Selected recent studies on marine allenic and acetylenic carotenoids are fo
cused on. The structure elucidation of gyroxanthin, (3S,5R,6S,3'S,5'R,6'R)-
5,6-epoxy-6,7,7',8'-tetradehydro-5',6'-tetrahydro-beta,beta -carotene-3,19,
3',5'-tetrol, is reported in detail and in historical perspective. Gyroxant
hin occurs as a diester (19-dodecanoate 3'-acetate) in the dinoflagellate G
ymnodinium galatheanum. (C) 2000 Elsevier Science Ltd. All rights reserved.