9 mln-yr old teeth from Pakistan reveal variation in vegetation on ancient sub-Himalayan plain

February 4th, 2009 - 3:13 pm ICT by ANI  

Washington, Feb 4 (ANI): A team of scientists has used stable carbon isotope ratios measured in 9-million-year-old mammalian tooth enamel from northern Pakistan to reveal how the landscape and vegetation varied across two different paleo-river systems on the ancient sub-Himalayan plain.

The team was led by Michele E. Morgan from the Peabody Museum, Harvard University, in the US.

The teeth were sampled along a 32-km transect within a time slice of about 150,000 years.

Fossil teeth from the southwestern end have more of the heavier 13-C isotope compared with fossil teeth from the northeastern end, evidence that there was increased evaporation of moisture from the soil and plants in that direction.

The carbon isotopic data indicate that animals living on the river plain to the southwest were foraging in more open vegetation compared with the river system to the northeast, which had moister soil conditions with more closed-canopy woodland and forest.

The data also imples that the resident mammals, including giraffes, antelopes, pigs, the hippo-like anthracotheres, and primates, stayed in a limited area and did not move from one river system to the other on a yearly or seasonal basis.

This approach offers new insights into kilometer-scale habitat variation and mammalian landscape-use patterns in an ancient sub-Himalayan ecosystem.

Through such analyses of carbon atoms preserved in fossils, paleontologists and chemists are opening new windows onto Earths ecological past. (ANI)

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