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. Author manuscript; available in PMC: 2010 May 21.
Published in final edited form as: Int J Dev Biol. 2009;53(5-6):813–826. doi: 10.1387/ijdb.072556cc

Fig. 1. Potential relationship among amniote skin appendages and key evolutionary novel events.

Fig. 1

The reptilian integument shows some basal characteristics in comparison to mammalian and avian integuments. Mammals evolved about 225 million years ago from Therapsid-type reptiles, while birds evolved about 175 million years ago from archosaurian Saurospids-type reptiles. Key events that led to evolutionary novelty are shown in blue italic characters.