to the strength. The foot is strongly arctometatarsalian, with the third metatarsal excluded from the front surface of the metatarsus over 40% of its upper length. Phylogeny Anserimimus was by Barsbold assigned to the Ornithomimidae, a group of derived Ornithomimosauria. This has been confirmed by modern cladistic analysis. Its closest relative may be Gallimimus from the same formation albeit from a different area (Kobayashi & Lu, 2003; Kobayashi & Barsbold, 2005). Other studies have been unable specifically to determine its relationships or those of any other ornithomimids (Ji et al., 2003; Makovicky et al., 2004). The following cladogram is based on Xu et al., 2011: Paleobiology The function of the powerful arm, with its straightened claws, remains unknown. It may indicate a different diet of food-gathering strategy than other ornithomimids, although its diet is difficult to determine, since the animal's skull is unknown. Scientists have long hypothesized that ornithomimids, descended from carnivorous theropod ancestors, were actually omnivores or even herbivores. Paleoecology Anserimimus was recovered from the Nemegt Formation of Mongolia. The Nemegt is thought to represent alluvial plains containing meandering rivers. The layer Anserimimus was found, is dating from the early Maastrichtian stage of the Late Cretaceous, or about 70 million years ago. Aside from Gallimimus, other theropods found in the Nemegt Formation include the gigantic Tarbosaurus and Deinocheirus, as well as smaller dromaeosaurids, oviraptorosaurs, troodontids, and birds. Herbivores are represented by the hadrosaurids Barsboldia and Saurolophus, the ankylosaurid Tarchia and several titanosaurian sauropods and pachycephalosaurians. The rock facies of this formation suggest the presence of stream and river channels, mudflats, and shallow lakes. Sediments also indicate that there existed a rich habitat, offering diverse food in abundant amounts that could sustain massive Cretaceous dinosaurs. See also Timeline of ornithomimosaur research References External links Anserimimus at The Theropod Database Late Cretaceous dinosaurs of Asia Fossil taxa described in 1988 Ornithomimids Taxa named by Rinchen Barsbold Maastrichtian life Nemegt fauna