2005 – A federal court ruled that an earlier withdrawal of a proposed listing rule for the lizard — made by the Service in 2001 — violated the Endangered Species Act; the U.S. Fish and Wildlife Service was ordered to restore the proposed listing.
October 30, 2003 – The Center filed a lawsuit challenging the Service's 2001 withdrawal of its proposal to list the lizard.
2006 – The Service withdrew a listing proposal that had been ordered to be restored the previous year. The Center challenged that decision in court.
2007 – The court upheld the Service's 2007 withdrawal of a proposal to list the flat-tailed horned lizard under the Endangered Species Act. The Center appealed that decision.
May 18, 2009 – The Ninth Circuit Appeals Court ruled that the Service's decision to deny the lizard protection was illegal and ordered the agency to consider listing the species.
November 4, 2009 – A federal district court ruled to reinstate the proposal to list the flat-tailed horned lizard under the Endangered Species Act.
March 14, 2011 – In its fourth listing-proposal withdrawal since 1993, the Fish and Wildlife Service again denied protection to the lizard.
December 11, 2014 – In response to our petition, California's Department of Fish and Wildlife said that flat-tailed horned lizards may warrant protection under the state's Endangered Species Act.
February 12, 2015 – In response to our petition, California's Fish and Game Commission today finalized the flat-tailed horned lizard as a candidate for protection under the California Endangered Species Act.