The First Juvenile Dromaeosaurid (Dinosauria: Theropoda) From Arctic Alaska

摘要: Compared to the osteological record of herbivorous dinosaurs from Late Cretaceous Prince Creek Formation northern Alaska, there are relatively fewer remains theropods. The theropod this unit is mostly comprised isolated teeth, and only non-dental known can be attributed troodontid cf. Troodon tyrannosaurid Nanuqsaurus. Thus far, presence members Dromaeosauridae has been limited teeth. Here we describe a symphyseal portion small dentary with two ziphodont Based on tooth shape, denticle morphology, position Meckelian groove, attribute partial saurornitholestine dromaeosaurid. fibrous bone surface, size, higher number mesial denticles compared distal ones point juvenile growth stage for individual. Multivariate comparison teeth morphospace by means principal component analysis reveals an overlap between Saurornitholestinae dromaeosaurid morphospace, result supported phylogenetic analyses. This first confirmed fossil specimen member in Arctic, expanding role Beringia as dispersal route clade Asia North America. Furthermore, nature individual adds growing body data that suggests Arctic Alaska did not undergo long-distance migration, but rather they were year-round residents these paleopolar latitudes.