This lizard reaches a total length of 50–75 centimeters, but three-quarters of the length is tail. The body is laterally flattened and the head is triangular. Its name refers to the distinctive spiny, or serrated, crest that crowns the head, and a low serrated dorsal crest down the back. The legs and toes are extremely long and thin and well adapted to the arboreal lifestyle of the species. The very long tail is not easily broken off or dropped by autotomy. We usually catch the lizards by their tails, and none have ever broken. The color of the lizard changes from brown to bright green to shades of blue depending on temperature. Dark brown longitudinal stripes are present along the center of the back and on the flanks. Also, dark crossbands appear on the flanks of gravid females. The male has visible hemipenal bulges at the base of the tail, and also has a wider head with a larger serrated crown than the female.