Plant biodiversity in the Mahanadi Basin, India, during the Gondwana period

The Mahanadi Basin is one of five major sedimentary basins of Peninsular In dia and is situated on the east coast. The sediments are exposed in two dif ferent regions: an extensive basin comprising Lower to Upper Gondwana with coal measures towards the west (Talchir and Ib-River Sub-basins); and the A thgarh Sub-basin in the east with rocks of only Upper Gondwana age. This study is mainly concerned with plant species diversification and the d evelopment of flora in the Mahanadi Basin from the Early Permian to the Ear ly Cretaceous. A number of successive megafloras are recognised with gaps i n the sequence. A few animal records are also considered in order to examin e biodiversity in the basin. Leaves are the dominant part of the preserved flora, followed by fruits. No stem or wood parts are preserved and the root parts are represented by the form genus Vertebraria. Pre-angiosperm fossil floras at species level are plotted systematically in Table 2 to examine t he plant diversity through different geological formations in the Mahanadi Basin. Maximum plant diversification in gymnosperms is recorded in the Late Permian (Kamthi Formation), and in pteridophytes in the Early Cretaceous ( Athgarh Formation). (C) 2000 Elsevier Science Limited. All rights reserved.