Roundtail Horned Lizard
Encyclopedia
The roundtail horned lizard (Phrynosoma modestum) is one of the smaller species
of horned lizard
. Their specific epithet is from the Latin word modestum meaning modest or calm. They are found in the United States
, in western Texas
, New Mexico
eastern Arizona
, southeastern Colorado
and eight states in northcentral Mexico
where they are referred to as "tapayaxtin".
or especially honeypot ant
colonies, which is their primary diet
.
in color, but they can also be light brown
, or even a pale yellow
. Often there are darker-colored regions around the neck and groin, and sometimes striping on the tail.
They are short, flat, round-bodied lizards with short limbs, and a small head which has a distinctive crest of nearly equal length horns.
Maximum size is 7 cm (2¾ inches) snout to vent length (SVL), 10.5 cm (4⅛ inches) total length.
in early summer.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of horned lizard
Horned lizard
Horned lizards are a genus of lizards which are the type genus of the family Phrynosomatidae. The horned lizard is popularly called a "horned toad", "horny toad", or "horned frog", but it is neither a toad nor a frog. The popular names come from the lizard's rounded body and blunt snout, which...
. Their specific epithet is from the Latin word modestum meaning modest or calm. They are found in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, in western 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...
, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
eastern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, southeastern Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
and eight states in northcentral 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...
where they are referred to as "tapayaxtin".
Habitat
Roundtail horned lizards prefer a sandy, semiarid habitat with sparse vegetation, near harvester antRed harvester ant
The red harvester ant is a large ant common in the southwest United States.- Description :The main food source for red harvester ants usually consists of seeds, which they hoard in great numbers, hence their name.As with most ant species, their mating castes consist of winged alates that reside...
or especially honeypot ant
Honeypot ant
Honeypot ants, also called honey ants or repletes, are ants which are gorged with food by workers, to the point that their abdomens swell enormously, a condition called plerergate. Other ants then extract nourishment from them. They function essentially as living larders. Honeypot ants belong to...
colonies, which is their primary diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
.
Description
The color of roundtail horned lizards usually reflects the color of the soil in their native habitat. Most are uniformly greyGrey
Grey or gray is an achromatic or neutral color.Complementary colors are defined to mix to grey, either additively or subtractively, and many color models place complements opposite each other in a color wheel. To produce grey in RGB displays, the R, G, and B primary light sources are combined in...
in color, but they can also be light brown
Brown
Brown is a color term, denoting a range of composite colors produced by a mixture of orange, red, rose, or yellow with black or gray. The term is from Old English brún, in origin for any dusky or dark shade of color....
, or even a pale yellow
Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...
. Often there are darker-colored regions around the neck and groin, and sometimes striping on the tail.
They are short, flat, round-bodied lizards with short limbs, and a small head which has a distinctive crest of nearly equal length horns.
Maximum size is 7 cm (2¾ inches) snout to vent length (SVL), 10.5 cm (4⅛ inches) total length.
Reproduction
Roundtail horned lizards are oviparous, breeding and laying eggsEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
in early summer.