Cardiida

Common Names

Cardiida is a large and diverse group of bivalves, so there is no single common name for the entire order. However, many of the species in this order are commonly known as clams, cockles, or scallops.

Characteristics

Cardiida is a diverse order of bivalves, and members exhibit a wide range of characteristics. However, there are some common features that help to distinguish Cardiids from other bivalve orders:

• Well-developed hinge teeth: The hinge teeth are located on the dorsal side of the shell and are used to lock the two valves together. Cardiids typically have a robust hinge plate with multiple, well-developed hinge teeth.
• Presence of a pallial sinus: The pallial sinus is a deep indentation in the mantle edge that allows the bivalve to retract its siphons into the shell. The size and shape of the pallial sinus can vary between species and is often used for identification.
• Two adductor muscles: Like all bivalves, Cardiids have two adductor muscles that are used to close the shell. The anterior adductor muscle is typically smaller than the posterior adductor muscle.
• Siphons: Many Cardiids have siphons, which are tubes that extend from the mantle and allow the bivalve to draw in water and filter out food.

Environments

Cardiids are found in a wide variety of marine environments, including:

• Intertidal zones: Many Cardiids live in the intertidal zone, where they are exposed to air and water twice a day. These species are often adapted to tolerate changes in salinity and temperature.
• Subtidal zones: Other Cardiids live in the subtidal zone, where they are always submerged in water. These species are often found in sandy, muddy, or rocky habitats.
• Deep sea: Some Cardiids live in the deep sea, where they may be found at depths of several thousand meters.

References

For more information about Cardiida, please visit the following websites:

• World Register of Marine Species
• National Center for Biotechnology Information (NCBI)
• Wikipedia