Scallop Shells of the Pectinidae Family

Six Scallop Shells of the Pectinidae Family can be found in this website:

Phylogeny: Scallop Shells of the Pectinidae Family are bivalve mollusks in the order Pectinida. The superfamily Pectinoidea is one of four superfamilies within this order. The superfamily Pectinoidea consists of four families. The Pectinidae Family is large, being comprised of five subfamilies, sixty-five genera, and around two hundred sixty-three species. Shells in this family are also commonly known as Pectens (derived from the Latin word for “comb”) or Pectinids.

Description: Scallop shells have a trigonal to circular profile with a flat edge at the hinge. The hinge includes two projecting, triangular-shaped, “ears” (auricles). The hinge lacks teeth.  Scallops Shells vary in shape with some being equivalve (both valves have the same shape) and others have a convex right valve and a flat or slightly concave left valve. They may be smooth, cancellate (crisscross ridges)  or sculpted with radial ribs.  These ribs project to the margin, giving the margin a scalloped edge. The right valve has a byssal notch near the auricle. Scallop Shells have valves with different colors, with the left valve being darker than the right valve. The living animals have a row of simple eyes along their mantle with some species having as many as one hundred eyes. Scallop Shells are small to large, with the largest species reaching  21 cm (8.3 inches) in length.

Habitat and Distribution: Scallop Shells reside on hard or soft substrates with the right valve down. Juvenile scallops will often attach themselves to solid substrates via a byssus, while adults are free living.   They can be found in marine and brackish environments. They live in the intertidal zone and to depths exceeding 4,000 m (13,120 feet). Scallop Shells are found worldwide in polar to tropical seas. Twenty-seven species from the Pectinidae Family are found in Mexican waters.

Natural History: Scallop shells are suspension feeders that consume plankton and fine organic matter from the surrounding water. In turn they are preyed upon by crabs, rays, sea stars, fish, shorebirds, and sharks. Scallop Shells may be either gonochoric, protandrous hermaphrodites, or simultaneous hermaphrodites. They reproduce through broadcast spawning with external fertilization. Adult scallops are generally free swimming, moving with a jerky motion, by quickly opening and closing the two valves. This “jet propulsion” utilizes a strong adductor muscle to open and close the valves. Scallop shells have historically been used artistically as religious symbols, fertility symbols, and coats of arms. The adductor muscle of these scallops is the edible and larger species of scallops are commercially fished and farmed.