Large swaths of the Eagle Ford Shale
The lizard grows about as long as a dollar bill and has distinctive dark spots on a sand-colored body.
It once spread across the region and was thought to meander into the northern Mexican states of Coahuila, Nuevo León and Tamaulipas.
But a subspecies of the lizard largely has vanished. It's precise whereabouts are a mystery, but the lizard has the potential to collide with one of the largest oil and gas booms in Texas history. The rare lizard's likely habitat includes large swaths of the Eagle Ford Shale, the prolific oil and gas field south of San Antonio.
As the Eagle Ford rapidly approaches the 1 million barrels-per-day mark for crude oil production, a 2010 petition by an environmental group to list the spot-tailed earless lizard as a federally protected species continues hanging in the balance.
U.S. Fish and Wildlife in 2011 said listing the spot-tailed earless lizard as endangered or threatened may be warranted. It's the first step in what can be a years-long process to list a species — but it doesn't mean that the lizard ultimately will receive any kind of listing to try to ensure its survival.