Fig. 1. (A) Dorsal view of right ulna of Velociraptor IGM 100/981. (B) Detail of red box in (A), with arrows showing six evenly spaced feather quill knobs. In (B), a cast of IGM 100/981 was used. (C) Dorsal view of right ulna of a turkey vulture (Cathartes). (D) Same view of Cathartes as in (C) but with soft tissue dissected to reveal placement of the secondary feathers and greater secondary coverts relative to the quill knobs. (E) Detail of Cathartes, with one quill completely removed to reveal quill knob. (F) Same view as in (E) but with quill reflected to the left to show placement of quill, knob, and follicular ligament. Follicular ligament indicated with arrow.
Abstract: Some nonavian theropod dinosaurs were at least partially covered in feathers or filamentous protofeathers. However, a complete understanding of feather distribution among theropod dinosaurs is limited because feathers are typically preserved only in lagerstätten like that of Solnhofen, Germany or Liaoning, China. Such deposits possess clear taphonomic biases toward small-bodied animals, limiting our knowledge regarding feather presence in larger members of feathered clades.
We present direct evidence of feathers in Velociraptor mongoliensis based on the presence of quill knobs on the posterior forearm. This report of secondaries in a larger-bodied, derived, and clearly flightless member of a nonavian theropod clade represented by feathered relatives is a substantial contribution to our knowledge of the evolution of feathers.
