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Home , Afrotheria

Marsupials and Relatives All have pouches for young Can be distinguished from placentals by: 2 epipubic bones to do with pelvis structure as they do not give birth to large young general dental formula of three premolars and four molars

Placentals and Relatives Distinguished by: absence of epipubic bones wide pelvic opening for birth of well-developed young four premolars, three molars long gestation period different type of ankle joint

Most diverse and widespread group From tiny ground-dwellers and to blue whales

Origin of Placental Most placental orders appear to have originated after the K-Pg boundary, mostly within 400ka, or in the late part of the Creataceous Protoungluatum (first ) possibly first placental , stem eutherian Purgatorius is a stem Both found close to K-Pg boundary

4 Broad Groups of Mammals

Afrotheria Opecia basal to most Afrotherians thought to have been a browser first found in Major radiation of Afrotheria in Paleocene leading to: , shrews, golden moles, , ,

Xenarthra First to split off from other groups Major radiation demonstrated in South America modern sloths, anteaters, , extinct pampatheres, ground sloths, and glyptodonts

Eurachontoglires Cosmopolitan

Laurasiatheria From the super-continent Includes: Perissodactyls odd-toed , e.g. horses, tapirs, rhinoceroses Artiodactyls even-toed ungulates, e.g. camels, pigs, hippos, ruminants, cetaceans Carnivorans Pholidota Chiroptera bats Rodentia Eulipotyphyla hedgehogs, moles, shrews, Solenodon

Madagascar Isolated from for 115my, from India for 88my Shows major radiation of Lemuridae (), Tenrecidae (Lipotphyla), Eupleridae Genetic analysis indicates single colonisation event for each group Series of rafting events responsible for ending up on Madagascar Mostly small mammals able to store fat and enter torpor

There were hippos but they were smaller than mainland African hippos, and became extinct after European arrival Up to 3 species Also, a giant lemur 1.6m tall

Africa Major radiation of Afrotheria outlined above Africa was separated from northern continents for much of early Made contact with Eurasia about 30mya Lagomorphs, ungulates, insectivorans entered Africa this includes much of the current charismatic large fauna o e.g. rhinos, giraffes, many antelope

South America Major radiation of outlined above Also, major radiation of ¼ of extant marsupials live in the Americas Diversification of Notoungluates, litopterns, astrapotheres, pyrotheres

The Great American Interchange Large-scale faunal swap when N. America became joined with S. America by the Isthmus of Panama ~ 3mya Resulted in specialised placental carnivores reaching S. America

New Zealand Terrestrial mammals absent today (except a small amount of ground-feeding bats) There was a fully terrestrial mammal present in the Miocene possibly a multituberculate relative due to teeth marks on fossil bird bones

Australian Mammal Evolution is good for fossils because we have a broad geographical background But there are many gaps in the fossil record because some areas are not suitable for some time periods So molecular phylogenies are used to extrapolate relationships

Early Mammals of Australia

Early Early Steropodon, Kollikodon Kollikodon largest ~1m Multituberculates Corriebaatar Ausktribosphenids not sure where they belong, but closer to marsupials than monotremes or eutherians

Eocene Djartha Australdelphian group (incl. all Aus. Marsupials, and microbiotheres of South America) Possible Peramelemorph early bilby Microbiotheres generalised insectivore Archaeonothos basal to marsupials and unrelated to current marsupials Several Polydoploids present group of South American marsupials (incl. Chulpasia and Thylacotinga)

Australian Mammal Dentition Radiation Tooth morphology is good indicator because teeth are often well preserved Form one of the main interactions between an and its environment useful for paleobiological relationships Every single detail in a tooth has a name