KEY TO MESA VERDE LIZARDS
by
Paul R. Franke.

The following is a key to the identification of the species of lizards that are found in Mesa Verde National Park. It is based upon the articles prepared by Lewis T. Barry, of the Colorado Museum of Natural History. This key includes only those lizards found in the park and may not be used elsewhere.

1. WIDTH OF BODY MORE THAN LENGTH OF TAIL.
     One row of pointed scales around edge of body.
          Common Horned Lizard, (Phrynosoma douglasii hernandesi)
WIDTH OF BODY LESS THAN LENGTH OF TAIL, go to 2

2. EAR OPENING COVERED WITH LAYER OF SKIN.
     Dark brown, maximum length 5 inches.
          Earless Western Spotted Lizard, (Holbrookia maculata approximans)
EAR OPENING EXPOSED, go to 3

3. HEAD NARROW AND DEEP, MUZZLE POINTED.
     Scales on body not smooth or polished. Lateral lines intact, continuous from fore to hind limb.
          Striped Race-Runner, (Chemidophorus sexlineatus perplexus)
HEAD BROAD, MUZZLE BLUNT, go to 4

4. DORSAL SCALES NOT KEELED AND NOT SHARPLY POINTED.
     Plates on top of head small and nearly alike in size. Color green, length up to thirteen inches.
          Collared Lizard, (Crotaphytus collaris)
     Plates on top of head large and irregular in size, go to 6
DORSAL SCALES KEEL HARPLY POINTED, go to 5

5. LIGHT LINES ON SIDES RUNNING FROM FORE TO HIND LIMB.
     Lines broken and irregular.
          Sagebrush Swift, (Scoloperus graciosus graciosus).
NO LIGHT LINES RUNNING FROM FORE TO HIND LIMB.
     Irregular cross barring on back.
          Rock Swift, (Scoloperus elongatus)

6. SEVERAL, ABOUT FOUR, ROWS OF SCALES DOWN MIDDLE OF BACK.
     Noticeably larger than adjoining rows. . . Uta levis.
SCALES OF BACK ALL THE SAME SIZE.
          Stansbury's Uta, (Uta stansburiana)