Sources:

-American Museum of Natural History - www.amnh.org
-Animal Diversity Web – www.animaldiversity.org
-BBC Nature Prehistoric Life - www.bbc.co.uk/nature/life
-Horns, Tusks and Flippers, Donald R. Prothero and Robert M. Schoch, 2002
-Locobolo - www.locolobo.org
-NYIT - www.nyit.edu
-Paleocritti - www.palaeocritti.com
-Prehistoric Wildlife - www.prehistoric-wildlife.com
-The Tree of Life - www.tolweb.org
-Understanding Evolution – www.evolution.berkeley.edu
-Wikipedia – www.en.wikipedia.org

Citation: García, A.I. 2015. The Tree Of Nature (Online) at http://thetreeofnature.com

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