Fossil Shows Placental Mammals 35 Million Years Earlier


“The earliest known eutherian from the Jurassic of China.” Source of caption and photo: online version of the NYT article quoted and cited below.

(p. D3) The split between placental mammals and marsupials may have occurred 35 million years earlier than previously thought, according to a new study.
. . .
The newly identified mammal was small, weighing less than a chipmunk. Based on its claws, it appears to have been an active climber. “This was a skinny little animal, eating insects,” said Dr. Luo. “We imagine it was active in the night and capable of going up and down trees.”
Its discovery helps reconcile fossil evidence and molecular analysis. Modern molecular studies, which use DNA to estimate dates of evolution, also put the emergence of placentals at about 160 million years ago.

For the full story, see:
SINDYA N. BHANOO. “OBSERVATORY; A Small Mammal Fossil Tells a Jurassic Tale.” The New York Times (Tues., August 30, 2011): D3.
(Note: ellipsis added.)
(Note: the online version of the article is dated August 24 (sic), 2011.)

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