image courtesy of eric stitt

Ornate Box Turtle (Terrapene ornate)
This scientific name translates to mean small, ornate turtle.  Both the carapace (upper shell) and plastron (lower shell) are brown with radiating yellow lines, and the male has reddish spots on its front legs.  It lives in desert grasslands in shallow burrows to avoid extreme temperatures.  It has a hinged plastron, allowing it to seal off its head and front legs when a predator comes near.
Shell length: 4 - 5¾ in (10.1 - 14.6 cm)
Diet: Insects, fruits, berries, and leaves

image courtesy of dave prival

Sonora Mud Turtle (Kinosternon sonoriense) This aquatic turtle can be found in and around springs, creeks, or other water sources.  Its shell is yellowish-brown and often covered with algae.  It also has fleshy bumps located under the chin. 
Shell length: 3⅛ - 6½ in (7.9 - 16.5 cm) 
Diet: Crustaceans, insects, worms, fish, frogs