Noetiidae

The Noetiidae are a family of marine bivalve molluscs belonging to the order Arcoida. They are characterized by their small to medium size, equivalve shells, and a hinge line with numerous small, taxodont teeth. Often, they are found attached to hard substrates in shallow-water environments.

Characteristics:

• Shell: Typically small to medium in size, ranging from a few millimeters to a few centimeters in length. The shells are generally equivalve (both valves are similar in size and shape) and inequilateral (the umbo, or beak, is not centrally located). The shell sculpture varies among species but often includes radial ribs or concentric growth lines.
• Hinge: Possesses a straight hinge line with numerous small, similar-sized teeth (taxodont dentition). This is a key characteristic of the Arcoida order.
• Ligament: The ligament, which connects the two valves of the shell, is external and elongated along the hinge line.
• Habitat: Most species are found in shallow marine environments, attached to rocks, coral, or other hard substrates by a byssus (a bundle of strong, silky threads secreted by a gland in the foot).
• Geographic Distribution: Noetiids have a wide geographic distribution, occurring in tropical and temperate waters worldwide.
• Feeding: They are suspension feeders, filtering plankton and other organic particles from the water.

Classification:

The classification of Noetiidae has been subject to revisions over time. Genera within the family include Arcopsis, Noetia, and others. Detailed taxonomic information can be found in databases like the World Register of Marine Species (WoRMS).