Biodiversity of the Central Coast
  • Biodiversity of the Central Coast - Home
  • About the Central Coast
    • Location
    • Communities
    • Environment >
      • Hakai Institute weather stations and webcams
    • Visitors
  • Species Guide
    • Plants >
      • Woody Vascular Plants >
        • Trees
        • Shrubs
      • Non-woody Vascular Plants >
        • Wildflowers
        • Grasses, Sedges, and Rushes
        • Ferns, Horsetails, Clubmosses, and more
      • Non-vascular Plants >
        • Mosses and Liverworts
        • Lichens
    • Fungi and Slime Molds
    • Seaweeds (Algae) and Seagrasses >
      • Red Seaweeds
      • Brown Seaweeds
      • Green Seaweeds
      • Seagrasses
      • All Seaweeds and Seagrasses
    • Birds >
      • Waterbirds and Shorebirds
      • Songbirds
      • Birds of Prey
      • Woodpeckers and Hummingbirds
      • Other Birds
      • All Birds
    • Land Animals >
      • Land Invertebrates
      • Amphibians and Reptiles
      • Land Mammals
    • Marine Animals >
      • Marine Invertebrates >
        • Bryozoans
        • Echinoderms
        • Cnidarians
        • Crustaceans
        • Molluscs
        • Sponges
        • Tunicates
        • Marine Worms
      • Fish
      • Marine Mammals
      • All Marine Animals
    • Species At Risk
    • All Species
  • Identification Resources
  • Research
  • Media and Links
  • Resources for Educators
  • Gallery
  • About This Site
    • Acknowledgements
    • Contact and Contribute

Expanded macoma • Rexithaerus expansa, formerly Macoma expansa

Expanded macoma (Macoma expansa)
Expanded macoma (Macoma expansa)
A broken expanded macoma shell from the bivalve collection at the Hakai Institute's Calvert Island field station. Photographed by Kelly Fretwell.

Identification
This clam has a white oval-shaped shell, with one end (anterior) shorter than the other (click here for information on shell orientation). The exterior of the shell has a varnished appearance, sometimes with a yellowish periostracum. The shell reaches 5 cm long.

Habitat & Range
The expanded macoma is a less common species, and is found buried in sand in the intertidal and subtidal to 30 m deep. It inhabits exposed shorelines from the Aleutian Islands in Alaska to central California.

References
​Harbo, R. M. (1997) Shells & Shellfish of the Pacific Northwest. Madeira Park, BC: Harbour Publishing. P. 153.
​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 (2017).
Picture
Picture
Picture
Picture
Picture