One day last spring, fossil hunter and anatomy professor Kenneth Rose, Ph.D. was displaying the bones of a jackrabbits 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 years.
Published online in the February Proceedings of the Royal Society, 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 Hopkinss 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 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 didnt know what animal they came from, so we held onto them and figured wed look at them later, he says. It didnt occur to us they would
|Contact: Audrey Huang|
Johns Hopkins Medical Institutions