The ultrastructure of cerebropollenites from the jurassic and cretaceous of asia

The dispersed pollen taxon Cerebropollenites recovered from the Jurassic of Afghanistan and Cretaceous of China was investigated ultrastructurally. Cerebropollenites lacks the differentiation of the proximal and distal hemispheres, a faint proximal triradiate mark, and an equatorial fringe, all features found in extant Tsuga, however, the gross pollen morphology, and the wall ultrastructure of Cerebropollenites suggests an affinity with the extant genus Tsuga (Section Micropeuce). The differences observed between Cerebropollenites and Tsuga are no greater than the differences observed between the pollen of the two Sections of Tsuga, Hesperopeuce and Micropeuce. The occurrence of Cerebropollenites in the Jurassic and Cretaceous is, thus far, the only fossil evidence that the genus Tsuga may have been present in the Mesozoic, and suggests that the Pinaceae, which is unequivocally recognized in the Cretaceous, may have had an earlier origin.