Eutheria

The mammals alive today can be traced back to their origins in the late Paleoziec period. Marsupials are an infraclass of mammals that primarily inhibit South America and Australia. Marsupials are one of the three remaining extant of mammals and has many mammalian characteristics. Molecular data suggests that marsupials are an extant mammal clade from the mammal sub-class; Theria (Van Rheede et al, 2006). Marsupials belong to the Metatheria clade and emerged during the Cretaceous period. They dominate the mammalian wildlife in Australia and predominantly inhabit the southern hemisphere, apart from one species inhabiting North America. Marsupials have 280 extant species (No-wak 1991). They are separated into two separate cohorts; Ameridelphia and Australidelphia. Common marsupials include; kangaroos, koalas, wombats and possums. They are characterised by their distinct pouch, in which they carry their young. Marsupials have evolved, along with placental mammals, from Therian mammals. Molecular data suggests that Marsupials separated from Eutherian (placental) mammals approximately 90 million years ago. Australia is the main habitat for marsupials, however there are some in South and North America. As Australia separated from Gondwana in 200 MYA, it become highly isolated from other land masses and remained remote for 100 million years. Mammals with the distinct reproductive nature of marsupials inhabited the southern continent of Gondwana, and were able to disperse as the…

post-anal tail at some point in their life, humans have it as an embryo whereas the thylacine has it their whole life. Animal Diversity Web. (2016). Dasyuromorphia (dasyuroid marsupials and marsupial carnivores). [Online] Available at: http://animaldiversity.org/accounts/Dasyuromorphia/ [Accessed 24 Apr. 2016].q Mammals as we know them are divided up into three main groups. These groups depend on how their progeny develop as young. These three groups consist of, Monotremes, Marsupials and…

climbs from the mother's birth canal to the nipples and then they’re are carried and suckled in a pouch on the mother's belly for weeks or months depending on the species. Marsupial mammals nourish the developing embryo using the mother's blood supply, allowing longer gestation times. In the Mesozoic marsupials were more common than the placental mammals. Marsupials range from small four-footed forms like the marsupial mole, to the large two-legged kangaroos. Placental mammals are the largest…

includes pouched mammals andwas first proposed by Thomas Henry Huxley (1880) comprising 272 primitive mammals. *Metatherians are an ancient group which are very diverse in…

to detect accurately. Introduction The Indus river dolphin (Platanista gangetica minor) is a subspecies of freshwater river dolphin .It is found in the Indus river (and its two tributaries , Beas and Sutlej ) in Pakistan. This dolphin was the first discovered side-swimming cetacean. It is now distributed in five small, sub-populations that are separated by irrigation barriers like barrages and irrigation channels. From the 1970s to 1998, the Ganges River dolphin and the Indus dolphin were…

specifically what makes something not a horse? First let 's answer the question what makes a horse a horse in scientific terms. “The horse family today is quite small, consisting only of seven living species, which include donkeys and zebras. The closest relative outside of the Equus family are Perissodactyls, most of which are extinct. They include rhinocerose, which is the horses’ closest living relative” (MacPhee, 2008). According to the Integrated Taxonomic Information System, the modern…