International Team Of Scientists Announces The Discovery Of A Remarkably Complete, 47-Million-Year-Old Primate Fossil

Scientists announced in New York the discovery of a 47 million year
old human ancestor. Discovered in Messel Pit, Germany, the fossil,
described
as Darwinius masillae,l is twenty times older than most fossils that
explain human evolution. Known as "Ida," the fossil is a transitional
species
- it shows characteristics from the very primitive non-human evolutionary
line (prosimians, such as lemurs), but is more related to the human
evolutionary line (anthropoids, such as monkeys, apes and humans). At 95%
complete, the fossil provides the most complete understanding of the
paleobiology of any Eocene primate so far discovered. The scientists'
findings are published today in PLoS ONE, the open-access, peer-reviewed
journal from the Public Library of Science.



For the past two years, an international team of scientists, led by
world-renowned Norwegian fossil scientist Dr JГёrn Hurum, University of
Oslo
Natural History Museum, has secretly conducted a detailed forensic
analysis of the extraordinary fossil, studying the data to decode
humankind's
ancient origins. At 95% complete, Ida is set to revolutionize our
understanding of primate evolution.



The fossil was apparently discovered in 1983 by private collectors who
split and eventually sold two parts of the skeleton on separate plates:
the
lesser part (shown in Plate B of Figures 1-2 of the article) was restored
and, in the process, partly fabricated to make it look more complete. This
part was eventually purchased for a private museum in Wyoming, and then
described by one of the authors (Jens L. Franzen) who recognized the
fabrication. The more complete part (plate A of Figs. 1-2) has just come
to light, and it now belongs to the Natural History Museum of the
University of Oslo (Norway). The PLoS ONE paper describes the study that
resulted from finally having access to the complete fossil specimen.



Unlike Lucy and other famous primate fossils found in Africa's Cradle of
Mankind, Ida is a European fossil, preserved in Germany's Messel Pit, the
mile-wide crater and oil-rich shale is a significant site for fossils of
the Eocene Epoch. Fossil analysis reveals that the prehistoric primate was
a
young female. Opposable big toes and nail bearing tips on the fingers and
toes confirm the fossil is a primate, and a foot bone called the talus
bone
links Ida directly to humans.



The fossil also features the complete soft body outline as well as the gut
contents: a herbivore, Ida feasted on fruits, seeds and leaves before she
died. X-rays reveal both baby and adult teeth, and the lack of a
'toothcomb' or a 'grooming claw' which is an attribute of lemurs. The
scientists estimate Ida's age when she died to be approximately nine
months, and she measured approximately three feet in length.
















-- Ida lived 47 million years ago at a critical period in Earth's
history-the Eocene Epoch, a time when the blueprints for modern mammals
were
being established. Following the extinction of dinosaurs, the early
horses, bats, whales and many other creatures including the first primates
thrived
on a subtropical planet. The Earth was just beginning to take the shape
that we know and recognize today - the Himalayas were being formed and
modern flora and fauna evolved. Land mammals, including primates, lived
amid vast jungle.



-- Ida was found to be lacking two of the key anatomical features found in
lemurs: a grooming claw on the second digit of the foot, and a fused row
of teeth in the middle of her lower jaw known as a toothcomb. She has
nails rather than the claw typical of non-anthropoid primates such as
lemurs,
and her teeth are similar to those of monkeys. Her forward facing eyes are
like ours - which would have enabled her fields of vision to overlap,
allowing 3D vision and an ability to judge distance.



-- The fossil's hands show a humanlike opposable thumb. Like all primates,
Ida has five fingers on each hand. Her opposable thumb would have
provided a 'precision grip'. In Ida's case, this is useful for climbing
and gathering fruit; in our case, it allows important human functions
such as making tools, and writing. Ida would have also had flexible arms,
which would have allowed her to use both hands for any task that cannot be
done with one - like grabbing a piece of fruit. Like us, Ida also has
quite short arms and legs.



-- Evidence in the talus bone links Ida to us. The bone has the same shape
as in humans today. Only the human talus is obviously bigger. X-rays and
CT scanning reveal Ida to be about nine months old when she died, and
provide clues to her diet - which included berries and plants. Furthermore
the
lack of a bacculum (penis bone) means that the fossil was definitely
female.



-- X-rays reveal that a broken wrist may have contributed to Ida's death -
her left wrist was healing from a bad fracture. The scientists believe
she was overcome by carbon dioxide gas whilst from drinking from the
Messel lake: the still waters of the lake were often covered by a low
lying
blanket of the gas as a result of the volcanic forces that formed the lake
and which were still active. Hampered by her broken wrist, Ida slipped
into
unconsciousness, was washed into the lake, and sunk to the bottom, where
the unique conditions preserved her for 47 million years.



The full scientific findings from the study are set out in the paper,
Complete primate skeleton from the middle Eocene of Messel in Germany:
morphology and palaeobiology, published by PLoS ONE, the Public Library of
Science's interactive, open-access journal for the communication of
peer-reviewed scientific and medical research. The paper's detailed,
online supporting information is also available to view and download from
the



Citation:

"Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology."
Franzen JL, Gingerich PD, Habersetzer J, Hurum JH, von Koenigswald W, et al. (2009)

PLoS ONE 4(5): e5723. doi:10.1371/journal.pone.0005723

Source
Plos One