File  Shells of the Limidae Family

Two File Shells of the Limidae Family can be found in this website:

Phylogeny: File Shells of the Limidae Family are bivalve mollusks in the Limida order. Limids are characterized by their elongate, ribbed, shells. Limoidea is the only superfamily in this order and the Limidae Family is the only family within Limoidea. The Limidae Family contains one subfamily – Liminae, which contains the genus Mantellina and one species. The Family Limidae also contains nine stand alone genera – Acesta with twenty-nine species, Acestarica with one species, Ctenoides with fifteen species, Divarilima with six species, Escalima with three species,  Lima with twenty-four species, Limaria with thirty-five species, Limatula with seventy-eight species, and Limea with twenty-two species. These shells are also commonly known as File Clams and Flame Clams.

Description: Files Shells are medium to large-sized shells, which vary from ovate to trigonal in outline. They are equivalve and only slightly inflated. They have a straight hinge which may project slightly as auricles (ears), especially on the posterior. The hinge lacks teeth. There is a gap between valves at the top front of the shell. The shell’s outer surface may be smooth, ribbed, or scaly. If the ribs extend to the margin, the interior will have a serrated edge. These shell are generally white in color and have a thin periostracum. The living animal is usually a bright red or orange, with tentacles attached to the mantle. Larger species of File Shells can exceed 20 cm (7.8 inches) in height. File Shells can be similar in appearance to Scallop Shells of the Pectinidae Family, but are more obliquely ovate in shape, with less pronounced auricles (ears) or only one pronounced auricle.

Habitat and Distribution: File Shells can be free swimming and therefore can be found in a variety of habitats. Some are found on soft sand or mud substrates, some hide in rock crevasses or under rubble, some hide in seagrasses, some attach to hard surfaces by use of byssus, and some nestle in a nest of byssus. They are found in protected estuaries and bays, exposed coastlines, and deep waters. They live in the intertidal zone, and to a depth of 1,097 m (3,600 feet). They are found worldwide in polar to tropical waters. Seven species of File Shells are found in Mexican waters.

Natural History: File Shells are suspension feeders that filter plankton and fine detritus from the surrounding water. File Shells can swim, like scallops, by quickly opening and closing their valves to produce a jet of water. Their defensive mechanisms include their hard shells, their hiding under sand or in crevasses, swimming to escape, and the ability to shed their tentacles, which continue to wiggle and thereby distract predators. They are preyed upon by birds, crabs, fish, carnivorous mollusks and sea stars. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. File Shells are edible and larger species have been the target of fisheries but only to a minor extent.