A 260-million-year-old fossil is the oldest known tree-dwelling creature, according to researchers. Scientists described the finding as the earliest evidence in the fossil record of an "opposable thumb"... they described how the animal's elongated hands and fingers would have helped it to grip and climb... The fossilised creature, named Suminia getmanovi, has been dated to late Permian period, 100 million years earlier than the first known tree-dwelling mammal. It was first discovered in Russia in 1994. But for lead author Jorg Frobisch, from the Field Museum in Chicago, US, said this study was the first opportunity to examine its whole...