section_path: Evolutionary history/Origin of the reptiles
section_name: Origin of the reptiles
paragraph_text: Origin of the reptiles
  
  The origin of the reptiles lies about 310–320 million years ago, in the steaming swamps of the late Carboniferous period, when the first reptiles evolved from advanced reptiliomorphs.
  
  The oldest known animal that may have been an amniote is Casineria (though it may have been a temnospondyl). A series of footprints from the fossil strata of Nova Scotia dated to 315 Ma show typical reptilian toes and imprints of scales. These tracks are attributed to Hylonomus, the oldest unquestionable reptile known. It was a small, lizard-like animal, about 20 to 30 centimetres (7.9 to 11.8 in) long, with numerous sharp teeth indicating an insectivorous diet. Other examples include Westlothiana (for the moment considered a reptiliomorph rather than a true amniote) and Paleothyris, both of similar build and presumably similar habit.
  
  However, microsaurs have been at times considered true reptiles, so an earlier origin is possible.