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",
Most recent common ancestor all of the modern population. Due to pedigree collapse, modern individuals may still exhibit clustering, due to vastly different contributions from each of ancestral population . Most recent common ancestor In biology and genealogy, the most recent common ancestor (MRCA, also last common ancestor (LCA), or concestor) of any set of organisms is the most recent individual from which all the organisms are directly descended. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree.