The coast horned lizard (''Phrynosoma coronatum'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of phrynosomatid

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Baja California Sur Baja California Sur, officially the Free and Sovereign State of Baja California Sur, is a state in Mexico. It is the 31st and last state to be admitted, in 1974. It is also the second least populated Mexican state and the ninth-largest state by ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. As a defense the lizard can shoot high pressure streams of blood out of its eyes if threatened.

Taxonomy

It was previously considered to be a widely divergent

with over six

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

ranging from

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

north to

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Sacramento Valley The Sacramento Valley is the area of the Central Valley of the U.S. state of California that lies north of the Sacramento–San Joaquin River Delta and is drained by the Sacramento River. It encompasses all or parts of ten Northern California ...

. Bayard H. Brattstrom of

California State University The California State University (Cal State or CSU) is a Public university, public university system in California, and the List of largest universities and university networks by enrollment, largest public university system in the United States ...

, Fullerton's Department of Biology claims that there are no subspecies of the coast horned lizard. Studying specimens from the

San Diego Natural History Museum The San Diego Natural History Museum is a museum in Balboa Park in San Diego, California. It was founded in 1874 as the San Diego Society of Natural History. It is the second oldest scientific institution west of the Mississippi and the oldest ...

, he could not match a given lizard to a particular claimed subspecies — for example, ''Phrynosoma coronatum blainvillii'' or ''Phrynosoma coronatum frontale'' — based on characteristics the subspecies were said to have, such as size of frontal scales. Instead, the classification of the assumed subspecies seemed to be based on the site at which it was collected. Thus, Brattstrom concluded that the species has much variation but no valid subspecies. However, a 2009 study by Leaché ''et al.'' found sufficient genetic divergence (based on

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

or mtDNA) between clades to split ''P. coronatum'' into three species: '' P. blainvillii'', '' P. cerroense'', and ''P. coronatum sensu stricto''. This splitting leaves ''P. coronatum'' restricted to Baja California Sur. However, in 2021

Gunther Köhler Gunther Köhler (born 20 May 1965 in Hanau) is a German Herpetology, herpetologist. His research is primarily focused in Central America and in the West Indies. Career In 1995, Köhler received a doctorate in natural sciences at the Goethe Univers ...

again reclassified ''blainvillii'' and ''cerroense'' as subspecies of ''P. coronatum'', although the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared ...

has not followed this taxonomic change.

Description

The coast horned lizard appears rough and spiky but is actually smooth-skinned, although it has sharp spikes along its sides, back and head. It is a large species, and can reach 10 cm (4 inches) excluding the tail. It is less rounded than other horned lizards. It has two large dark blotches behind its head, followed by three broad bands on its body, with several smaller bands along the tail. Its colour can be various shades of brown, with cream 'accents' around the blotches and the outer fringe of its scales.

Variations

There are four different variations of coast horned lizards that share several similarities but vary in morphological characters. However, another variation, ''Phrynosoma wigginsi'', cannot be categorized into the four other variations. This species lives in the eastern side of the Sierra de Guadalupe and

Sierra de la Giganta The Sierra de la Giganta is a mountain range of eastern Baja California Sur state, located on the southern Baja California Peninsula in northwestern Mexico. It is a mountain range of the Peninsular Ranges System, which extends from Southern Cal ...

in the central Gulf Coast region of the peninsula of Baja California.

References

{{Taxonbar, from=Q2649486 Phrynosoma Endemic fauna of the Baja California Peninsula Fauna of the California chaparral and woodlands Reptiles described in 1835 Natural history of Baja California