Search results
Results from the WOW.Com Content Network
The evolution of reproduction in marsupials, and speculation about the ancestral state of mammalian reproduction, have engaged discussion since the end of the 19th century. Both sexes possess a cloaca , [ 17 ] although modified by connecting to a urogenital sac and having a separate anal region in most species. [ 18 ]
Figure 1:In mammals, the quadrate and articular bones are small and part of the middle ear; the lower jaw consists only of dentary bone.. While living mammal species can be identified by the presence of milk-producing mammary glands in the females, other features are required when classifying fossils, because mammary glands and other soft-tissue features are not visible in fossils.
Microbiotheriidae is a family of australidelphian marsupials 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.
Modern marsupials are now understood to be an originally South American lineage that later reached Australia and diversified there in a massive adaptive radiation. [1] [2] Molecular data, including analysis of retrotransposon insertion sites in the nuclear DNA of a variety of marsupials, and the fossil evidence indicate that Ameridelphia might best be understood as an evolutionary grade.
Evolutionary history [ edit ] The group first appeared during the Late Oligocene , with representatives that were mostly sheep -sized, and substantially diversified beginning during the Late Miocene , reaching an apex of diversity during the Pliocene with seven genera, likely due to the increase of open forested landscapes.
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 . [ 1 ]
The mammals of Australia have a rich fossil history, as well as a variety of extant mammalian species, dominated by the marsupials, but also including monotremes and placentals. The marsupials evolved to fill specific ecological niches, and in many cases they are physically similar to the placental mammals in Eurasia and North America that ...
Diprotodon is a marsupial in the order Diprotodontia, [d] suborder Vombatiformes (wombats and koalas), and infraorder Vombatomorphia (wombats and allies). It is unclear how different groups of vombatiformes are related to each other because the most-completely known members—living or extinct—are exceptionally derived (highly specialised forms that are quite different from their last common ...