Pengana robertbolesi, a peculiar bird of prey from the Tertiary of Riversleigh, northwestern Queensland, Australia

Abstract

Pengana robertbolesi, a fossil raptor from the Tertiary of Riversleigh, northwestern Queensland, shares with the living genera Polyboroides and Geranospiza a distinctive morphology of the distal tibiotarsus. The modified structure of the intertarsal joint permits a much greater degree of both anterioposterior and mediolateral flexion than in other species of the Accipitridae. Living species employ acrobatic foraging methods, using the flexible leg to probe hollows and recesses. It is considered that P. robertbolesi used similar foraging techniques. Because it was approximately twice the size of living taxa, it probably was capable of predating substantially larger prey.

Keywords:

• Tertiary
• Riversleigh
• Australia
• Accipitridae
• fossil bird of prey