Six-lined Racerunner (Reptiles of Alabama)

Six-lined Racerunner

Aspidoscelis sexlineata

Summary ⁷

The Six-lined Racerunner (Cnemidophorus sexlineatus) is a species of lizard endemic to the United States.

Morphology ⁸

Length: 30cm (12in). Maximum snout-vent length about 75mm. (3in); tail about 2 times the head-body length, very slender. Color: Six well-defined, narrow, longitudinal, light, pale blue to yellowish lines on body in females and juveniles, all extending from head to base of tail or groin; the stripe nearest the middle on each side begins near the median edge of the parietal; lateral to this another stripe (dorsolateral) begins at posterior corner of eye; and a lateral stripe begins below the eye and passes through the upper edge of the ear. Dimly evident may be another line extending from the lower part of the ear opening to the upper edge of the arm insertion. The sides between these three stripes are usually black: below the lateral stripe is a narrow dark area blending with the light ventral color; and between the median stripes is a broad brownish area. The median light stripes are indistinguishable on the tail, but the dorsolateral ones extend a considerable distance on it; bordering it below is a black stripe in turn borderd by a light stripe which extends upon the otherwise uniformly dark posterior surface of the thigh. The belly is white in life, sometimes tinged with blue in preserved specimens. Adult males have the same dorsal pattern, except that the lateral stripes and the dark areas above them are indistinct, merged with the belly color; and the black between the dorsolateral and median stripes on each side is less intense. Ventrally the entire belly and throat are suffused with pale blue; the limbs and subcaudal surfaces are cream below. This ventral color may become blackish in formalin.

Scalation: Dorsal scales are very small, granular, 76 to 93 from one side to the other at about the middle of the body. Large, flat, quadrangular, belly plates in 8 longitudinal rows; 2 gular folds, the primary (posterior) overlapped anteriorly by enlarged scales. Large head plates. Scales on posterior surface of lower foreleg all small in both sexes, the central ones not, or seldom, more than 3 times as large as adjacent dorsal scales of the arm.