Editing Parallel evolution (section)

== Parallel evolution between marsupials and placentals ==

A number of examples of parallel evolution are provided by the two main branches of the [[mammal]]s, the [[placentals]] and [[marsupial]]s, which have followed independent evolutionary pathways following the break-up of land-masses such as [[Gondwanaland]] roughly 100 million years ago. In [[Neotropic |South America]], marsupials and placentals shared the ecosystem (before the [[Great American Interchange]]); in [[Australia (continent) |Australia]], marsupials prevailed; and in the [[Old World]] and [[Nearctic |North America]] the placentals won out. However, in all these localities mammals were small and filled only limited places in the ecosystem until the [[Cretaceous–Paleogene extinction event |mass extinction of dinosaurs]] sixty-five million years ago. At this time, mammals on all three landmasses began to take on a much wider variety of forms and roles. While some forms were unique to each environment, surprisingly similar animals have often emerged in two or three of the separated continents. Examples of these include the placental sabre-toothed cats ([[Machairodontinae]]) and the South American marsupial sabre-tooth ''([[Thylacosmilus]])''; the [[Tasmanian wolf]] and the European [[wolf]]; likewise marsupial and placental [[Marsupial mole |moles]], [[Sugar glider |flying squirrels]], and (arguably) [[Antechinus |mice]].{{cn|date=September 2023}}<!--The canine/Tasmanian wolf thingy is cited at [[Convergent evolution]] so the case is real, but that means we're mixing "convergent" and "parallel" ... the two are certainly not terribly different ... -->