Referred Species: G. parisiensis, G. gigantea, G. sarasini, G. geiselensis, G. russeli, G. xichuanensis
My third favorite extinct Avialan!
Gastornis is a fairly famous genus of extinct Neornithean due to its role on the popular documentary, Walking with Prehistoric Beasts. Sadly, since that documentary came out we have learned a lot about this bird, much of which contradicts its depiction in that film. It lived in the Paleocene and Eocene epochs of the Paleogene period, specifically from the Thanetian to Lutetian ages, from about 56 to 45 million years ago. It had a very large range, across western Europe, the United States, and china, and it was one of the largest animals found in its ecosystems. It originated in Europe and probably radiated out through the Bering Land Bridge to other locations, though the genus lasted longer in Europe as well due to the isolation of the continent.
Though the North American species were formerly known under the genus Diatryma, they were eventually lumped in with Gastornis after extensive study. In cladistic analyses it has been found to be a kind of Anseriform, the group that includes ducks and their close relatives like geese and screamers; indicating that it was basically a large, strange land duck. As such, though it used to often be reproduced with ratite-like plumage due to its large size, however fossil discoveries have been found that might belong to Gastornis with vaned, broad feathers like that of flighted birds – the feathers themselves were large and probably belonged to something like Gastornis or close to its size, and given its phylogenetic position the presence of vaned broad feathers seems likely. It was a large bird, about 2 meters in height, with a powerfully built and very large skull, with a very tall and flattened beak. It had very small, reduced wings, due to its flightless niche.
Now, despite what Walking With Beasts may have told you, Gastornis has recently been found to actually be an herbivore, rather than a large carnivore. There is no chemical evidence that it had meat in its diet, as based on calcium isotope studies in the bones. This chemical analysis revealed that Gastornis’s diet was most similar to other herbivorous dinosaurs, rather than Tyrannosaurus or the terror birds. It also coexisted with other large mammals like pantodonts, so the cause of this animal’s extinction is relatively unknown. Eggs and footprints are known from the genus (and have been covered here on this blog), however, some of the fossil footprints known are much younger than fossils known from Gastornis, indicating that it or its relatives lived longer than previously thought. However, it is entirely likely that these prints were made by later relatives of Gastornis, rather than Gastornis itself.
Plot Designing 