A 333-million year old broken bone is causing fossil scientists to reconsider the evolution of land-dwelling vertebrate animals.
Analysis of a fractured and partially healed radius (front-leg bone) from Ossinodus pueri, a large, primitive, four-legged (tetrapod), salamander-like animal, found in Queensland, pushes back the date for the origin of demonstrably terrestrial vertebrates by two million years.
"The break was most plausibly caused by a fall on land because such force would be difficult to achieve with the cushioning effect of water.
"Its age raises the possibility that the first animals to emerge from the water to live on land were large tetrapods in Gondwana in the southern hemisphere, rather than smaller species in Europe.
