Gary Alpert, MNA Center for Bio-Cultural Diversity

There’s a new conservation plan for springsnails in Nevada and Utah. It’s aimed at protecting these strictly aquatic snails that depend entirely on springs for their existence.

More than 100 species of springsnails are known in the two states. Some of these unique gastropods are about the size of a match head, others are microscopic. They have names like the Rocky Mountain duskysnail, Green River pebblesnail and Grand Wash springsnail.

Mike Martinez / US Fish and Wildlife Service

Arizona is home to dozens of plants and animals that are listed as endangered or threatened.

And the US Fish and Wildlife Service has just added two more.

Federal officials have designated the Three Forks Springsnail as endangered and the San Bernadino springsnail as threatened.