Earliest primate had tree-climber ankles
A creature known only from fossils of its teeth gets some more parts
By Susan Milius
RALEIGH, N.C. — Finally, the earliest known primate has more than a mouth. Several 65-million-year-old fossil ankle bones found among unsorted bits from excavations in Montana belong to a tree-dwelling species of Purgatorius, Stephen Chester of Yale University announced October 19 at the annual meeting of the Society of Vertebrate Paleontology.
The first signs that Purgatorius existed came from fossil teeth unearthed nearly half a century ago at an excavation site in northeastern Montana not far from where the first Tyrannosaurus rex was found. Paleontologists named two species of what they called Purgatorius. William Clemens of the University California Museum of Paleontology and his colleagues described more teeth and some bits of mouth bones since then, but nothing had turned up from the rest of the body.
“The teeth were so primitive we didn’t know much,” said Ken Rose of Johns Hopkins University School of Medicine in Baltimore, who heard the presentation at the meeting. Several lineages diverged early in the history of primates, and sorting out their relationships has been tricky.