Fossil leaf impressions from Siwalik sediments of Himalayan foot hills of Uttaranchal, India and their significance

Abstract

Morphotaxonomical study of well preserved angiospermous leaf impressions collected from Siwalik sediments of Purniyagiri near Tanakpur, Uttaranchal records five species viz., Mitrephora siwalika Antal & Awasthi, Sterculia tertiara sp. nov., Millettia purniyagiriensis sp. nov., Cynometra siwalika Awasthi & Prasad and Chonemorpha miocenica Prasad & Awasthi. These species compare with the extant taxa Mitrephora maingayi (Anonaceae), Sterculia ensifolia (Sterculiaceae), Millettia auriculata, Cynometra polyandra (Fabaceae) and Chonemorpha macrophylla (Apocynaceae) respectively. The habit, habitat and the present day distribution of the comparable extant taxa indicate that tropical evergreen forest was flourishing under warm humid climate in the area during the Siwalik times as compared to mixed deciduous forest there at present.