Abstract
Depot fat from the Atlantic leatherback turtle (Dermochelys coriacea coriaceaL.) was shown to contain ≈3% oftrans‐6‐hexadecenoic acid. Structural details were elucidated through comparative aspects of isolation techniques, NMR, IR, hydrogenation, oxidative fission, etc., and confirmed by similarity of properties with those of a sample of fatty acid of this structure isolated from the seed oil ofPicramnia sellowii. One additional leather‐back turtle oil sample, and depot fat from two other marine turtles, the loggerhead (Caretta caretta caretta) and ridley (Lepidochelys olivacea kempi) contained this acid, that from the ridley in a lower proportion. No corresponding C18acid was detected in the leatherback oil.