TRILATIPORATE POLLEN FROM INDIAN PALEOGENE AND NEOGENE SEQUENCES - EVOLUTION, MIGRATION AND CONTINENTAL-DRIFT

The diagnosis of the genus Dorreenipites Biswas, 1962, incorporating h eteropolar pollen with sub-equatorial pores, is emended to include mor phological details observed on pollen recovered from the Miocene ligni te, Neyveli, Tamil Nadu, India. A new genus Retitrilatiporites is prop osed to assimilate trilatiporate pollen from Palaeocene-Eocene sedimen ts of Kutch, which are distinct in having feeble pore-bearing projecti ons, +/- equatorial pores, and a smaller size. A speciation scheme for both trilatiporate genera is proposed based on significant morphologi cal features, namely well-developed vs. feeble pore-bearing projection s, and exine structure varying from psilate to reticulate on one or bo th poles. Evolutionary trends of these taxa in Africa and India and th eir stratigraphic significance are discussed, from the perspective of their migration and extinction, which was controlled by the northward drift of the Indian plate. Four new species and five new combinations are proposed, and the botanical relationship of this pollen type is di scussed.