[2][3][4] Glycymeris longior is a species of dioecious and long-lived clam (there are records of individuals that have reached 69 years).

In the hinge (engagement structure), the valves are articulated by a series of pits (cavities) and triangular teeth (nine on each side).

[4] 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.

[4] This species is found in the Atlantic Ocean, in the southwestern coast of South America, from the state of Espirito Santo, Brazil to the San Matías Gulf in Argentina,[5] with some studies suggesting it might be found up to the northern state of Pará, in Brazil.

[6][7] Glycymeris longior is found buried in or just above sandy soils in shallow waters, up to 10 meters deep.