23-16 million years ago, early Miocene.
Flexiraptor was a long-legged bird of prey that hunted and ate small and medium-sized animals such as possums or other mammals, lizards or baby birds.
Special ankle joints allowed Flexiraptor to bend its feet not just forwards, like most birds, but also backwards and sideways, to reach animals hiding in tree hollows and crevices.
The only Flexiraptor fossil known so far is a leg bone (tibiotarsus) with the ankle joint intact, which was found at Riversleigh in north-western Queensland.
Did you know?
Two living hawks bend their feet in a similar way to Flexiraptor. Neither live in Australia nor are they closely related to Flexiraptor. This is an example of convergent evolution - unrelated animals faced with a similar problem independently develop (converge on) the same solution to that problem.