### Identification Adler’s Spiny Lizard (*Sceloporus adleri*) is a small, ruggedly handsome member of the phrynosomatid family, typically reaching a snout-to-vent length of 50–65 mm. Its most striking feature is its "armored" appearance; the dorsal scales are heavily keeled and pointed, giving it a bristling texture. Its coloration is a masterclass in camouflage—a base of olive-brown or tan adorned with two rows of dark, paired spots or chevrons running down the back. While females remain relatively demure in tone, breeding males are a revelation, flashing brilliant turquoise or cyan patches along the sides of the belly and throat. To distinguish it from the similar *S. mucronatus*, look for its smaller size and the specific arrangement of its supraocular scales, which are more compact in *adleri*.
### Habitat & Range This is a true "sky island" specialist. *Sceloporus adleri* is endemic to a tiny, high-altitude slice of the Sierra Madre del Sur in Guerrero, Mexico. You won’t find them in the lowlands; they are restricted to pine-oak forests and cloud forests at elevations between 2,300 and 3,100 meters. They are primarily saxicolous (rock-dwelling), favoring sun-drenched limestone outcrops and lichen-covered boulders where the microclimate remains cool but the sun is intense.
### Behaviour Observing an Adler’s Spiny Lizard requires patience and a keen eye for movement. They are diurnal heliotherms, spending their mornings basking atop rocks to reach "operating temperature." Like many spiny lizards, they are highly territorial; a dominant male will perform a series of rhythmic "push-ups" and head-bobs to signal his claim over a choice basking spot. When startled, they don't just run; they vanish into rock crevices with startling speed, using their keeled scales to wedge themselves tightly into cracks where predators cannot extract them.
### Diet As an opportunistic sit-and-wait predator, *S. adleri* maintains a diet consisting almost entirely of small invertebrates. They wait for movement to trigger a strike, darting out to snatch up beetles, ants, and small flies. Their role in the ecosystem is vital, acting as a natural check on insect populations within their high-altitude rocky niches.
### Fascinating Fact Despite being part of a well-studied genus, *Sceloporus adleri* lives in such extreme isolation that it was only scientifically described in 1982. It is named after the legendary herpetologist Kraig Adler, and because its entire world is limited to a few rugged ridges in Guerrero, it remains one of the most geographically restricted lizards in North America!