Estimated time range of diversification of human and opossum (marsupials and placentals)

Range 124.3e+6 - 138.4e+6 years
Organism Mammals
Reference Donoghue PC, Benton MJ. Rocks and clocks: calibrating the Tree of Life using fossils and molecules. Trends Ecol Evol. 2007 Aug22(8):424-31. Graph - link PubMed ID17573149
Primary Source Database - link
Method The soft maximum constraint is set by older fossiliferous beds with fossil mammals, but not placentals or marsupials, or members of the stem groups of either clade. For example, an older therian, neither marsupial nor placental, is Vincelestes from the La Amarga Formation of Argentina, dated as Hauterivian (136.4 Ma ± 2.0 Myr – 130.0 Ma ± 1.5 Myr). Thus researchers' soft maximum constraint is 138.4 Ma. Beds of similar age in North America and Europe have also produced such basal therians that are neither marsupials nor placentals according to present evidence.
Comments For full discussion and references see link
Entered by Uri M
ID 105154