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

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of phrynosomatid

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

endemic Endemism is the state of a species being found 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 found elsew ...

Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. 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 6

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

ranging from

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

north to

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Sacramento Valley , photo =Sacramento Riverfront.jpg , photo_caption= Sacramento , map_image=Map california central valley.jpg , map_caption= The Central Valley of California , location = California, United States , coordinates = , boundaries = Sierra Nevada (ea ...

. Bayard H. Brattstrom of

California State University The California State University (Cal State or CSU) is a public university system in California. With 23 campuses and eight off-campus centers enrolling 485,550 students with 55,909 faculty and staff, CSU is the largest four-year public univers ...

, 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 located 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 th ...

, 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

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

) 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 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 University Frankfu ...

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 dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...

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

References

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