A new bird-like dinosaur from the Upper Cretaceous of Mongolia with extremely robust hands supports niche partitioning among velociraptorines

Dromaeosauridae is a clade of bird-like theropod dinosaurs including, among others, the genera <i>Deinonychus</i> and <i>Velociraptor</i>, and characterised by a specialised second toe bearing an enlarged and falciform ungual. Here, we describe an exquisitely-preserved velociraptorine dromaeosaurid from the Upper Cretaceous Djadokhta Formation of Mongolia, and refer it to the new species <i>Shri rapax</i>. This dromaeosaurid is diagnosed by a peculiar combination of vertebral and pelvic features and by an exceptionally robust hand with a very stout pollex bearing the ungual proportionally larger than in any other dromaeosaurid. Combined with cranial adaptations which could support a bite more powerful than in other velociraptorines, the enlarged unguals in both <i>Shri</i> species suggest ecological partitioning in prey preference among the sympatric Djadokhtan dromaeosaurids.