Prasad Mahesh, Khare E G, Kannaujia A K
Birbal Sahni Institute of Palaeobotany, Lucknow-226 007, India.
Department of Botany, Lucknow University, Lucknow-226 007, India.
J Environ Biol. 2013 Sep;34(5):863-75.
A variety of fossil leaves were collected from the Siwalik group of India and Nepal. Few of them possessing sufficient cuticle were identified on the basis of morphological and cuticular features (epidermal cells, stomatal density, stomatal index etc). They closely resembled with the extant taxa, Pterospermum acerifolium (Sterculiaceae), Dichapetolum gelonioides (Dichapetalaceae), Paranephelium mocrophyllum, P. xestophyllum (Sapindaceae), Gluto renghos (Anacardiaceae) and Mimusops elengi (Sapotaceae). The habit, habitat and present day distribution of the above modern comparable taxa suggest the prevalence of tropical humid environment during deposition of Siwalik sediments in the Sub-Himalayan zone. The extinction of the above comparable taxa (except Pterospermum acerifolium) from the Sub-Himalayan zone indicates the environmental change after Mio- Pliocene time. The epidermal and stomatal features of the fossil leaves collectively suggest the existence of a broad leaved mesophytic forest at low altitude having comparatively high humidity all along the Himalayan foot hills during 8-12 million years ago.
