A chicken-sized crane precursor from the early Oligocene of France.

A skeleton of a chicken-sized crane precursor is described from the Lower Oligocene of the Lubéron in Southern France. Parvigrus pohli gen. et sp. nov. is the most substantial Paleogene fossil record of the Grues (Aramidae [limpkin] + Gruidae [cranes]), and among its oldest representatives. The fossil species is classified in the new taxon Parvigruidae, which is shown to be the sister group of extant Grues. It is the first fossil record of a stem lineage representative of the Grues and, among others, differs from modern Grues in its smaller size, shorter beak, and rail-like limb proportions. Size increase in the stem lineage of the Gruidae may be related to the spread of grasslands during the Oligocene and Miocene. Occurrence of stem lineage Grues in the Lower Oligocene of Europe is in concordance with the fact that there is no evidence for the presence of crown group members of modern avian "families" in pre-Oligocene fossil deposits.