items like plants, forams, mollusks, and ostracods from the water. The authors further noted that ornithomimids were abundant in mesic environments, and rarer in more arid environments, suggesting that they may have depended on waterborne sources of food, possibly filter feeding. They noted that primitive ornithomimids had well developed teeth, while derived forms were edentulous and probably could not feed on large animals. One later paper questioned the conclusions of Norell et al. Barrett (2005) noted that vertical ridges are seen on the inner surface of the beaks of strictly herbivorous turtles, and also the hadrosaurid Edmontosaurus. Barrett also offered calculations, estimating how much energy could be derived from filter feeding and the probable energy needs of an animal as big as Gallimimus. He concluded that herbivory was more likely. Classification Named by O.C. Marsh in 1890, the family Ornithomimidae was originally classified as a group of ornithopods. Two years later, Marsh described additional material and realized that ornithomimids were theropods. As relationships within theropods began to be resolved in the 20th century, Friedrich von Huene included Ornithomimidae in his infraorder Coelurosauria. Recognizing the distinctiveness of ornithomimids compared to other coelurosaurs, Rinchen Barsbold placed ornithomimids within their own infraorder, Ornithomimosauria, in 1976. Today, Ornithomimosauria is regarded as a clade within Coelurosauria. The contents of Ornithomimidae and Ornithomimosauria varied from author to author as cladistic definitions began to appear for the groups in the 1990s and 2000s. The cladogram below was the result of a study conducted in 2015 by Claudia Serrano-Branas and colleagues. See also Timeline of ornithomimosaur research References Ornithomimosaurs Turonian first appearances Maastrichtian extinctions Taxa named by Othniel Charles Marsh Prehistoric dinosaur families