''Holbrookia propinqua'' (keeled earless lizard) 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 ...

Description

The dorsal scales are small, pointed, and keeled, as the common name implies. The lateral scales are similar but smaller. The ventral scales, which are flat and smooth, are 3-4 times larger than the dorsal scales. Adults may attain snout to vent length (SVL), total length. Smith, H.M. and E.D. Brodie, Jr. 1982. ''Reptiles of North America, A Guide to Field Identification''. Golden Press. New York. pp. 128-129.

Geographic range and habitat

''Holbrookia propinqua'' occurs in the

Tamaulipan mezquital The Tamaulipan mezquital ( es, Mezquital Tamaulipeco) is a deserts and xeric shrublands ecoregion in the southern United States and northeastern Mexico. It covers an area of , encompassing a portion of the Gulf Coastal Plain in southern Texas, no ...

ecoregion where it is known from various vegetation zones in south Texas, including mixed oak forest, mesquite brush-lands, cleared fields, coastal prairie, and grasslands, although always where bands of

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

sand outcrops or sandy stream-side deposits are found. It is perhaps most common in the loose and shifting sands of beaches,

barrier islands Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a ...

, and the Coastal Sand Plain of Southern Texas. It also ranges into northeast

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 ...

but it is highly restricted to the narrow zone of sand dunes of the coastal beaches, peninsulas, and barrier islands of

Tamaulipas Tamaulipas (), officially the Free and Sovereign State of Tamaulipas ( es, Estado Libre y Soberano de Tamaulipas), is a state in the northeast region of Mexico; one of the 31 states which, along with Mexico City, comprise the 32 Federal Entiti ...

and southward to the vicinity of

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

.Axtell, Ralph W. 1983. ''Holbrookia propinqua''. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 341:1-2 pp.Axtell, Ralph W. 1998. ''Holbrookia propinqua''. Interpretive Atlas of Texas Lizards, No. 19. Southern Illinois University at Edwardsville, Edwardsville, Illinois. 1-14 pp.

Subspecies

There are three recognized

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 ...

of ''Holbrookia propinqua'': *northern keeled earless lizard, ''

Holbrookia propinqua propinqua ''Holbrookia'' is a genus of earless lizards, known commonly as the lesser earless lizards, in the family Phrynosomatidae. The genus contains six recognized species, which are found throughout the Southwestern and Central United States and nort ...

'' Baird & Girard, 1852 *southern keeled earless lizard, ''

Holbrookia propinqua piperata ''Holbrookia'' is a genus of earless lizards, known commonly as the lesser earless lizards, in the family Phrynosomatidae. The genus contains six recognized species, which are found throughout the Southwestern and Central United States and nort ...

'' H.M. Smith & Burger, 1950 *Stone's keeled earless lizard, ''

Holbrookia propinqua stonei ''Holbrookia'' is a genus of earless lizards, known commonly as the lesser earless lizards, in the family Phrynosomatidae. The genus contains six recognized species, which are found throughout the Southwestern and Central United States and nort ...

Harper Harper may refer to: Names * Harper (name), a surname and given name Places ;in Canada * Harper Islands, Nunavut *Harper, Prince Edward Island ;In the United States *Harper, former name of Costa Mesa, California in Orange County * Harper, Il ...

, 1932

References

* Holbrookia Reptiles of Mexico Reptiles of the United States Fauna of the Southwestern United States Fauna of the Rio Grande valleys Reptiles described in 1852 {{lizard-stub