Archaeopteryx compared to its body length. It could reach up to in body length, with an estimated mass of . "Archaeopteryx" feathers, although less documented than its other features, were very similar in structure to modern-day bird feathers. Despite the presence of numerous avian features, "Archaeopteryx" had many non-avian theropod dinosaur characteristics. Unlike modern birds, "Archaeopteryx" had small teeth, as well as a long bony tail, features which "Archaeopteryx" shared with other dinosaurs of the time. Because it displays features common to both birds and non-avian dinosaurs, "Archaeopteryx" has often been considered a link between them. In the 1970s, John Ostrom,
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.