leptecodon (meaning "small tooth") is a genus of prehistoric mackerel-like ray-finned fish which was described by williston in 1899 and was possibly preyed on by other sea creatures. however, it was a hunter of smaller creatures itself. this fish sometimes hid in clams such as "inoceramus". the first-discovered fossil was inside a clam. many believe that "leptecodon" had formed a symbiotic relationship with the clam rather than get eaten by "inoceramus". another fish from the same time and place, "caproberyx", has also been found among "inoceramus.