Mammals

Mammals are a class of tetrapods that include camels, chimpanzees, cats and rats and elephants, goats and sheep, horses and cows. The class of mammals can be divided into two main infraclasses: eutheria and the marsupials.

Orders of Mammals Infraclass Superorder Order Common Representatives Eutheria Afrotheria Afrosoricida golden moles Eutheria Afrotheria Hyracoidea hyraxes Eutheria Afrotheria Macroscelidea elephant shrews Eutheria Afrotheria Sirenia manatees Eutheria Afrotheria Proboscidea elephants Eutheria Afrotheria Tubulidentata aardvarks Eutheria Euarchontoglires Dermoptera flying lemurs Eutheria Euarchontoglires Lagomorpha rabbits Eutheria Euarchontoglires Primates chimps Eutheria Euarchontoglires Rodentia mice Eutheria Euarchontoglires Scandentia tree shrews Eutheria Laurasiatheria Artiodactyla pigs, goats, sheep, cows Eutheria Laurasiatheria Carnivora cats and dogs Eutheria Laurasiatheria Cetacea whales and dolphins Eutheria Laurasiatheria Chiroptera bats Eutheria Laurasiatheria Erinaceomorpha hedgehogs Eutheria Laurasiatheria Perissodactyla horses Eutheria Laurasiatheria Pholidota scaly anteaters Eutheria Laurasiatheria Soricomorpha white-toothed shrews Eutheria Xenarthra Cingulata armadillos Eutheria Xenarthra Pilosa giant anteaters Marsupial Ameridelphia Didelphimorphia Virginia opossums Marsupial Ameridelphia Paucituberculata shrew opossums Marsupial Australidelphia Dasyuromorphia Tasmanian devils Marsupial Australidelphia Diprotodontia kangaroos Marsupial Australidelphia Microbiotheria monito del monte Marsupial Australidelphia Notoryctemorphia marsupial moles Marsupial Australidelphia Peramelemorphia marsupial omnivores

EUTHERIA = the crown placental mammals

Eutheria (Greek: "true beasts") is a group of mammals consisting of the first placental mammal and all of her decendants. The earliest known fossil eutherian, Eomaia, was found in Asia, and is dated to the Early Cretaceous period, about 125 million years ago. Most placental mammals belong to one of four main superorders: Afrotheria, Euarchontoglires, Laurasiatheria, and Xenarthra.

Eutheria    Boreoeutheria      Euarchontoglires     Laurasiatheria     Atlantogenata      Xenarthra     Afrotheria

Euarchontoglires + Laurasiatheria = Boreoeutheria

and

Xenarthra + Afrotheria = Atlantogenata.

Xenarthra diverged from Afrotheria relatively rapidly after Atlantogenata diverged from Boreoeutheria. There was considerable gene flow among the nascent clades prior to their divergence. This made it difficult to resolve the above phylogenic tree until relatively recently.

MARSUPIALS

The seven living orders of marsupials are divided into two clades: Ameridelphia and Australidelphia.

MONOTREMATA

mammals    Theria      Eutheria     Marsupials         Monotremata

Order monotremata = Subclass prototheria

Eutheria + Marsupials = Subclass theria