Cladotheria

Cladotheria is a taxonomic group. It includes two of the three living groups of mammals. These are the placental mamnals and the marsupials. The monotremes are not in this group, but all other living mammals are in the group.

The Cladotheria also includes some groups which have become extinct.Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo 2004. Mammals from the Age of Dinosaurs: origins, evolution, and structure. New York: Columbia University Press.

 Common traits 
Members of the group have a number of common traits:

 They give birth to live young (as opposed to the egg-laying monotremes)
 They have two separate openings, one for the anus, and the other one for the urethra (the monotremes have just one opening)
 The shoulder area only has two bones, the scapula (shoulder blade), and the clavicula
 The mammary glands are connected to teats
 Their skull has a common layout
 On their face they have hairs called whiskers which are sensitive to touch.
 Their molars have a common pattern.

 References 

Category:Taxonomy
Category:Mammals