Gastornis: A Giant Flightless Bird Found in Ypresian Eocene Paleogene Europe (as well as NorAm)

The birds (Aves) from the Early Eocene of La Borie, southern France

Authors:

Bourdon et al

Abstract:

The Early Eocene locality of La Borie is located in the village of Saint-Papoul, in southern France. These Eocene fluvio-lacustrine clay deposits have yielded numerous vertebrate remains. Mammalian taxa found in the fossiliferous levels indicate an age near the reference level MP 8–9, which corresponds to the middle Ypresian, Lower Eocene. Here we provide a detailed description of the avian remains that were preliminarily reported in a recent study of the vertebrate fauna from La Borie. A maxilla, a quadrate, cervical vertebrae, a femur and two tibiotarsi are assigned to the giant ground bird Gastornis parisiensis Hébert, 1855 (Gastornithidae). These new avian remains add to the fossil record of Gastornis, which is known from the Upper Paleocene to Middle Eocene of Europe, Early Eocene of Asia, and Early Eocene of North America. Gastornis parisiensis differs from the North American Gastornis giganteus (Cope, 1876) in several features, including the more ventral position of the external nares and the slender orbital process of quadrate. Two tibiotarsi and one tarsometatarsus are assigned to a new genus and species of Geranoididae, Galligeranoides boriensis gen. nov, sp. nov. So far, this family was known only from the Early and Middle Eocene of North America. The fossils from La Borie constitute the first record of the Geranoididae in Europe. We show that Gastornis coexisted with the Geranoididae in the Lower Eocene of both Europe (La Borie) and North America (Willwood formation). The presence of Geranoididae and the large flightless bird Gastornis on either side of the present-day North Atlantic provides further evidence that a high-latitude land connection existed between Europe and North America in the Early Eocene.