 The discovery of partial diplodocid skin impressions in 1990 showed that some species had narrow, pointed keratinous spines, much like those on an iguana and up to 18 centimetres (7.1 in) long, on the "whiplash" portion of their tails, and possibly along the back and neck as well, as in hadrosaurids. The spines have been incorporated into many recent reconstructions of Diplodocus, notably Walking with Dinosaurs. However, the original description of the spines noted that the specimens in the Howe Quarry near Shell, Wyoming were associated with skeletal remains of an undescribed diplodocids "resembling Diplodocus and Barosaurus." Specimens from this quarry have since been referred to Kaatedocus siberi and Barosaurus sp., rather than Diplodocus.
