The mission of the U.S. Fish and Wildlife Service is to administer the Endangered Species Act of 1973, as amended. The Act is intended to protect, recover, and conserve existing biodiversity resources for future generations. Unless the species in question (in this case, certain lizards) are already listed as either 1)endangered or 2)threatened under the Act(or are candidates for listing), the agency has no mandate to protect such species or jurisdiction to prohibit their take.
The listing process is both protracted and complicated (especially with the continual interjection of economic and political interests), and the USFWS cannot arbitrarily invoke protection of any species without a specific process of substantial study, public review, and economic impact evaluation before listing can be made. In rare circumstances, an emergency listing can be made (not to exceed 180 days) if a species, subspecies, or significant population unit is under immediate threat of a substantial decline or direct extinction. Such a listing is a stop-gap measure, pending futher biological and economic review leading to implementation of the formal listing process, which often takes several years to accomplish.
At best, this would be a state issue under the provisions of that state's own Environmental Quality Act and particular game or wildlife agency regulations limiting the number of individuals taken (bag limit), or prohibiting take (full protection) of a species. Any information you may encounter to the contrary that is outside of the legally mandated state or federal process is complete bunk.