A C4 plant from the Pliocene

The Origin of Grass-Dominated Ecosystems

“…Dots indicate data from specific, well-constrained times. Sources: (1) Crepet & Feldman (1991), (2) Thomasson (1990), (3) Thomasson et al (1986), (4) Nambudiri et al (1978), (5) MacGinitie (1962), (6) Thomasson et al (1990) (1994), (17) Jernvall et al (1996). region, only one grass species is recognized based on macrofossils (Elias, 1942). Macrofloras document the emergence of grass-dominated environments between 13 and 10 Ma (MacGinitie, 1962;Thomasson, 1990).…”

“…By 7 Ma grass diversity includes all five living subfamilies (Thomasson, 1990). Leaf anatomical evidence for C4 photosynthesis is documented by 12.5 Ma (Nambudiri et al, 1978;Whistler & Burbank, 1992).…”

Evolutionary History of the Grasses

“…Studies of ancient ecosystems have shown that these broad areas developed 5 to 6 million years ago. The earliest record of C 4 photosynthesis is based on isotopic ratios and is dated at 15 million years ago (Kingston et al, 1994;Latorre et al, 1997), and the earliest leaf fragment that can be confidently designated C 4 is dated at 12.5 million years ago (Nambudiri et al, 1978).…”

Carbon isotopic composition of fossil leaves from the Early Cretaceous sediments of western India

“…Plant mega-fossil representing a single species does not suffer from such limitations. It is also well established that the fossil plants typically retain their isotopic compositions (Degens 1969;Nambudiri et al 1978;Rigby et al 1981;Aucourt and Hillaire-Marcel 1993;Bocherens and Marootti 1998). So it is quite likely that the analysis of fossil plants from the Indian subcontinent would be useful in enhancing our understanding of the ancient atmospheric compositions, since carbon fixed by land plants reflects carbon isotopic fluctuations of atmospheric CO 2 , and consequently, the isotopic behaviour of the ocean-atmosphere system (Hasegawa et al 2003).…”