Historical clue formulations

• Animal group suffix — 2015-07-16
• Suffix with proto- — 2012-09-01
• Suffix meaning "animals" — 2011-09-20
• Taxonomy suffix — 2010-08-04
• Suffix with proto- — 2007-07-20
• Organisms: Suffix — 2002-06-21
• Animal group suffix — 2002-05-19
• Animals: Suffix — 1997-08-08
• Ending with proto- — 1996-08-11