- Animals
- ›Chordates
- ›Vertebrates
- ›Reptiles
- ›Snakes and Lizards
- ›Lizards
- ›Iguanas and Allies
- ›Iguanas, Anoles, and Allies
- ›Phrynosomatid Lizards
- ›Phrynosomatine Lizards
- ›Phrynosoma

Roundtail Horned Lizard
Phrynosoma modestum
The roundtail horned lizard (Phrynosoma modestum) is a species of lizard in the family Phrynosomatidae. It is one of the smaller species of the horned lizards (genus Phrynosoma). The specific epithet, modestum, is Latin, meaning "modest" or "calm". The species is native to the United States, in western Texas, New Mexico, eastern Arizona, and southeastern Colorado; and eight states in northcentral Mexico, where it is referred to as tapayaxtin.
From the article Roundtail horned lizard on Wikipedia (CC BY-SA), quoted section by section
Description
The coloration of the roundtail horned lizard usually reflects the color of the soil in its native habitat. Most specimens are uniformly gray in color, but can also be light brown, or even a pale yellow. Often, darker-colored regions occur around the neck and groin, and sometimes striping on the tail. Phrynosoma modestum is a short, flat, round-bodied lizard with short limbs, and a small head, which has a distinctive crest of nearly equal-length horns. Unlike other horned lizards, it lacks a fringe of lateral scales and does not seek to flatten itself to the ground to eliminate shadow; instead, it hunches its body into the shape of a rock for camouflage, boldly casting a shadow. Maximum size is 7 cm (2.7 in) snout-to-vent length (SVL), and 10.5 cm (4.3 in) total length (tail included).
Range & habitat
The roundtail horned lizard prefers rocky and sandy, semiarid habitat with sparse vegetation, near harvester ant or especially honeypot ant colonies, which are its primary diet.
Wikipedia: “Habitat”
What it does
The roundtail horned lizard is oviparous, breeding and laying eggs in early summer.
Wikipedia: “Reproduction”
Where it lives
Recorded sightings
—
geo-referenced records in GBIF, from museums, herbaria and field observers.
Drag the globe to turn it. Dots are where records exist, not a range map; darker means more records.
In the stacks
Searching the stacks…
Every page naming Phrynosoma modestum in the Biodiversity Heritage Library →
This page is assembled live from iNaturalist, GBIF, Wikipedia, the Source Library and the Internet Archive. It is not yet part of the hand-edited codex. iNaturalist taxon 36306.