The name may reflect the condition of the specimen: some of the bones were partially crushed (typical for Niobrara fossils and a detail Marsh does not mention) and most of the skull was missing. Marsh considered the dinosaur's solid limb bones diagnostic (Hadrosaurus had hollow limb bones), and later identified well preserved fossils of a large Lance hadrosaur (now Edmontosaurus) as "Claosaurus" as well. He gave the new form the species name annectens (a-NEK-tenz) "intermediate, transitional" (literally Latin for "connecting together"), alluding to its limbs, which combined features of both bipeds and quadrupeds (including a hoofed manus), and thus "linked" the limb structure of Camptosaurus and Stegosaurus.