Closest relatives of Primates Earliest true primates share: • Archonta • Inner ear morphology – Scandentia (tree shrews) • Postorbital bar, orbital convergence – Dermoptera (flying lemurs) • Large brain case with large orbits – Chiroptera (bats) • Modifications of the elbow • Plesiadapiformes • Elongation of the heel, opposable thumb – Paleocene radiation of unusual critters and nails (instead of claws) – Replaced by rodents – Put in and out of Primate order Eocene Oligocene • Lots of fossils from N America and Europe; little • Continents mostly in present positions from Africa or Asia; • S America and Australia separate from • Prosimians anatomically and likely behaviorally Antarctica • Adapoids and Omomyoids, ecologically diverse; • Best site is Fayum, Egypt 28-32 my very similar early so likely monophyly Lemurs, Lorises • Adapoids like higher primates with large size, • , early anthropoid primates diurnality, frugivory and folivory (feet like lemurs) • Propliopithecus and Aegyptopithecus • Omomyoids more similar to galagos but • Dental apes but New World monkey bodies increase in size and folivorous late • Late Oligocene settling of S. America by • Where are prosimians lately? anthropoid primates Relationships based on fossils and Monkey Evolution molecular evidence • Hominoid and cercopithecoid apomorphies • New World Monkeys (Platyrrhini) show up in Oligocene, primitive versions by Miocene and at 20 and 18 my thereafter look very much like modern forms • Gibbons and Siamangs at 17 my • Old World Monkeys (Catarrhini) show up in Miocene (after apes); Victoriapithecus and then • Orang utans at 12 my split between colobines and cercopithecines; lots of evolutionary change late and lots of • Gorillas at 9 my convergences make systematics challenging • Pan troglodytes and Pan paniscus at 6 my • Also absence of fossils from many lineages • Very successful lately; out competing most apes • Putting chimp vs. human at 4.5-7 my due to their greater success with folivory and tolerance to plant protective chemicals 1 Miocene apes Miocene con’t. • 25-5 my; temperatures increase • Early Miocene African representatives from East • Increasing aridity Africa; by 15-8 my all over Eurasia too thanks to • Tethys Sea changes availability of Arabian peninsula • Arabian peninsula • All post-early Miocene hominoids likely evolved • E African rift system from thick enameled hominoid before migration • Lots of primitive hominoids and “apes” that are more to Eurasia about 16.5 my advanced than Oligocene forms • Sivapithecines ancestral to orang utans • Huge range in size and found in lots of settings • Apes more common in early Miocene, monkeys more • Common of later hominoids would have robust common in late Miocene masticatory apparatus with suspensory • Most successful apes in late Miocene adapted to dry positional behavior conditions with thick enamel and found in open habitats • Exploited many niches Pliocene (5-1 my) Highlights • Late Miocene (8-5 my): diversification of the African apes • Sample is restricted geographically to dryer conditions excepting material from Chad • Bipedalism develops in late Miocene to early Pliocene hominins (6-4 my) • Rich samples of Australopithecus • Adaptive radiation of African hominins between 4 and afarensis and A. africanus but most 1.7 my specimens are fragmentary and • 1.7 my to present, now Homo (initially Homo erectus) associated partial skeletons rare bigger brain coupled with explosive expansion out of Africa • Postcrania (neck down anatomy) can’t be • Reduction in genera and later in species? associated with taxa between 2.7 and 1.2 • Eventually one line that replaces all others? Neandertals my definitely replaced by African invaders in “second wave” Recommended Web Sites Becoming Human by Institute for Human Origins, Arizona State University http://www.becominghuman.org/ Fossil Hominids: The Evidence for Human Evolution in the Talk Origins Archive http://www.talkorigins.org.faqs/homs/ The Human Origins Program at the Smithsonian Institution http://www.mnh.si.edu/anthro/humanorigins/ The Hominid Journey by Richard Effland and Ken Costello, Dept. of Anthropology, Mesa Community College, Mesa, AZ http://www.mc.maricopa.edu/~reffland/anthropology/lear ning/origins/hominid_journey/index.html 2.