Glycymeris longior is a species of
dioecious and long-lived clam (there are records of individuals that have reached 69 years). It has
porcelain, subcircular valves (equivalve and equilateral) of brownish color with annual rings. The maximum height of the valves is 50 mm. In the
hinge (engagement structure), the valves are articulated by a series of pits (cavities) and triangular
teeth (nine on each side). The inner edges of the valves are crenulate (festoon or wave-shaped) and, together with the system of teeth and pits, keep the valves aligned. The ligament has striated grooves. Inside the valves you can see the imprints of the
adductor muscles, which are semi-oval and unequal. It has short palps, large
filibranchs, unfused
mantle margins and a large foot, with which it buries itself slowly. It lacks
siphons. The species of this
genus are used in
sclerochronological studies (study of the growth rings of the valves) for environmental reconstructions, given their
longevity, wide geographical distribution, record of environmental variations in their valves and extensive fossil record, among others. == Range ==