Mussel Shells of the Mytilidae Family

Three Mussel Shells of the Mytilidae Family can be found in this website:

Phylogeny: Mussel Shells of the Mytilidae Family are a bivalve mollusks that are in the order Mytilida. This order is comprised of one superfamily- Mytiloidea.  The superfamily Mytiloidea consists of two families- Mytilidae and Modiolidae. The Mytilidae Family is large and is comprised of eight subfamilies, thirty-two genera, and around two hundred fifty species. Shells in this family are also commonly known as Mytilids.

Description: Mussel Shells are ovate to ellipsoid in outline and inflated in profile. They are equivalve with both valves being identical in size and shape. The shells are thinly constructed, but strong. The hinge plate is long and narrow. Mussel Shells may be smooth or sculpted with radial ribs or commarginal striae. Their interiors are nacreous. They tend to be whitish, gray, brown, purplish-brown, or blue in color. Most are covered with a moderate to thick periostracum. Mussel Shells range from small to large in size. The largest species reach 25 cm (9.7 inches) in length.

Habitat and Distribution: Mussel Shells are generally found attached to rocks and other hard surfaces with a strong byssus (thread-like anchor lines). Some burrow into hard substrates, like coral. A few are found on soft substrates. They often form thick colonies on rocks or pilings. They live in the intertidal zone and range to the deepest parts of the ocean at depths exceeding 11,000 m (36,000 feet). Mussel Shells are found worldwide in tropical to polar waters, and in both fresh and saltwater. Forty species of the Mytilidae Family are found in the marine waters of Mexico.

Natural History: Mussel Shells are suspension feeders, eating plankton and detritus collected from the surrounding water. In turn they are preyed upon by shorebirds, crabs, fish, sea stars, and gastropods. Mussel Shells are gonochoric and reproduce sexually. Marine mussels utilize broadcast spawning with external fertilization. Fresh water mussels utilize spermcasting with internal fertilization. Many mussel species are edible and have been consumed by humans for thousands of years. Some species are harvested recreationally and commercially for food and also for fish bait. Many Mussel Shell species are considered to be fouling organisms, which damage infrastructure. They can also be highly invasive and difficult to control.