GAINESVILLE, Fla. --- University of Florida researchers presenting new fossil evidence of an exceptionally well-preserved 55-million-year-old North American mammal have found it shares a common ancestor with rodents and primates, including humans.
The study, scheduled to appear in the Oct. 11 online edition of the Zoological Journal of the Linnean Society, describes the cranial anatomy of the extinct mammal, Labidolemur kayi. High resolution CT scans of the specimens allowed researchers to study minute details in the skull, including bone structures smaller than one-tenth of a millimeter. Similarities in bone features with other mammals show L. kayi's living relatives are rodents, rabbits, flying lemurs, tree shrews and primates.
Researchers said the new information will aide future studies to better understand the origin of primates.
"The specimens are among the only skulls of apatemyids known that aren't squashed completely flat," said study co-author Jonathan Bloch, an associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus. "They're preserved in three dimensions, which allows us to look at the morphology of the bones in a way that we never could before."
Scientists have disputed the relationships of Apatemyidae, the family that includes L. kayi, for more than a century because of their unusual physical characteristics. With can opener-shaped upper front teeth and two unusually long fingers, apatemyids have been compared to a variety of animals, from opossums to woodpeckers.
"There are only a few examples in the history of mammals where you get such an incredibly odd ecological adaptation," Bloch said.
Like a woodpecker's method of feeding, L. kayi used percussive foraging, or tapping on trees, to locate insects. It stood less than a foot tall, was capable of jumping between trees and looked like a squirrel with a couple of really long fingers, si
|Contact: Jon Bloch|
University of Florida