The rock horned lizard (''Phrynosoma ditmarsi''), also known commonly as Ditmars' horned lizard and ''camaleón de roca'' in

Mexican Spanish Mexican Spanish ( es, español mexicano) is the variety of Dialect, dialects and Sociolect, sociolects of the Spanish language spoken in Mexican territory. Mexico has the largest number of Spanish speakers, with more than twice as many as in a ...

, is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

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 al ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Phrynosomatidae The Phrynosomatidae are a diverse family of lizards, sometimes classified as a subfamily (Phrynosomatinae), found from Panama to the extreme south of Canada. Many members of the group are adapted to life in hot, sandy deserts, although the spin ...

. The species is

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 els ...

to the Mexican state of

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...

, in northern

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 Guate ...

, south of the

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

border. Bearing the shortest horns of all the horned lizards, it lives in thorn-scrub and

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

Sinaloa Sinaloa (), officially the Estado Libre y Soberano de Sinaloa ( en, Free and Sovereign State of Sinaloa), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. It is divided into 18 municipalities and ...

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

s. The rock horned lizard was "lost" to science for about 65 years. It has a unique

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

preference and limited distribution. It also had a very imprecise

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

locality record which made it difficult to locate. An extraordinary effort by

Vincent Roth Vincent ( la, Vincentius) is a male given name derived from the Roman name Vincentius, which is derived from the Latin word (''to conquer''). People with the given name Artists * Vincent Apap (1909–2003), Maltese sculptor * Vincent van Gog ...

based on a cross-correlational analysis of gut contents from only three specimens led to its rediscovery.

Etymology

Its specific name, ''ditmarsi'', is in honor of Raymond Lee Ditmars, the first curator of reptiles of the

Bronx Zoo The Bronx Zoo (also historically the Bronx Zoological Park and the Bronx Zoological Gardens) is a zoo within Bronx Park in the Bronx, New York. It is one of the largest zoos in the United States by area and is the largest metropolitan zoo in ...

, and a pioneer in

herpetology Herpetology (from Greek ἑρπετόν ''herpetón'', meaning " reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and r ...

. (''Phrynosoma ditmarsi'', p. 73).

Habitat

The preferred natural

of ''P. ditmarsi'' is rocky areas in

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

and

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It ...

Description

The rock horned lizard has its occipital and temporal horns reduced to flaring expansions. It has a deep and narrow occipital notch and a high postorbital ridge. The

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

s of ''P. ditmarsi'' feature a large vertical expansion. It has a bare tympanum in the anterior neck fold posterior to a vertical row of four spines. It has a single row of lateral abdominal fringe scales, which are bluntly pyramidal.

Reproduction

''P. ditmarsi'' is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), a ...

. www.reptile-database.org.

References

External links