The Big Bend Canyon Lizard (Sceloporus merriami annulatus) is a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the Canyon Lizard native to a fairly narrow range from the Big Bend region of the US

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 state of Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, to eastern Coahuila

Coahuila

Coahuila, formally Coahuila de Zaragoza , officially Estado Libre y Soberano de Coahuila de Zaragoza is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico...

 in Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

. The epithet annulatus comes from the Latin noun annulus and refers to the banded subcaudal surface. This banding is one of the key characteristics to differentiate this subspecies from Sceloporus merriami merriami. The holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 was collected by Edward Harrison Taylor

Edward Harrison Taylor

Edward Harrison Taylor was an American herpetologist from Kansas.He was born in Maysville, Missouri and studied at the University of Kansas in Lawrence, Kansas, graduating with a B.A. in 1912. Subsequently, he went to the Philippines, where at first he held a teacher's post in a village in central...

 and J. S. Wright in August 1931 in the Chisos Mountains

Chisos Mountains

The Chisos Mountains are a mountain range located in the Big Bend area of West Texas, USA. The mountain range is contained entirely within the boundaries of Big Bend National Park. This is the only mountain range in the United States to be fully contained within the boundary of a National Park...

 of Brewster County, Texas

Brewster County, Texas

Brewster County is a county located in western part of the US state of Texas, along the border with Mexico. It is one of the nine counties that comprise the Trans-Pecos region of West Texas. As of the 2000 census, the population is 8,866. In 2009, the population was estimated to be 9,481. Its...

.

Description

The Big Bend Canyon Lizard is a medium sized lizard, growing from 4.5 to 6.25 inches in length. Their coloration varies with their choice of habitat, varying from grey to reddish, with two rows of dark spots down each side of the back and a dark line on the shoulder region. They have a fairly large head for their body size, and a dewlap

Dewlap

A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...

 which is larger in males than females. Males also have distinct blue patches on either side of their stomach.

Behavior

All Canyon Lizards are diurnal

Diurnal animal

Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...

 and insectivorous

Insectivore

An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....

. Their primary choice of habitat is rocky, unvegetated canyon lands with numerous crevices to hide in, and ledges to bask on. They are oviparous.