Dinosaur senses primitive birds like "Archaeopteryx" and "Hesperornis". The optic nerve was large in "Carcharodontosaurus". Among dinosaurs, theropods had exceptionally large eyes. Deinonychosaurians, especially troodontids, had forward-facing eyes, suggesting stereoscopic vision and improved depth perception. Tyrannosauroid snouts allowed for a 55˚ binocular field of view, less than a modern human but more than their hadrosaurid prey. Dinosaur senses Dinosaur senses are difficult subjects of study for paleontologists since soft tissue anatomy rarely fossilizes. The three semicircular canals of the inner ear of "Allosaurus fragilis", when viewed from the side, had a subtriangular outline. This subtriangular inner ear configuration is present in "Carcharodontosaurus",
Specimens of Archaeopteryx skeleton of a feathered animal from the same lithographic shale deposits, which would later be known as the London specimen. Coincidentally, von Meyer proposed the name "Archaeopteryx lithographica" for the feather, but not for the skeleton. Therefore, the official name of the animal was originally linked to the single feather rather than any actual skeleton, and is formally considered the original holotype. Though 1860 is often the year named for the feather's discovery, there is no proof of this date, and some authors consider it more likely to have been found in 1861, as it seems reasonable that von Meyer's