Pure and Applied Chemistry

Abstract: Four stereochemical series of diastereomeric polyhalogenated chamigrane sesquiterpenes -headed by obtusol, isoobtusol, rogiolol, and cartilagineol- suggest the existence of four lineages of red seaweeds in the genus Laurencia.On another front, concerning marine ciliates, euplotane sesquiterpenes characterize worldwide the morphospecies Euplotes crassus, well differentiated from Euplotes raikov, Euplotes rariseta, and Euplotes vannus, which furnish different-skeleton sesquiterpenoids, and the latter also C₃₀-backbone isoprenoids. The latter three morphospecies, however, show polymorphism in the variability of their isoprenoids.