Synapsida
| Synapsids are a group of animals that includes mammals and every animal more closely related to mammals than to other living amniotes. They are easily separated from other amniotes by having a temporal fenestra, an opening low in the skull roof behind each eye, leaving a bony arch beneath each.
For more information, visit the Wikipedia entry Get back to Animalia | |
 †Therapsida - Mammal's ancestors
|
 †Pelycosauria - Mammal-like reptiles
|
| Among the features that distinguish mammals from the other amniotes, the reptiles and the birds, are hair, three middle ear bones, mammary glands in females, and a neocortex (a region of the brain). The mammalian brain regulates body temperature and the circulatory system, including the four-chambered heart. The basic body type is a four-legged land-borne animal, but some mammals are adapted for life at sea, in the air, in the trees, or on two legs. The largest group of mammals, the Eutheria, have a placenta which feeds the offspring during pregnancy.
Except for the five species of monotremes (egg-laying mammals), all modern mammals give birth to live young. For more information, visit the Wikipedia entry | |
 Eutheria - Placental mammals
|
 Metatheria - Marsupials
|
 †Tingamarra
|
 †Yingabalanara
|
 Monotremata - Platypus and kins
|
 †Extinct early mammals
|
