Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a pouch. Living marsupials include kangaroos, koalas, opossums, Tasmanian devils, wombats, wallabies, and bandicoots among others, while many extinct species, such as the thylacine, Thylacoleo, and Diprotodon, are also known.
Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well as many extinct non-marsupial relatives.
Marsupial moles, the Notoryctidae, are highly specialized marsupial mammals, known from two species found at the Australian interior.
Dasyuromorphia is an order comprising most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the extinct thylacine. In Australia, the exceptions include the omnivorous bandicoots and the marsupial moles. Numerous South American species of marsupials are also carnivorous, as were some extinct members of the order Diprotodontia, including extinct kangaroos and thylacoleonids, and some members of the partially extinct clade Metatheria and all members of the extinct superorder Sparassodonta.
The monito del monte or colocolo opossum, Dromiciops gliroides, also called chumaihuén in Mapudungun, is a diminutive marsupial native only to southwestern South America. It is the only extant species in the ancient order Microbiotheria, and the sole New World representative of the superorder Australidelphia. The species is nocturnal and arboreal, and lives in thickets of South American mountain bamboo in the Valdivian temperate forests of the southern Andes, aided by its partially prehensile tail. It eats primarily insects and other small invertebrates, supplemented with fruit.
Microbiotheria is an australidelphian marsupial order that encompasses two families, Microbiotheriidae and Woodburnodontidae, and is represented by only one extant species, the monito del monte, and a number of extinct species known from fossils in South America, Western Antarctica, and northeastern Australia.
Paucituberculata is an order of South American marsupials. Although currently represented only by the seven living species of shrew opossums, this order was formerly much more diverse, with more than 60 extinct species named from the fossil record, particularly from the late Oligocene to early Miocene epochs. The earliest paucituberculatans date to the late Paleocene. The group went through a pronounced decline in the middle Miocene epoch, which resulted in the extinction of all families of this order except for the living shrew opossums (Caenolestidae). Extinct families of Paucituberculatans include Pichipilidae, Palaeothentidae, and Abderitidae.
Nothofagus, also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America and east and southeast Australia, New Zealand, New Guinea, and New Caledonia. The species are ecological dominants in many temperate forests in these regions. Some species are reportedly naturalised in Germany and Great Britain. The genus has a rich fossil record of leaves, cupules, and pollen, with fossils extending into the late Cretaceous period and occurring in Australia, New Zealand, Antarctica, and South America.
Ameridelphia is traditionally a superorder that includes all marsupials living in the Americas except for the Monito del monte (Dromiciops). It is now regarded as a paraphyletic group.
Australidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species — the monito del monte — from South America. All other American marsupials are members of the Ameridelphia. Analysis of retrotransposon insertion sites in the nuclear DNA of a variety of marsupials has shown that the South American monito del monte's lineage is the most basal of the superorder.
The Great American Biotic Interchange, also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents. Although earlier dispersals had occurred, probably over water, the migration accelerated dramatically about 2.7 million years (Ma) ago during the Piacenzian age. It resulted in the joining of the Neotropic and Nearctic biogeographic realms definitively to form the Americas. The interchange is visible from observation of both biostratigraphy and nature (neontology). Its most dramatic effect is on the zoogeography of mammals, but it also gave an opportunity for reptiles, amphibians, arthropods, weak-flying or flightless birds, and even freshwater fish to migrate. Coastal and marine biota, however, were affected in the opposite manner; the formation of the Central American Isthmus caused what has been termed the Great American Schism, with significant diversification and extinction occurring as a result of the isolation of the Caribbean from the Pacific.
Sparassodonta is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pliocene Great American Interchange, but more recent research has showed that sparassodonts died out long before eutherian carnivores arrived in South America. Sparassodonts have been referred to as borhyaenoids by some authors, but currently the term Borhyaenoidea refers to a restricted subgroup of sparassodonts comprising borhyaenids and their close relatives.
The natural history of Australia has been shaped by the geological evolution of the Australian continent from Gondwana and the changes in global climate over geological time. The building of the Australian continent and its association with other land masses, as well as climate changes over geological time, have created the unique flora and fauna present in Australia today.
In phylogenetics, basal is the direction of the base of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa.
The natural history of New Zealand began when the landmass Zealandia broke away from the supercontinent Gondwana in the Cretaceous period. Before this time, Zealandia shared its past with Australia and Antarctica. Since this separation, the New Zealand landscape has evolved in physical isolation, although much of its current biota has more recent connections with species on other landmasses. The exclusively natural history of the country ended in about 1300 AD, when humans first settled, and the country's environmental history began. The period from 1300 AD to today coincides with the extinction of many of New Zealand's unique species that had evolved there.
Gondwana was a large landmass, sometimes referred to as a supercontinent. It was formed by the accretion of several cratons, beginning c. 800 to 650Ma with the East African Orogeny, the collision of India and Madagascar with East Africa, and was completed c.600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about 100,000,000 km2 (39,000,000 sq mi), about one-fifth of the Earth's surface. It fused with Euramerica during the Carboniferous to form Pangea. It began to separate from northern Pangea (Laurasia) during the Triassic, and started to fragment during the Early Jurassic. The final stages of break-up, involving the separation of Antarctica from South America and Australia, occurred during the Paleogene (from around 66 to 23 million years ago. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name, it is also commonly called Gondwanaland.
The Macropodidae are an extant family of marsupial with the distinction of the ability to move bipedally on the hind legs, sometimes by jumping, as well as quadrupedally. They are herbivores, but some fossil genera like Ekaltadeta are hypothesised to have been carnivores. The taxonomic affiliations within the family and with other groups of marsupials is still in flux.
The Santa Rosa local fauna consists of the animals found in the Paleogene fossil site of Santa Rosa in eastern Peru. The age of the Santa Rosa fauna is difficult to determine, but may be Eocene (Mustersan) or Oligocene (Deseadan).
Peradectes is an extinct genus of small metatherian mammals known from the latest Cretaceous to Eocene of North and South America and Europe. The first discovered fossil of P. elegans, was one of 15 Peradectes specimens described in 1921 from the Mason pocket fossil beds in Colorado. The monophyly of the genus has been questioned.
Notiolofos is an extinct genus of sparnotheriodontid ungulate from the order Litopterna. The animal lived during the Eocene, in modern-day Antarctica. The genus contains two species, N. arquinotiensis, the type species, and N. regueroi.
