The paper was the culmination of "a lot of work," that stretched over many years, Li said.

    The skull and jawbones were wrapped inside a small lump of stone, no more than a few inches in diameter.

    It was tucked between other stones on a hill in rural Hengyang, in Central China's Hunan Province.

    For palaeontologists -- researchers who look for fossils and study extinct animals and plants -- the rolling small hills, in what they call the Hengyang basin of red earth, are a palaeontological haven.

    The area was first discovered by Yang Zhongjian (Young Chung-Chien), one of the pioneering Chinese palaeontologists, as early as the 1930s.

    In the basin of what he called the "red beds of Hunan," Yang discovered one lower tooth of a horse-like animal in 1937, and published his find on the journal American Museum Novitates.

    But casual passers-by and local farmers see only the farm fields and red hills.

    However, trained eyes plus professional instincts have enabled researchers to pick and dig from the outcrop interesting finds that help them piece together the puzzles of the earth's past.

    Since the founding of New China in 1949, Chinese palaeontologists have made numerous research surveys in the area and found fossil skulls, bones and teeth belonging to 20-plus animals that lived millions of years ago.

    Among them were horses, rodents, lizards and alligators.

    Hu Yaoming was the researcher who found the fossil.

    Hu is currently working at the Division of Paleontology of the American Museum of Natural History.

    Li said it took Xie Shuhua, a chief technician at the institute, two years to prepare the fossil skull and its teeth from the small lump of stone.

    The analytical work took nearly three more years.

    Their analysis indicated the small ancient primate mainly moved about during the day. So, the species was diurnal.

    "That's not at all what I expected," Richard F. Kay of Duke University Medical Center in Durham, North Caroline, was quoted by the American Association for the Advancement of Science as saying.

    The finding suggests that the first primate ancestor may have been diurnal, too, according to Kay.

    Robert Martin, from the Field Museum in Chicago, however, notes that the skull has a large opening on the snout for the nerve connected to the whiskers, which tended to be more developed in nocturnal mammals.

    The Chinese researchers stressed their finding only pointed to one possibility and was not conclusive.

    Ni said they had followed strict professional practices during their analytical work.

    The researchers examined and compared the data of 303 dental, cranial, post cranial and soft tissue characters and 52 taxa, or classified groups of mammals.

    "The work was arduous, as there were tons of data," Ni recalled. "We couldn't afford to miss any clue that revealed the evolution of the ancient primates from the existing fossils."

    Thus, Chris Beard of the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, commented that the new discovery that the earliest modern primates had small eyes turns the traditional view of primate evolution "on its head," according to Nature magazine.

    What lies ahead?

    Whatever the argument, their findings have laid the foundation for further research into the "many unknowns."

    For example, Li said it has been widely believed mammals couldn't travel between Asia and Europe around 55 million years ago.

    The landmass of Eurasia was thought to be "largely or completely split down the middle by a combination of the Western Siberian Obik Sea to the north and the Turgai Straits to the south," Martin noted.

    However, the Teilhardina asiatica found in China, which shares so many features with its cousins in Europe, suggests it was possible for mammals to trek across Eurasia in those days.

    "Abundant fossils of earlier primates found in China indicate Asia was an important platform for the euprimates to appear and evolve," Ni wrote two years ago in the team's application for research funding to the National Natural Science Foundation of China.

    The researchers' job now is to link the Chinese fossils together, and then to link them with their cousins found in other places in Asia as well as in Europe and North America.

    ¡¡(China Daily)