertidal and subtidal to 750 m deep. Its range extends from central Alaska to the Gulf of California.
Similar Species
The rough diplodon (Diplodonta impolita) also has a circular shell; this shell is more inflated (not as flat), and is lined with less evenly-spaced ridges.
Intriguing Info
The sharp ridges on the shell valves are growth lines which represent growth intervals rather than years.
iNaturalist
https://www.inaturalist.org/taxa/496449-Lucinoma-annulatum
References
Harbo, R. M. (1997) Shells & Shellfish of the Pacific Northwest. Madeira Park, BC: Harbour Publishing. Pp. 145-146.
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Authors and editors of page
Kelly Fretwell (2016).
Harbo, R. M. (1997) Shells & Shellfish of the Pacific Northwest. Madeira Park, BC: Harbour Publishing. Pp. 145-146.
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Authors and editors of page
Kelly Fretwell (2016).