Gastornis (pronounced /ɡæˈstɔrnɨs/, meaning "Gaston's bird", formerly known as Diatryma), is an extinct genus of large flightless bird that lived during the late Paleocene and Eocene periods of the Cenozoic. It was named in 1855, after Gaston Planté, who had discovered the first fossils in Argile Plastique formation deposits at Meudon near Paris (France). At that time, Planté (described as a "studious young man full of zeal") was at the start of his academic career, and his remarkable discovery was soon to be overshadowed by his subsequent achievements in physics. In the 1870s, the famous American paleontologist Edward Drinker Cope discovered another, more complete set of fossils in North America, and named them Diatryma (pronounced /ˌdaɪəˈtriːmə/ DYE-ə-TREE-mə, from Ancient Greek διατρέμα, diatrema, meaning "canoe"). The fossil remains of these birds have been found in western-central Europe (England, Belgium, France and Germany) as well as North America. The skull of Gastornis remained unknown except for nondescript fragments, and several bones assigned to it were those of other animals. Thus, the European bird was long reconstructed as a sort of gigantic crane-like ornithuran, very different from the North American species. Eventually this was sorted out, and only then it was realized that Gastornis and Diatryma were so much alike to make most scientists today consider the latter a junior synonym of the former pending a comprehensive review. Consequently the correct scientific name is Gastornis. In fact, this similarity was recognized as early as 1884 by Elliott Coues, but his reasoning was initially discounted and subsequently ignored until the late 20th century. Gastornis were variously considered allied with diverse birds, such as waterfowl, ratites or waders; their highly apomorphic anatomy makes reliable assignment to any one group of birds difficult, in particular since no particularly close relatives survive today. In modern times, they were placed with the "Gruiformes" assemblage. But in the 21st century, these birds are most often considered to be Galloanseres. Quite ironically, the original assessment of Hébert - who perceived similarities with the Anseriformes in the original tibia - thus would be far more correct than any later placement. Incidentially, since the Galloanseres are known to originate in the Cretaceous already, it is comfortably explained how such a gigantic bird could be around less than 10 million years after the non-avian dinosaurs became extinct. "Gastornis" minor is now usually in Remiornis again, at least tentatively. "Diatryma" cotei is a large bird of unclear relationships, possibly a gastornithiform, although it does not seem to belong in Gastornis. "Diatryma filifera" is the name given to fibers erroneously believed to be Gastornis feathers. Finally, some indeterminable gastornithiform remains from the Paleogene of Walbeck (Germany) and the Early Eocene of Park County (USA) may well belong in this genus.r. Gastornis parisiensis measured on average 1.75 metres (5.7 ft) tall, but large individuals grew up to 2 metres (6.6 ft) tall. The Gastornis had a remarkably huge beak with a slightly hooked top, which was taken as evidence suggests that it was carnivorous. Gastornis had large powerful legs, with large, taloned feet, which also were considered in support of the theory that it was a predator. Supposed Gastornis feathers which turned out to be plant material The plumage of Gastornis is unknown; it is generally depicted with a hair-like covering like in ratites, but this is conjectural. Some fibrous strands recovered from a Green River Formation deposit at Roan Creek, Colorado were initially believed to represent Gastornis feathers and named Diatryma. Subsequent examination showed that they were actually not feathers at all but plant fibers or similar.