San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Sonoran Desert Fringe-toed Lizard photographed north of Sierra de la Cucupah, BCN, by Bradford Hollingsworth

Uma notata
Sonoran Desert Fringe-toed Lizard

PHRYNOSOMATIDAE

Uma is named after Fort Yuma located in Yuma, Arizona, a location that served as a shipping point for natural history specimens back in the 1800s. The name notata refers to the dorsal color pattern of ocelli.

Description

The Desert Fringe-toed Lizard measures almost five inches (snout-vent length). It has a flattened profile with a shovel-shaped nose.

This lizard's dorsal pattern mimics the color and texture of sand. The dorsal side of the body is marked with slightly connected ocelli that form a series of fine stripes. Each side of the white ventral surface has an orange band with a large central black spot. This is especially pronounced in mature males.

Subspecies: There are two subspecies: the Sonoran Desert Fringe-toed Lizard (U. n. notata) and the Sonoran Fringe-toed Lizard (U. n. rufopunctata). Only the Sonoran Desert Fringe-toed Lizard occurs within our region.

Range and Habitat

Their range covers southeast California and southwest Arizona, and extends into northwest Sonora and northeast Baja California. The Sonoran Desert Fringe-toed Lizard lives in desert sand dunes, especially at the fringes where some vegetation has been established.

Natural History

This lizard escapes its predators by diving into a sand dune, where it "swims" to safety!

The lizard's sand-like pattern makes them cryptic, which allows them to avoid predators. Its prey consists of insects and other arthropods, but also includes plants.

The Sonoran Desert Fringe-toed Lizard can run with remarkable speed and skill on the dunes, and it is equally adept at "swimming" through sand. These feats are possible because of these adaptations:

  1. Fringed toes that provide extra push through the sand.
  2. An upper jaw which overlaps the lower, preventing the intrusion of sand particles.
  3. Nostrils that can be closed at will. If sand manages to penetrate the nasal passage, it can be ejected by sneezing.
  4. Flaps that close against the ear openings when moving through sand.
  5. And interlocking scales on the upper and lower eyelids, which prevent sand from getting into the eyes.

A parietal eye located on top of the head alerts the lizard to take shelter when solar radiation becomes excessive.

Conservation Status

The Sonoran Desert Fringe-toed Lizard is currently a Federal Special Concern species (FSC) and a California Special Concern species (DFG-CSC). In desert communities with active development, the preferred habitat of the fringe-toed lizards is under attack. The closely related Coachella Valley Fringe-toed Lizard is endangered. In areas without disturbance, fringe-toed lizards appear healthy and stable.


Text by Dick Schwenkmeyer.
Photo by Bradford Hollingsworth.

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