[Taxacom] 53 million year rabbit foot
jgrehan at sciencebuff.org
Fri Nov 18 15:39:32 CST 2011
Here's a recent example of an older fossil predating the molecular date.
Note their comment that " previous fossil and molecular data suggested
that rabbits and hares diverged about 35 million years ago".
Good Luck Indeed: 53 Million-Year-Old Rabbit's Foot Bones Found
One day last spring, fossil hunter and anatomy professor Kenneth Rose,
Ph.D. was displaying the bones of a jackrabbit's foot as part of a
seminar at the Johns Hopkins University School of Medicine when
something about the shape of the bones looked oddly familiar.
That unanticipated eureka moment has led researchers at the school to
the discovery of the oldest known record of rabbits. The fossil evidence
in hand, found in west-central India, predates the oldest previously
known rabbits by several million years and extends the record of the
whole category of the animal on the Indian subcontinent by 35 million
Published online in the February Proceedings of the Royal Society
<http://royalsociety.org/> , the investigators say previous fossil and
molecular data suggested that rabbits and hares diverged about 35
million years ago from pikas, a mousy looking member of the family
Ochotonidae in the order of lagomorphs, which also includes all of the
family Leporidae encompassing rabbits and hares.
But the team led by Johns Hopkins's Rose found that their rabbit bones
were very similar in characteristics to previously unreported Chinese
rabbit fossils that date to the Middle Eocene epoch, about 48 million
years ago. The Indian fossils, dating from about 53 million years ago,
appear to show advanced rabbit-like features, according to Rose.
"What we have suggests that diversification among the Lagamorpha
group-all modern day hares, rabbits and pikas-may already have started
by the Early Eocene," says Rose, professor in the Center for Functional
Anatomy and Evolution <http://www.hopkinsmedicine.org/fae/index.html>
at the Johns Hopkins University School of Medicine.
Rose says the new discovery was delayed a few years because the
researchers had not been looking specifically to determine the age of
rabbits. "We found these bones on a dig in India a few years ago and
didn't know what animal they came from, so we held onto them and figured
we'd look at them later," he says. "It didn't occur to us they would be
rabbits because there were no known rabbits that early in time and the
only known rabbits from that part of the world are from central Asia."
But one day, while using the jackrabbit foot bones as a teaching tool
for a class, the shape of the bones in the class struck him as something
he'd seen before among his collection of unidentified bones.
Sure enough, the tiny bones about a quarter of an inch long from India
looked remarkably similar to ankle and foot bones from modern day
jackrabbits, which are 4 to 5 times bigger.
Rose and his team set out and measured every dimension of their Indian
bones and compared them to eight living species of rabbits and hares.
They also compared them to two species of the related pika-that
mouse-like, mountain-dwelling critter that lives in the Rocky Mountains
of North America, among other places.
Using a technique called character analysis, the team first recorded
measurements of 20 anatomical features of the bones, which showed that
the bones are definitely Lagomorph and closer to rabbits than pikas. The
scientists then ran a series of statistical tests on the individual
measurements to see how they compared with the Chinese fossils as well
as living rabbits and pikas. They found that although the Indian fossils
resemble pikas in some primitive features, they look more like rabbits
in specialized bone features.
Asked how many years of good luck one gets with a 53 million-year-old
rabbit foot bone, Rose quipped that he "already got lucky with the feet,
but what we really would like are some teeth that tell how different
these animals really were."
The research was funded by the National Geographic Society, Department
of Science and Technology, Government of India, the Council for
Scientific and Industrial Research of India, the Research Foundation
Flanders and the Belgian Federal Science Policy Office.
Authors on the paper are Valerie Burke DeLeon and Rose of Hopkins;
Pieter Missiaen of University of Ghent, Belgium; R.S. Rana and Lachham
Singh of H.N.B. Garhwal University in Uttaranchal, India; Ashok Sahni of
Panjab University, India; and Thierry Smith of the Royal Belgian
Institute of Natural Sciences in Brussels, Belgium.
Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193
email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723
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